# 2000 Windstar AC pressure low



## Bigplanz (Apr 10, 2009)

Since it was 80 degrees here yesterday, I was reminded my wife's Windstar needs the AC fixed. Me, or somebody, is going get the AC working!

Here is a video. Compressor will come on if I jump the low pressure switch. It has a leak somewhere, I guess, but I will add some refrigerent to see if the AC briefly comes back to life.


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## papereater (Sep 16, 2016)

If you are sure there is a leak best approach would have been to apply vacuum to 29.9 mercury and watch guages. It they loose vac within 15 minutes then brush on soapy water at connections. Why bother to add refrigerant at this point. Let me know what happens.

Bewaare of a little known source of leaks- the black low pressure line. It could seep gas and diffficult to verify.


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## Bigplanz (Apr 10, 2009)

papereater said:


> If you are sure there is a leak best approach would have been to apply vacuum to 29.9 mercury and watch guages. It they loose vac within 15 minutes then brush on soapy water at connections. Why bother to add refrigerant at this point. Let me know what happens.
> 
> Bewaare of a little known source of leaks- the black low pressure line. It could seep gas and diffficult to verify.


I would pull a vacuum on it, if i had a vacuum pump.  Since it snowed yesterday, I hit "pause" on the AC troubleshooting.


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## papereater (Sep 16, 2016)

Understand, Bigplanz. Hey, got a compressor? You can buy a $10 vac venture at HF. That's what I use! No need for a $250 vac pump! 

Let me know how you progress as I have been around auto ac for a while......


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## Brainbucket (Mar 30, 2015)

2000 Windstar is an 18 year old vehicle. Check the Schrader valves for leaks. But 9 times outa 10 it's the evaporator. See if you can put the green die in it. You may watch the compressor turn green.:vs_cool:


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## Bigplanz (Apr 10, 2009)

papereater said:


> Understand, Bigplanz. Hey, got a compressor? You can buy a $10 vac venture at HF. That's what I use! No need for a $250 vac pump!
> 
> Let me know how you progress as I have been around auto ac for a while......


I thought about that venturi vac. My compressor is too small, though. 3 gallon pancake. Might get a vac pump from harbor freight with a 20% coupon. Should be about $80.


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## Brainbucket (Mar 30, 2015)

No sense in vacuuming the system until you find your leak. If you vac the system and then spray something on it to see if it leaking, you'll draw it into the system. Charge the system first then spray soapy water on the connections, compressor, condenser, lines, and shrader valves where you hook up to charge it. Looks like a tire valve. The only way to check the evaporator without removing it is to test it with a A/C leak detector. Fords are bad about leaky evaporators.:vs_cool:


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## Bigplanz (Apr 10, 2009)

Brainbucket said:


> No sense in vacuuming the system until you find your leak. If you vac the system and then spray something on it to see if it leaking, you'll draw it into the system. Charge the system first then spray soapy water on the connections, compressor, condenser, lines, and shrader valves where you hook up to charge it. Looks like a tire valve. The only way to check the evaporator without removing it is to test it with a A/C leak detector. Fords are bad about leaky evaporators.:vs_cool:


I am planning on doing just that. I am going to get a can of r-134a with dye in it, put it (and enough r-134a to get the system pressure up enough for the compressor to come on) and run the AC for enough time to distribute the dye. Then check with UV light and the funny amber glasses.

If the evaporator is leaking, yikes! whole dash has to come out! If it's a line or seal, eh, I think I can fix that. Compressor, eh, maybe? It's the wife's car so I consider it, um, a test platform! 

Still cold here, so this isn't pressing. Plenty of time to scour Amazon for what I need.

I read sniffers aren't very reliable for AC leaks. Opinions? I found them on amazon for about $30-$40.


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## Bigplanz (Apr 10, 2009)

It was sunny and 80 yesterday so I went to AZ and got a can of uv dye shots, a kit with the yellow glasses and a uv penlight and another 12 oz can of r-134a. Got sidetracked so I didn't get a chance to charge the system. Now it 55 and raining.

I assume only one shot of dye is needed, correct?


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## user_12345a (Nov 23, 2014)

If there's no gas in the system, don't add refrigerant and run it with air/moisture. 





papereater said:


> If you are sure there is a leak best approach would have been to apply vacuum to 29.9 mercury and watch guages. It they loose vac within 15 minutes then brush on soapy water at connections. Why bother to add refrigerant at this point. Let me know what happens.
> 
> Beware of a little known source of leaks- the black low pressure line. It could seep gas and diffficult to verify.


If automotive a/c system is anything like other refrigeration systems, the dumbest thing you can to do a system with a leak is pull a vacuum. Vacuums pull moisture in.

For non-automotive they usually do leak testing with nitrogen if there's no gas in the system.

If there is gas but it's low, could use a leak detector. or if it's flat, put a tracer gas plus nitrogen and use a leak detector.

The vacuum is only pulled to remove air/moisture from a leak free system before charging it up.


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## Bigplanz (Apr 10, 2009)

The results of today's testing! Opinions, please!


