# The miracle of the heater core



## Bigplanz (Apr 10, 2009)

Now it leaks, now it doesn't.

Way back in March, my 2000 Navigator developed a fog on the inner windshield. This was not moisture, and took a good bit of rubbing to get off. Since warm weather was around the corner, I clamped off the heater hose and set the matter aside. 

Well, now it's cold again. I took off the clamp, drove around to replicate the issue so I could show it to a mechanic, and.... no more fog. System works perfectly. Plenty of heat, zero fog. Now, I know leaks don't repair themselves, so I expect it to return. Or, perhaps it's a miracle!

Nah.

Here is a video from March, the next one is a video I shot yesterday whe I took the clamp off the hose. Thoughts, opinions and suggestions requested!


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## Bigplanz (Apr 10, 2009)

Here is the video I shot yesterday.


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## Nealtw (Jun 22, 2017)

You are not alone, here is a google search.
https://www.google.ca/search?source...j33i22i29i30k1j33i21k1j33i160k1.0.Eaj1NHhGxME


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## de-nagorg (Feb 23, 2014)

Replace the heater core.

They develop a hairline crack in the solder that holds the tubes to the body of the thing.

In warmer temps (fall) the crack is sealed by expansion, in colder temps(winter, spring), the crack opens up due to contraction.

Could re-solder, but it still needs removed to repair, and new ones at auto-zone are not very expensive.

I remember telling you this before, but ?

I have done this several times over the decades that I have been driving.

Getting the core out and back is the hard part, just replace it and be done.

ED


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> Replace the heater core.
> 
> They develop a hairline crack in the solder that holds the tubes to the body of the thing.
> 
> ...


I recall you telling me this! To remove, or access the heater core costs a bundle. 1 grand, I am told. I left it as is since the spring for this very reason. Since it turned cold, I was ready to take it in for repair. Yet, it works perfectly now. Color me confused.


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## diymaster (Jun 24, 2016)

https://shop.advanceautoparts.com/p...-QHbpjUIw632wb3pEfxoCuvsQAvD_BwE&gclsrc=aw.ds


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## chandler48 (Jun 5, 2017)

Just be glad it isn't in a Ram 3500. Everything from the base of the windshield to thr front of the sat comes out. Dashboard, gearshift, everything. Easy grand.


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## Bigplanz (Apr 10, 2009)

diymaster said:


> https://shop.advanceautoparts.com/p...-QHbpjUIw632wb3pEfxoCuvsQAvD_BwE&gclsrc=aw.ds


I have never had any luck with stop leak. In fact, i don't have a leak. Not a drop on the ground. Not a drop anywhere. Fog on the windsheild last spring but have driven it around for two days with no problems. This is all very confusing.


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## cee3peeoh (Sep 12, 2017)

de-nagorg said:


> Getting the core out and back is the hard part...




Aye! That me bucko is the miracle!


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## de-nagorg (Feb 23, 2014)

Bigplanz said:


> I recall you telling me this! To remove, or access the heater core costs a bundle. 1 grand, I am told. I left it as is since the spring for this very reason. Since it turned cold, I was ready to take it in for repair. Yet, it works perfectly now. Color me confused.


The phenomena is simple physics.

Metal ( as well as everything else) expands and contracts in different temps.

When cold the metal shrinks just enough to open the crack enough for coolant to escape and blow all over the inside of the windshield.

Look up how to change a heater core on thr net, or get a paper manual for the Navigator.

I personally would do it myself if it were mine, but as I said " I have experience".

If I were not thousands of miles away I would help, but you know the drill, it would cost big $$ to travel to your home.

The best I can do is encourage you, I have seen you tackle more difficult things and succeed, so I know that you can do it yourself, for the cost of a new core and a couple of band-aids.


ED


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## cee3peeoh (Sep 12, 2017)

Maybe a 2000 F150 is the same?


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## Bigplanz (Apr 10, 2009)

Thanks for everyone's help and advice. This is very mysterious. The cooling system, of course, is pressurized. It heats up, pressurizes and the water pump circulates the coolant through the engine, the heater core and the radiator. The pressure is 15 psi, nominal. If there is a hole in a pressurized system it WILL leak. Every single time it is pressurized.

