# The curious case of the foggy windshield



## Bigplanz (Apr 10, 2009)

2000 Lincoln Navigator with the EATC temperature control system.

Things are foggy in my car. Outside morning temp, upper 30’s. Get in every morning, turn on the defroster, still foggy. Turn on the AC, foggy. Turn temp up or down, still foggy.

Run fan high, foggy, run fan low, foggy. 

All the temp controls work. I can hear the vents moving around when I change settings. Warm air comes out with temp turned up, cold air comes out when temp is turned down.

Not sure what to make of it. 

No film on the windshield. Leaky heater core was what I first thought. No oily film, no sweet smell, floor carpet bone dry. 

Very odd indeed. The coolant temp is normal. T-stat opens at 195, then stabilizes at 186 or so. Below is a short video. All suggestions on how to address this are appreciated, as it is rather hazardous to drive in a dense fog bank.


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## ddawg16 (Aug 15, 2011)

When is the last time you gave the inside a good clean?

The plastics in your cab outgas over time. This puts a thin film on the windshield...under normal conditions, it's not obvious. 

Use a good glass cleaner and give it a good cleaning.


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## MTN REMODEL LLC (Sep 11, 2010)

I'm not sure you verified that the vents for the windshield are operating correctly.

Could you have any sealing leaks (moon roof/luggage racks) introducing excess moisture at night.


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## de-nagorg (Feb 23, 2014)

I have seen that symptom occasionally.

The heater core develops a minute crack in one of the solder joints for the hose connectors.

It only leaks a tiny bit of coolant that fogs everything up, then as it heats up it self seals, and the leak stops.

Very hard to tell, because there is not enough moisture to cause all the tattles of coolant.



Or you have a stray cat peeing in the air intake, and that is where your moisture is coming from.


ED


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## clarenceboddick (Nov 30, 2016)

It's either the heater core or the AC evaporator leaking. You can easily bypass the heater core to test by rerouting the hoses to it.


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## Bob Sanders (Nov 10, 2013)

Is the back window fogging up too? If not then it's probably a coolant leak.

Normally the AC runs when you have it in defrost, even in high heat (it dehumidifies the air) so you should verify that, but I'm guessing a coolant leak. Coolant leaks usually leave a slight film on the window though. Clean the window and run it for a few days and check for a slight film on the window.


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## Bigplanz (Apr 10, 2009)

There is no moon roof or other opening on the roof. The rear window was fogged up too, this am. 

I went to autozone, got some glass cleaner, some rainx antifog and some heavy duty paper towels and cleaned the windshield.

I am leaning toward the minute coolant leak theory, mostly because I can't think of a more plausible explanation. I checked the coolant tank and it looks low to me, even though the SUV is showing normal coolant temps. NEVER above a max of 199.7 and that is very briefly (seconds) until the t-stat opens. Then it's in the mid 180's regardless of in town, interstate driving, whatever.

It is something I need to resolve. It is hazardous.

Oh, at lunch when I went to autozone it was upper 30's, bright sun. No fog developed even though I drove it around for about 40 minutes through city traffic. If it were a leak, I would think it would fog right up again. Once I parked, I cleaned the windshield and there was dirt/grime on the paper towel.


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## de-nagorg (Feb 23, 2014)

That dirt / grime is evidence of either a leak in the heater core, or a smoker occupying the passenger compartment.

Both leave a film on the inside of a windshield.

As one other suggested bypass the heater core temporarily and see if the fog goes away.

Of course wait until the weather gets a bit warmer, as this is your driver, and you don't want to go to work in an icebox.

ED


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## JIMMIEM (Nov 17, 2016)

Is there a cabin filter that you can check? The owner's manual for my car indicates that a foggy windshield may be due to a clogged/dirty cabin filter.