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## papereater (Sep 16, 2016)

Bigplanz said:


> The results of today's testing! Opinions, please!
> 
> https://youtu.be/u-rLsxqeA44


Big,

In my opinion, suspect a bad compressor if high side psi is way low. You didnt say if you indeed had any even slightly cool air ion the cab, but I assume you have absolutely no cool air. be happy if indeed it ends up being a bad comp and not a bad expansion valve, requiring yanking the dash. Just did such a job. Sheesh.


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## papereater (Sep 16, 2016)

user_12345a said:


> If there's no gas in the system, don't add refrigerant and run it with air/moisture.
> 
> 
> 
> ...


Fearmongering. Ive done the soap bubbles test many times and my ac's have not exploded/quit/siezed/rusted/fell off the car.

remember- it's SOAP. The water content on a few soap bubbles is so insignificant- they are mostly air. And the drier will absorb up to 10 mls of water. Also, youre vacuuming the system so the moisture will boil off and be expelled by the vac pump/venturi. 

Nitrogen? Yes, it is an "ideal" idea but it is so impractical to get a hold of some comprsessed N gas, which is under extreme psi. You need special fittings, etc. Not worth the hassle. 

And a vac is not used ONLY to pull a vac from a leak free system. It is also used to VERIFY there is no leak by watching the guages' needles over a few hours.

Dont be afraid, Bigplanz.


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## Bigplanz (Apr 10, 2009)

I ain't a skeert. 

The air coming out wasn't cold. The compressor was on, the pressure on both sides was the same. Ergo, compressor wasn't compressing. I will replace the compressor, condenser, drier and orifice tube. I will buy a vacuum pump, pull a vacuum, recharge and see if it works. I ain't skeert.

If it don't work, i try something else!

This will be on video.


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## user_12345a (Nov 23, 2014)

papereater said:


> Fearmongering. Ive done the soap bubbles test many times and my ac's have not exploded/quit/siezed/rusted/fell off the car.
> 
> remember- it's SOAP. The water content on a few soap bubbles is so insignificant- they are mostly air. And the drier will absorb up to 10 mls of water. Also, youre vacuuming the system so the moisture will boil off and be expelled by the vac pump/venturi.
> 
> ...


A vacuum is only 14.x psi below atmospheric so finding a leak with a vacuum in theory is less effective than with nitrogen where it can be like 150+ psig above atmospheric. In fairness, a micron guage would be way more accurate and pick up subtle changes that would never show on manifold gauges.

Yes, if there's a leak and a vacuum is pulled, air/moisture will be pulled in so it doesn't sound like an optimal tool to find leaks primarily.

I'm in no position to say that the practice is wrong, but it sounds like automotive work is held to a lower standard than ac or refrigeration. 

Refrigerant and parts seem to be sold to anyone in the us and the average diy'er won't charge by weight and probably doesn't know the theory.


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## polychrome (Oct 4, 2013)

papereater said:


> Fearmongering. Ive done the soap bubbles test many times and my ac's have not exploded/quit/siezed/rusted/fell off the car.
> 
> remember- it's SOAP. The water content on a few soap bubbles is so insignificant- they are mostly air. And the drier will absorb up to 10 mls of water. Also, youre vacuuming the system so the moisture will boil off and be expelled by the vac pump/venturi.
> 
> ...


Please don't try to pull a vacuum and find the leak using soapy water. That soapy water won't blow any bubbles when the system is in a vacuum.

Please don't try to use a venturi device to pull enough vacuum to do anything useful to a refrigeration system. 

You can find a leak by adding some dye, there are cans that include a few ounces of refrigerant and stop leak for around $8. The stop leak will only be effective for a shrunken o-ring, not an old condenser with pinholes. 

You can find even very small leaks with a Halogen leak detector. The cheapest are over $30 on Amazon, over 70 at harbor freight. 

If its been at zero or negative pressure, and if it was below the pressure cutoff on a warm day, it probably has been at negative pressure in very cold weather, you need to replace the filter dryer. The prices vary, but it would be difficult to find one for less than $12. The one in there will be saturated and then they can fail (when they can't remove all the water the screen that hold the desiccant in place can corrode) and release it. That could keep you busy cleaning out the expansion valve and flushing the rest the system.

You do need to use a vacuum pump to get rid of air and dry out the system. They run $100 at Harbor Freight now, but just over $50 on Amazon. The fill and vent method to purge trapped air has been unlawful for decades, not to mention expensive, and it was never as effective at removing air, it was all but useless for drying it out, and it's not much help finding leaks either. That said, some joint and o-ring leaks are pressure/vacuum sensitive and a vacuum test can fail to locate a pressure leak and a leak under vacuum be caused by o-rings that don't leak with positive pressure. Most (all) Schraeder valves will leak when you pull a vacuum, make sure any ports you have capped have good caps tightened down.

After you find and fix the leak, then its time to refill the system. If you can't find it, try patience. It can take a while for a slow leak to spit out enough dye to find it.