Tiny little holes, maybe not so much, but it will be evident there is a problem. If it's the radiator, there is coolant on the ground, or wisps of steam from a weepy hose connection, etc. The engine temp will rise, slowly perhaps, but it will rise.

If there is a heater core leak, no matter how small, there will be film on the windshield and perhaps wetness in the passenger side floorboard and an anti-freeze smell. This is fully what I expected when I took the clamp off the heater hose so coolant could flow again through the heater core. This is not, however, what has occurred. The system now has worked normally for three days. Why? I have no idea. I am simply going to continue to monitor it and enjoy the heat while it lasts. 

I did research the replacement procedure last spring. Whole dash has to come out, many items disconnected, steering wheel dropped, etc. Then, of course it all has to be put back together. I hope my luck holds out, as this procedure is way above my skill set.

Here's a video from this morning, taken when I got to work (6 mile drive).


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## bfletcher7 (Jan 16, 2016)

This is a moot point if you don't have tools and don't typically do some of your auto repairs but several years ago I was in a similar position; I had never pulled a dash but tackled brakes, bearings, ball joints, fuel pumps, water pumps, A/C compressors, etc. The more I looked at the quote for hiring a shop do it the more I reviewed the steps outlined in the service manual. After a few days I made the decision I was going to do it myself. In my case, on a Taurus, it really was not a _hard_ job. Yes, it was time-consuming and involved multiple steps but it went smoothly, except for removing the clamps and hoses at the firewall--that was the most difficult and time-consuming single step for me. I ended up replacing two heater cores on that car before the trans went out at 230k miles, lol.


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## Brainbucket (Mar 30, 2015)

Heater cores leak when they are corroded or a seam splits. When it stops, it's because of stuff in the cooling system plugging it up. It's gonna leak again. Just change it. The instrument panel has to come out before you can remove the A/C heater box. And yes the A/C has to be recovered.:vs_cool:


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## bfletcher7 (Jan 16, 2016)

Brainbucket said:


> And yes the A/C has to be recovered.


My bad... on my sedan I didn't need to dig into the evap housing.


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## Bigplanz (Apr 10, 2009)

Yeah, I read up on it. AC has to be recovered, coolant drained, dash off, steering wheel dropped, just to get to the core. .

All told, this is 7 or 8 hours shop labor, plus parts, plus materials, etc. Recommendation I read somewhere was replace the AC evaporator too, since you are already in there. $1200, conservative estimate. Probably more, actually.

Of course it will start leaking again. I expect it too. It's not leaking now though, so it will probably start leaking again in January when it is zero out. Since I don't have $1200+ spare cash laying around, I will just leave it alone. When it starts leaking again I guess I will be driving the wife's Windstar for a while. 

Thanks for the help and advice!


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## de-nagorg (Feb 23, 2014)

bfletcher7 said:


> My bad... on my sedan I didn't need to dig into the evap housing.


 Me neither, and I have changed at least a dozen over the last 5 decades, Maybe specifically to the Navigator.


ED


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## chandler48 (Jun 5, 2017)

I KNEW what I was up against, and just routed the heater hoses back to themselves and did without heat one winter. That'll prompt you to save up for the inevitable.


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## ChuckF. (Aug 25, 2013)

If you are really desperate for heat, you can get 12V heaters for the interior. Yes they use a lot of juice, 10-15A depending on the model.


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## cee3peeoh (Sep 12, 2017)

Before spending thousands, spend $6.














> PRODUCT DETAILS
> Part No.PLT11
> Warranty Details (30 DAY REPLACEMENT IF DEFECTIVE)
> 
> ...



I have used this many many time to seal a radiator leak. I like it a lot.


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## de-nagorg (Feb 23, 2014)

And I have changed several customers radiators after they used those Commercial "STOP LEAK" remedies.

It totally plugged 3/4 of the cooling passages in the radiators, causing OVERHEATING.

So if you use it go light on the stuff.


ED


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