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## ukrkoz (Dec 31, 2010)

I REALLY hate to say this, nothing being implied... But what I KNOW is that hangover breath will cause fogged glass. Drinking yesterday and byproducts of alcohol break down in the body in breath WILL cause fogging glass. 
Just an observation. I worked at D&A rehab and they used this to check who was drinking yesterday during morning rounds... Ever since I quit, I never have fogging windows too, only normal perspiration effects am after gym.


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## ukrkoz (Dec 31, 2010)

Big, btw. AC working normally dehumidifies air inside in matter of seconds. Is heater core/AC exchange drain plugged by any chance? It's sort of hard to judge by vent air with ambient in 30s, you know... So is AC actually working? Like in - lines are cold and comp kick in?


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## de-nagorg (Feb 23, 2014)

Funny.

I have been dry for 40+ years, And when I am letting my dog out to pee, and I breath on the cold storm door glass it will fog up.

So that theory is shot to hell.:biggrin2::biggrin2:


ED


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## Bigplanz (Apr 10, 2009)

It's definitely a leak. Hazy film appeared on the clear windshield as I was driving this morning. Didn't feel real oily but it was definitely not condensation, as it wouldn't rub right off.

This a bummer. Heater core replacement is beyond my skill set. About a grand, from what I am reading on-line. 7.3 hours of labor, according to Alldata. 

Might just pinch off the heater hose and drive around in the cold for a month. Maybe get through summer, then eff with it in the fall. Mega drag.


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## MTN REMODEL LLC (Sep 11, 2010)

In a heater core... will a radiator stop leak work... should I think.


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## Bigplanz (Apr 10, 2009)

MTN REMODEL LLC said:


> In a heater core... will a radiator stop leak work... should I think.


I have never had any success with that stuff. I will trouble shoot this matter this w/e. Look for obvious leaks, check the AC evaporator drain hole, etc. I will pinch off the hose, probably, since it is late March. Save up the money to fix it in the fall. I don't even have a place to work on it, much less the time and skill and equipment. Oh well.


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## de-nagorg (Feb 23, 2014)

I see that mtn remod has already suggested a stop leak, and you rejected the idea.

I was going to suggest a product named Alumi-Seal, for this.

I have used it specifically for heater core leaks that I described earlier.

It should seal this leak for a while, as long as you remember that this is a temporary fix, and get it in the budget later. 

I have experience changing heater cores, too many over the last 45 years, and would offer my advanced knowledge and ability if we lived closer together, but you can do it, if you want to.

It ain't that hard. I have seen you do much harder things in the past here.

I too would need to study on this particular vehicle 2000 Navigator, but I know that it can be done by the average owner.

Still try a tube of Alumi-Seal, as a temporary remedy, it's better than a foggy windshield every morning.


ED


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## MTN REMODEL LLC (Sep 11, 2010)

de-nagorg said:


> I see that mtn remod has already suggested a stop leak, and you rejected the idea.
> 
> I was going to suggest a product named Alumi-Seal, for this.
> 
> ...


^^^^^^^^^^^^^^^!!!!!!!!^^^^^^^^^^^^^^^^ ED

We are all different people.... I understand.

But I've had good luck with the radiator sealer on several my kids older cars when they were young.

Seems like a good bet to me..... $3 vs $1000 or a long weekend getting to know the intricacies of a Navigator dash disassembly/assembly.


Good luck


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## Bigplanz (Apr 10, 2009)

Seems like I have a bigger problem than I thought. See video.

Coolant all over the street and dripping down the road. Fun times! I need to go get some cat litter or something to soak it up.

Le sigh.


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## de-nagorg (Feb 23, 2014)

With a leak that size, finding it should be easy.

There is no waiting now, it's fix it or risk melt down of the engine when it runs out of coolant.

If it is your heater core, you might b able to install a short piece of pipe in the hoses, inlet to outlet, thus bypassing the core entirely, but do get it fixed.