When you refill the system, don't use any of the crackpot junk that says its better than R134a. Yes, 134a is a blend only a bureaucrat could love, but tossing in a few percent propane (that's the secret ingredient, and the secret is its cheaper) doesn't really work, its an OK working fluid at 2x higher pressures than a 134a system uses, albeit flammable. Be sure to shake the can and turn it upside down and let it shoot it in as a liquid. If you let it boil in the can and go in as a gas the blend fractions itself in the can and you get the more volatile part until the halfway mark and you get lousy cooling. Try to run in as much of the charge weight as you can as liquid into the high pressure side with the car and A/C off, then wait a couple minutes before starting the car and running the A/C and finishing with more liquid (slowly) into the low pressure side. You won't be able to weigh the charge, but the label on the car will show a weight and you can figure it as so many full cans and then a fraction of a can. Try to get the fraction as close as you can manage. Look at the sweat/frost level, use a non contact thermometer to find the liquid level, shake it and guess, whatever works. You can practice on the cans you run in entirely.


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## user_12345a (Nov 23, 2014)

> When you refill the system, don't use any of the crackpot junk that says its better than R134a. Yes, 134a is a blend only a bureaucrat could love


134a is not a blend unlike most ozone friendly refrigerants like 407C and 410A. 

So should be able to take it from the can as a gas without any issues.


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## polychrome (Oct 4, 2013)

user_12345a said:


> 134a is not a blend unlike most ozone friendly refrigerants like 407C and 410A.
> 
> So should be able to take it from the can as a gas without any issues.


Yes, 134a is not an azeotropic blend, I'm not sure why I cross wired that thought. 

What I failed to say was that if it's lost the entire refrigerant charge it will have lost some compressor oil with it and it would be safer to use one of the automobile refills with a few oz of the correct oil for the system as the 1st can, hence the shaking and allowing time to let the oil in the 1st can move through the expansion valve. Its possible this will cause a problem with too much oil moving around, but its not likely and curable but the MTTF of an unlubricated compressor is roughly the time it takes to put all the tools away and get stuck in traffic.


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## Bigplanz (Apr 10, 2009)

It still showed about 20 psi on the system before i filled it. Before it started raining, i got my yellow glasses and UV lights and saw green dye on the underside of the compressor, a tiny amount on the hi and low fittings and little green flecks on the condenser. I will take some pictures.


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## polychrome (Oct 4, 2013)

Bigplanz said:


> It still showed about 20 psi on the system before i filled it. Before it started raining, i got my yellow glasses and UV lights and saw green dye on the underside of the compressor, a tiny amount on the hi and low fittings and little green flecks on the condenser. I will take some pictures.


I’m impressed you’re attempting to photograph the black light fluorescence. I’d have assumed that needs special filters. 

From the description I’d guess the fittings show dye from when the gauges are attached and removed.

The condenser isn’t certain, some bug splat and other debris fluoresces. If there’s also or exclusively fluorescence that’s not the exact same color as the dye, or if you don’t see anything on the fan blades and fairing, then it’s very unlikely to be leaking at all. If you had seen patches or spots rather than flecks, or there was dye on the fan or fairing, I’d suspect the condenser was losing refrigerant. 

Assuming the compressor isn’t just showing material that was ejected from the condenser and landed on it (the fan etc would also show it), then the questions are;
1) Are the line fittings leaking at the compressor? The car’s old enough for the o-rings to have failed. 
2) Is the leakage from the shaft? It’s possible that the shaft seals leak at zero pressure and it’s meaningless, but it could be a pressure leak.

The 20psi residual pressure you found is well below the vapor pressure of R134a refrigerant at any temperature most people think of their A/C. There may be a small residue of refrigerant dissolved in the compressor oil that’s a source for a dwindling leak. You may be measuring the vapor pressure of a minor constituent or contaminant - a tiny amount of solvent added to improve solubility of PAG oil to improve oil return, or an oil intended to swell o-rings in a leak-stop.

If the charge was lost at the compressor fitting or shaft definintely find out how to get the oil level in the compressor right. There’s always a way, even it it’s flush it out with compressed gas and add X ounces. As mentioned before, change the filter dryer.

If you don’t see anything elsewhere on the lines, and nothing where the condensation drips, then I’d replace the o-rings in the line set connections, and while it’s at zero pressure I’d change every other line set connection o-ring I could reach without taking the dashboard apart. Then I’d clean up the compressor, and every other connection and then add just enough gas to make it leak if it plans to, say 40psi. You can use R134a, Nitrogen, CO2, Argon, almost anything is fine that’s lawful to use as long as it’s dry and oxygen free and you remove all of it before you refill the system. I wouldn’t use propane though, whatever other considerations apply, the job is enough to to without smell of mercaptan.

If you don’t see any more leaking, then pull a vacuum and dry the system out. If it’s not leaking you may need to run the pump for an hour or 4 to dry it or trapped water and refrigerant dissolved in oil everywhere in the system will vaporize and look like a leak. If you can close it off and it’s still in a deep vacuum the next day, fill it , look for leaks, test it, and look for leaks one last time.


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## polychrome (Oct 4, 2013)

I just noticed you’ve been posting threads annually to chase down this same Windstar’s A/C leak on and off since 2016. I assume you started early because your wife isn’t happy “Windows Down”. (It’s always a lose-lose choice in the rain.)

Since it’s been out of commission for years, you’ll be wasting your time fixing it and a/c parts will quickly fail one after the other if you don’t change the filter dryer when you open it up.


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## Bigplanz (Apr 10, 2009)

polychrome said:


> I just noticed you’ve been posting threads annually to chase down this same Windstar’s A/C leak on and off since 2016. I assume you started early because your wife isn’t happy “Windows Down”. (It’s always a lose-lose choice in the rain.)
> 
> Since it’s been out of commission for years, you’ll be wasting your time fixing it and a/c parts will quickly fail one after the other if you don’t change the filter dryer when you open it up.


Yeah, her AC has been out at least a year. I convinced her that "windows down" would be ok for her. That line of reasoning isn't flying this time around. 

Last year I didn't have gauges, so I was not able to really test anything. Picked up some gauges last fall, and a can tap. Looks like I will getting a cheap vacuum pump soon!

I want to get this AC working. Compressor, at least to me, seems bad. Clutch turns, but the hi and low pressure doesn't change. Max AC, and the hi and low were 60 psi, with clutch engaged and the fans on. 

I will put a compressor, accumulator and an orifice tube in it, minimum. Not sure if I should change the condenser. Praying the evaporator is still good, as that requires removing the dash to get out.

I will shoot some pictures. I will hold the yellow glasses up to the camera on the phone, and shoot the pictures through that. It should work.

Close to 80 when I shot the videos, today it's snowing.


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## polychrome (Oct 4, 2013)

Bigplanz said:


> ...
> I will put a compressor, accumulator and an orifice tube in it, minimum. Not sure if I should change the condenser. Praying the evaporator is still good, as that requires removing the dash to get out.
> ...


An automobile A/C doesn't usually have a capillary tube, they have a thermal expansion valve, aka TXV. It has a sensing bulb on a fine tube that controls a valve at the evaporator inlet to hold the return line temperature above the point where it might return liquid to the compresor. A TXV is less susceptible to clogging than a capillary, and opens wider to feed refrigerant faster when you turn the A/C on. You shouldn't need to replace the TXV.

... and now the bad news, if you've had a compressor failure you have to figure out if it's pumped metal shavings and powdered metal around. If it has you'll need to flush the system. Every fitting you take apart will be oily. Touch the end of the tube to clean white paper toweling. If the oil residue is only yellowish, you're OK, if you see grey, or metal particles, you have to flush. If its been empty for too long to drool oil use a q-tip to swab the inside of the tubing and look at that.

You flush in segments. Typically compressor through condenser to receiver fitting is one segment, receiver to TXV is another, and evaporator to compressor. If you can't get to the TXV to separate it there, then you can't. If this Windstar has both front and rear A/C evaporators find a way to flush them separately.

You can use use one or more clever can kits with solvent that's sold at the stores to flush it. Just blowing compressed air won't get the metal particles out, there's oil in there holding them to the tube walls, and you're likely to blow in water with a little bit of rust from your compressor. They don't use ideal solvents so after reassembly you may have to pull a vacuum for hours to evaporate the last of it out. Methods using better solvents require tools that aren't worth investing in to repair 1 car.

FWIW, bypassing a low pressure switch is usually a bad idea and can cause compressor failure. (for a home A/C it *will* cause failure within a few minutes) The inner parts are cooled by refrigerant and lubricated by oil that circulates with the refrigerant. When the refrigerant is missing, the oil often is too. I think your WindStar's compressor died 2 years ago, so it didn't matter one way or the other, but it's not a good way to troubleshoot.


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## Bigplanz (Apr 10, 2009)

polychrome said:


> An automobile A/C doesn't usually have a capillary tube, they have a thermal expansion valve, aka TXV. It has a sensing bulb on a fine tube that controls a valve at the evaporator inlet to hold the return line temperature above the point where it might return liquid to the compresor. A TXV is less susceptible to clogging than a capillary, and opens wider to feed refrigerant faster when you turn the A/C on. You shouldn't need to replace the TXV.
> 
> ... and now the bad news, if you've had a compressor failure you have to figure out if it's pumped metal shavings and powdered metal around. If it has you'll need to flush the system. Every fitting you take apart will be oily. Touch the end of the tube to clean white paper toweling. If the oil residue is only yellowish, you're OK, if you see grey, or metal particles, you have to flush. If its been empty for too long to drool oil use a q-tip to swab the inside of the tubing and look at that.
> 
> ...


I by-passed the switch only long enough to see if the compressor came on. It did, and I shut it off.

This particular mini-van has an orifice tube. The model that has the rear AC option also has an expansion valve, but that doesn't apply in my case. To my knowledge, it appears the compressor seal failed, allowing the refrigerant to escape. The clutch still works, doesn't bind or rattle. This makes me think the compressor didn't grenade on me and send metal shavings through the whole system. I guess I'll find out when I take it apart. 

This is going to take awhile, though. Got to wait until next Friday to even think about buying parts. Plus, well, it is still cold here and the AC isn't critical right now. I will post more when I do the install. Probably a separate thread.


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## Brainbucket (Mar 30, 2015)

Compressor and drier. If you can remove the orifice tube, just blow it off. If it is in the liquid line, change the line. Vacuum then charge it with the correct amount of Freon. Get a new compressor, not a remanufactured one as they have a higher rate of frailer. I always dump the oil out of the new compressor. Never had one fail because of that. The system has enough in it and you can't get all the oil out of the compressor. If too much oil is in the system, it won't cool very well. Also change the shrader valves where you hookup to the system. Been doing A/C for 40 years.:vs_cool:


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## Bigplanz (Apr 10, 2009)

Brainbucket said:


> Compressor and drier. If you can remove the orifice tube, just blow it off. If it is in the liquid line, change the line. Vacuum then charge it with the correct amount of Freon. Get a new compressor, not a remanufactured one as they have a higher rate of frailer. I always dump the oil out of the new compressor. Never had one fail because of that. The system has enough in it and you can't get all the oil out of the compressor. If too much oil is in the system, it won't cool very well. Also change the shrader valves where you hookup to the system. Been doing A/C for 40 years.:vs_cool:


I appreciate your (and everyone's) help and advice. Lots of videos on Youtube in re: AC work. I try to find the ones from actual techs and people who work in or own their own shops. "FordTechMakuloco" is a good one, with lots of detailed videos on AC work on Fords.

Mostly, the tech advice is pretty much what BB is saying. Equal pressure on both sides with a running compressor means bad compressor. Replace it, the accumulator and orifice tube. At a minimum, the compressor and accumulator. Pull a vacuum, and if no leaks recharge. Replacing shrader valves is also advisable since they are cheap and easy to replace on an empty system.

In re: oil, they measure what was in the system, then replace that. Haynes says make sure at least 4 oz of oil is in the new compressor. Also says drill a hole in the bottom of the old accumulator, drain the oil and add the same amount in the new one.

I looked over the system again with the UV light last night. Lots of what look like splashes from where the dye spewed out on the firewall, body panels, etc. Wish I had thought to wrap a shop rag around the dye can when I put it in.

Only real pronounced evidence of dye other than splashes was on the shrader valves (both of them, so I suppose the hi side is leaking) and on the underside of the compressor.

Next Friday I get paid, so I will order something from Rockauto. Thinking about kitting this kit for $150. Anybody know anything about this company? Compressor has a 2 year warranty.

Looks like Derby week will be busy! I will probably be doing this job on Derby Day while everybody else is at the track. 

Thanks again, for everyone who has posted!

https://www.rockauto.com/en/moreinfo.php?pk=5242821&cc=1362844&jsn=704


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## papereater (Sep 16, 2016)

Bigplanz said:


> Next Friday I get paid, so I will order something from Rockauto. Thinking about kitting this kit for $150. Anybody know anything about this company?
> 
> https://www.rockauto.com/en/moreinfo.php?pk=5242821&cc=1362844&jsn=704


I trust you got paid Friday, Planz. Yes, I do know something about Rock Auto. Use them all the time. For years. Some stuff is not 1st class. One rack/pinion set I bought for my Pontiac started a slow ooze/leak within 2-3 years (only say, 14,000 miles). Still have it. But overall, no problems. But you can buy Reman'd ac comps anywhere. I have had good luck with all I have bought for my cars. A 2 yr warranty is good. Usually you get 1 yr.


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## Bigplanz (Apr 10, 2009)

I popped open the grill Saturday to get a better look at the condenser. I checked it with the UV light and didn't see any dye. I ordered one of those sniffers to poke around down there and in the vents to check the evaporator.

Getting the condenser out is somewhat challenging, but not too bad. I will leave it alone if the sniffer doesn't go crazy. Same with the evaporator. Evaporator removal doesn't require removal of the entire dash, thankfully, but if it ain't broke don't fix it. Hopefully, I can get this AC going with just a compressor, new o-rings, schrader valves, accumulator and orifice tube.

This should be fun!

Video of me poking around under the hood.

(I cleaned the throttle body and replaced the PVC valve while I was under the hood. Throttle body was pretty dirty!)


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## papereater (Sep 16, 2016)

Right, Planz- it IS a lot of fun. AC is so cool. Let us know what happens.


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## Bigplanz (Apr 10, 2009)

Oops! I was mistaken, this mini-van is an LX model and does have rear A/C. I guess that means pressurizing the system, putting it on jack stands, and crawling underneath and using the sniffer on the lines running back to the rear evaporator. Who knows what I'll find? Experience is the best teacher, and all that.


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## polychrome (Oct 4, 2013)

RE: Only the compressor seals failed ... its not rare, but IIRC seals are often a secondary failure i.e. the seals fail when the bearings fail, and the bearings fail when there's no lubrication or its full of powdered metal that used to be the piston. It looks like a DENSO 4718127 is around $125 from competitive sources.

When swapping out the compressor, when you remove the lines, look into the old unit's ports. If you see anything black, don't connect the new one without flushing, and if its rubber, find the dead hose.

Not sure what the procedure is to remove the condenser on a Windstar. On the similar 2000 Caravan you remove the upper radiator cross panel and the front bumper cover / grille to get to it.

RE: Brainbucket & dumping the oil from a new compressor... Yes, you should dump some if you didn't have to flush the system, how much to dump depends on what you find in the old compressor. You don't dump it all, and if you flushed the system you don't dump any of it. 

Use this tech tip from Denso as a reference. http://www.denso-am.com/products/au...-compressors/practical-tip-on-compressor-oil/


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## papereater (Sep 16, 2016)

Bigplanz said:


> Oops! I was mistaken, this mini-van is an LX model and does have rear A/C. I guess that means pressurizing the system, putting it on jack stands, and crawling underneath and using the sniffer on the lines running back to the rear evaporator..


Or you can just pressurize (with what? R134a? Nitrogen? If so, how?) and watch the gauges for movement for 1 hour. Unless you enjoy crawling under the van..........


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## polychrome (Oct 4, 2013)

papereater said:


> Or you can just pressurize (with what? R134a? Nitrogen? If so, how?) and watch the gauges for movement for 1 hour. Unless you enjoy crawling under the van..........


RE: Pressurize with what? You can pressurize with your favorite dry inert gas, including the ones you mentioned, as long as it works with whatever method you've chosen to locate the leak. 

RE: just watch the gauges... <radio announcer voice> "...when we last heard from our hero..." he had put in some UV leak detection dye and had a UV flashlight and yellow glasses. So the most expedient next step would be to look to see it the dye had leaked from the lines underneath the body that connect a second evaporator in the rear.

Watching the gauge set for movement doesn't work all that well for slow leaks and never shows where the leak is anyway. Working outdoors, particularly at this time of year, the rapidly changing outdoor temperature changes the pressure of any gas you put in the system. It can mask a real leak when the temperature is rising or send you on a snipe hunt for a non-existent leak when its falling. Repairing a leaking A/C indoors where the temperature is stable risks being asphyxiated by leaking refrigerant.


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## papereater (Sep 16, 2016)

user_12345a said:


> Refrigerant and parts seem to be sold to anyone in the us and the average diy'er won't charge by weight and probably doesn't know the theory.


The average DIY'r does not do auto ac. The average DIY'r does not know how to do a complete auto ac teardown, and rebuild, with acceptable results. 

I agree- the average DIY'r knows just enough to attempt to fix ac by simply adding/pumping in more refrigerant, even with the risk of personal injury.


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## papereater (Sep 16, 2016)

Oh- also, beware of rampant, even contagious fearmongering. For the record, and for anyone interested (as many wont even care) checking for a leak with gauges is a well recognized method. Also, regarding "slow" leaks, some slow leaks are actually almost impossible to detect, even with expensive "sniffers". Man's technology has its limits.

One leak I detected was so slow, losing a can's worth of gas in 2-3 months- was finally detected only by my own nose, using ES-12, laced with a strong pine scent. I doubt many ac people ever heard of this method. I am volunteering it, maybe you may try it some day after you have spent much $$$ and time chasing the most elusive leaks with the more expensive gadgets. 

And I still stand by the method of vacuuming down with a venturi AND a compressor- not a cheap method by any means- just practical IF you already have a compressor. A vac of 29.9" Hg is the same vac whether taken by a venture of anything else. 

Again, let's stop scaring Bigplanz.


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## Bigplanz (Apr 10, 2009)

papereater said:


> The average DIY'r does not do auto ac. The average DIY'r does not know how to do a complete auto ac teardown, and rebuild, with acceptable results.
> 
> I agree- the average DIY'r knows just enough to attempt to fix ac by simply adding/pumping in more refrigerant, even with the risk of personal injury.


Well, this will be the first time I have ever attempted this level of A/C work. I have researched the matter pretty well the last few weeks, so, well, who knows? Maybe I will succeed, maybe not. I will report back.

In re: the rear evaporator, and getting under the van, well, yeah, I dye tested it, so if there is a leak back there, it should show up. I didn't turn the rear A/C on, though, so maybe not. I will drive the van up on ramps when it is sunny and nice Saturday for a look-see. Probably do some other things under there too, like check out the belt tensioner location. Can't get to it from above! At least not easily. Nice design!

I got a cheap sniffer from Amazon this week, so I will pop another can of R-134a in the system, get the pressure up to at least 50 psi, get the compressor to turn on, make sure the rear A/C is on this time, and maybe even add the last little bit of UV dye I have left. Then, after it runs for a while, I will get under there with the glasses, the UV light, the sniffer and go hunting snipe.

Been reading up on all sorts of A/C related topics. According to Section 609 of the EPA rules on Mobile A/C systems, it is illegal for a person receiving "compensation" to vent refrigerent. Since I am not receiving said compensation, I am ok. Of course, the whole matter is moot, as the pressure leaks down so fast the system is pretty much empty even a week after I charge it up to test.

If, however, I was going to do something to my Navigator (with a working A/C system) I would take it to a shop to have the system evacuated. An old beater Windstar with an A/C that hasn't worked in at least 2 years? No.

Reading up on something doesn't make me, or anyone, an expert or qualified to work on something for pay, for someone else, but I am ok with working on my van, in front of my house, and taking my chances on whether I succeed. Cost me a couple of hundred bucks, but, you know, it's my money, my time, my trouble. It is me crawling around under there with the funny glasses. I can deal with it if it doesn't work.

Here is a really interesting link on EPA test material for 609 certification, if you want to get in the weeds on this topic.

https://www.epatest.com/609/manual/manual.jsp#_Toc460943779


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## Bigplanz (Apr 10, 2009)

papereater said:


> Again, let's stop scaring Bigplanz.


I am a pretty confident guy. I have always thought, "If you think you can do it, or if you think you can't do it, you're probably right."

If doesn't work, hey, so what? At least I didn't blow $200 or $300 at the track watching the Derby. 

Oh yeah! I forgot to add.... I found a used 2000 Windstar 3 volume shop service manual for $25 on ebay! Ordered it today.


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## papereater (Sep 16, 2016)

Right, Planz. No need to get too academic about common sense stuff. And usually, as you know, you will save many $$ in the process with minimal risk. We are here to offer useful/practical help to fellow members.


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## Bigplanz (Apr 10, 2009)

papereater said:


> We are here to offer useful/practical help to fellow members.


And I appreciate that very much! Thanks to all of you who take the time to post.


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## Bigplanz (Apr 10, 2009)

Orifice tube location? Factory service manual, which I got yesterday, says one thing, those guys on the internet say another. Anybody know for sure?


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## Brainbucket (Mar 30, 2015)

The orifice tube is generally on the liquid line connection at the evaporator, the small line. If not, trace the liquid line back till you see a connection and pull apart to see the orifice tube. By the way, your tube is red. There are different colors, white, blue, black, red, and so on. And sometimes they are a pain to remove. Just be patient. the rear unit has an expansion valve. To check the evaporator with a sniffer, charge system, let it set overnight and put the sniffer in the drain tube and then turn fan on low. If there is a leak, the sniffer will go off. Make sure that just moving air doesn't set it off.:vs_cool:


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## user_12345a (Nov 23, 2014)

papereater said:


> Right, Planz. No need to get too academic about common sense stuff. And usually, as you know, you will save many $$ in the process with minimal risk. We are here to offer useful/practical help to fellow members.


When a sealed system is put under a vacuum to see if there's a leak, air which has moisture can leak in.

Further, with a vacuum the difference is only 14.7 psi so unless the op has a expensive micron gauge which picks up very subtle pressure changes, it's not a good way to find a leak. perhaps it works, it's not a best practice by any stretch.

Better to pump it up with nitrogen to a much higher pressure difference between atmosphere or use another method like a leak detector.

Or if there's refrigerant in there use a leak detector.

This is common sense and not "academic".

With refrigerant in there, would need to have a expensive recovery machine to do this work legally.

Probably best to get this professionally fixed.


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## Bigplanz (Apr 10, 2009)

Since the system pressure is near zero, there isn't any refrigerent to evacuate. Pulling a vacuum isn't too effective finding a small leak, but it will confirm a big one. Need a vacuum pump anyway to remove moisture prior to a recharge.

The Windstar is not a daily driver. My wife has health issues that make it hard for her to drive long distances. Back and forth to the store is about it. I think she put 1000 miles on it in the last year. Taking it to a shop would cost as much as the thing is worth. I will give it a shot


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## Bigplanz (Apr 10, 2009)

Today I did more testing and am confused. First, I added more refrigerant to get the compressor to come on. I got weird readings. It ran for 40 minutes, an the compressor was on the whole time. It never cycled. Reading settled at 55psi low side, 115psi hi side.

I used forscan to review AC PIDs. Attached is a screen shot. Basically, even though I turned on the AC, forscan says no request for AC occured.

Any ideas on what this might mean?


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## Bigplanz (Apr 10, 2009)

A video I shot about 7 pm. Compressor is cycling but the high side is elow 100 psi. Air though the vents is not remotely cold.


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## polychrome (Oct 4, 2013)

Bigplanz said:


> A video I shot about 7 pm. Compressor is cycling but the high side is elow 100 psi. Air though the vents is not remotely cold.
> 
> https://youtu.be/Q9zQkz6LI-k


Depending on the outdoor temperature those could be a set of "normal" system pressures for an R134a system, or it could be a significantly undercharged R134a system. 

From your description of the vent temperature I'd go with undercharged. I don't have a manual for a Windstar. For the entirely too similar 2000 Grand Caravan here's normal operation with both front and rear A/C blowers running at a full speed and the temperature sliders all the way to the cool end and with all the doors & windows wide open;

AMBIENT 70°F 80°F 90°F 100°F 110°F
CENTER OUTLET 34-46°F	37-49°F 39-50°F 43-52°F	45-65°F
DISCHARGE PSI
AFTER DRIER 50-250	220-330 290-380 300-430	330-496
SUCTION PSi 15-30 17-32 20-35	25-39 30-50

The temperature and pressure ranges are because dehumidifying, in a/c lingo latent heat, can be as many BTU as the duct temperature change which they call sensible heat. Expect the low numbers for dry air and the high ones for high humidity. Don't mix & match, a low suction pressure and a high discharge pressure means a blocked system possibly just the expansion valve, while a high suction pressure with low discharge pressure could mean mean the compressor is done for, but note that these are AFTER the filter drier so although it isn't all that common they can become blocked.

If the High side port is before the filter drier on the Windstar it shouldn't make a significant difference to these pressure readings as long as it isn't clogged up.

The Caravan like other systems with an expansion valve is charged most accurately by setting the subcooling in the liquid line. For this you want maximum refrigerant flow, if necessary use the heat controls to make the passenger cabin just plain hot. This mothod requires a thermocouple or a fairly good non-contact thermometer, but its simple to do. If you use a non-contact thermometer spray a little paint on a paper towel and wipe it on the high pressure tubing so it doesn't try to read a bare metal temperature, it wouldn't be correct. The correct temperature depends on the pressure. On your gauge set the high pressure reading has an R134a scale showing the boiling point for R134a at the current pressure. You want the actual temperature of the liquid line to be 25 degrees F lower, but the world won't end if its anywhere between 20 and 30 degrees. Less than 20 degrees of sub cooling implies you're undercharged, more than 30 implies you're overcharged. 

IIRC you have a rear A/C and that implies you should have an expansion valve for each evaporator rather than an orifice tube at each, but it doesn't matter. You can charge by setting the subcooling for either type of system, and 25F is a safe value for most any system.

You do have to wait a while for the effect of each refrigerant addition to stabilize.

If you have expansion valves you can't charge by the suction line temperature. The expansion valves keep the superheat almost constant until you have like 3x too much refrigerant in there.


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## polychrome (Oct 4, 2013)

I should have mentioned, the 1st set of readings 55 low side 105 high side don't make much sense given the second set of readings It could have been nothing more than the system bleeding its way back to equal pressures.

I should also have been a little noisier about not adding refrigerant and running it for a longtime to diagnose it without vacuuming out air and moisture.

The comment about running the fan and sniffing the drain tube... yes sniff the drain tube. shouldn't usually need the fan, but why not. You can also sniff the heater duct for your feet. If you change the controls to heat and feet and give it 1/2 second of fan if you have a leaky evaporator it will set the detector off. You can do likewise for the rear unit.


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## Bigplanz (Apr 10, 2009)

The Windstar has an orifice tube for the main AC and an expansion valve for the auxiliary AC. I am sure the system is severely undercharged, since I have only put one 12 oz can in, plus may 1/4 of another can. A full charge is 56 oz.

A little spendy, at $8 a 12 oz can, to fully charge up a leaky system, though. I will add the second can, though, and maybe a third, to check it out. I will try and see if the system starts to cool the car just to see if it is functional at some level. I want to diagnose this thing, rather than just throw parts at it.

There is no rush. Weather is still mild, and the car only gets maybe 100 miles a month on it.

The factory shop manual (3 volumes) I bought is pretty exhaustive about, well, everything. Great info source, and for $35 a bargain.


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## polychrome (Oct 4, 2013)

Along with the 56 oz of R134a it wants to have 11 oz of PAG 46 oil, or at least he Four Seasons Capacity guide thinks that's so. 

With the system so undercharged whatever oil is left in it will accumulate in the condenser and evaporator rather than return to the compressor. With the system almost certainly very short of oil because it left with the R134a, you're operating the compressor essentially without oil. Even if the compressor does have a shaft leak you won't be able to fix, $30 of R134 and oil will keepo it from shredding the pistons and save you a comparable cost for A/C flush solvent and save you the time and effort required to flush it. 

Since you seem to be cost conscious, and I really don't think you'll enjoy flushing the A/C ... on Amazon you can find 12 12oz. cans of R134a for around $60 or $5/can. The best 12oz single can price is at Walmart $6.15/can for 2 day delivery, and the best pick up today price is $8 at Autozone, or O'Reilly. If you don't mind buying 35.3oz at a time Pep boys sell that for $19.90 which would be similar to buying 3 12oz cans at 6.62 each. I buy 30lb cylinders which is only less expensive if you use it all.


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## polychrome (Oct 4, 2013)

I'm sorry to add yet another thing to consider to your leak detection puzzle but there's a chance it could save you some money. The link at the end is to a Four Seasons tech note about compressor shaft seals. The point they're making is that the shaft seal is lubed by oil and a small amount of oil will always migrate past the shaft seal carrying small amount of dye with it. The included tech note suggests doing specific things during a compressor change to make sure the seal is properly lubed that I don't recall ever doing for that reason. The point of passing the information along is to suggest that if the shaft seal is still the only leak you can locate it may be due to a lack of oil. I couldn't say that adding oil will seal it, but if adding oil does seal it up don't second guess it. I won't seal up if its worn out from friction or the added radial movement from a failed bearing.


http://www.4s.com/media/4914243/-AB339-Shaft-Seal-Lubrication.pdf


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