ED


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## Brainbucket (Mar 30, 2015)

Replacing a heater core is not that bad. It's just a big job. The dash has to come out. They say to take out steering column but I just lay it on the floor and cover it so it doesn't get scratched. Disconnect the electrical connectors. They are all different so it's hard to screw up and connect one wrong. Antenna connector grab it, push it together, twist, and pull apart. Yank out the bolts/nuts that hold it in there and with help put the dash on the pass seat, leaving the drivers side the pivot point, then you have access to the heater/A/C box. If you are changing out the heater core, change the evaporator and accum tank(drier) also. You are already there. A/C recovery is the thing here. Go to a shop the does A/C work. Have them recover you freon and record how much was in there. Then when you have them evacuate and recharge you system, they can use your freon. Read up on it. It's really not that bad.:vs_cool:


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## clarenceboddick (Nov 30, 2016)

Ceramic heaters are pretty good now. If I was designing a car, it would not have a coolant based heating system, unless it was for severe Arctic duty.


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## Bigplanz (Apr 10, 2009)

I went from a little haze to puking coolant everywhere in one day. Hmmm. Well, one thing that is of importance is that when I checked the coolant recovery tank when I first noticed the haze, the tank was near empty. Car was never running hot, going up to 198 or so, then when the t-stat opened, the temp would cycle between 185 and 188.

Still, since the tank was low I added coolant to the tank. Over a half gallon. That's when it puked coolant, right after that. There is no steam, like a leaking hose. When my Villager had a leaking heater hose, the steam was pouring out from under the hood. No steam here, not one whiff. I added coolant, and the car puked it out. Now the car coolant temp is cycling between 190 and 208. The cylinder head temp was 228 and the transmission fluid was 160 when I checked them yesterday afternoon. These are still normal range numbers, but elevated from the previous baseline by about 10 degrees across the board.

This is somewhat confounding. I will put the car on ramps this weekend and get under it with my creeper and a flashlight. I will also clean up the street, since I don't want animals to drink it. What a mess! 

Question: is it normal for the cooling system with the sealed recovery tank (no radiator cap) to puke coolant when it is overfilled? Maybe I put too much in?


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## de-nagorg (Feb 23, 2014)

It is not normal to puke anything.

If it was it would be coming from an overflow at or near the filler cap.

Look around the base of the firewall, for traces of coolant running down it and dripping out, this will show you where the core is dripping from, then follow the trail up the firewall to probably the two connecting pipes for the core.

Or maybe a weep hole to allow any leak to escape before filling up the floorboard.

There's nothing like the smell of a wet carpet and pad with coolant to make you sick.


ED


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## Bigplanz (Apr 10, 2009)

de-nagorg said:


> I
> 
> There's nothing like the smell of a wet carpet and pad with coolant to make you sick.
> 
> ...


That's the other weird part. Carpet is dry, no smell of any kind in the car.

I think I might take the afternoon off to investigate this since it is in the low 70's today and the kids are in school.

Oh, 1st thing I am going to do is pinch off the inlet hose from the engine to the heater core. Going to go out an lunch and pick up a pinch off clamp set at Harbor Freight.

I HAVE to stop this puking coolant everywhere!


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## de-nagorg (Feb 23, 2014)

I have seen them many times crack at the solder joint right where the inlet or outlet pipe is soldered to the actual core, and be spraying out into the engine compartment, instead of dripping into the heater cavity.

Have seen them leak into the cab too, it all depends on the particular vehicles design. 

Back in the old days 50+ years ago, Ford had them easy to change, 6 screws and the hoses, and the whole thing slid out into the engine compartment, then you swapped cores on the plate, and reinstalled.

But now You gotta be a contortionist to get to many of them.


ED


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## jbfan (Jul 1, 2004)

Not that you need this now.


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## Bigplanz (Apr 10, 2009)

I drove it on the interstate, after buying some pinch off clamps. When I was done, the idle temp was between 210 and 215. I went back to the office, let it sit for a couple of hours, put the pinch off clamp on, put some antifreeze in the coolant tank, and drove it around again. Top temp was 191. See attached photo. Clamp seems to do the job until I can come up with a G to get this fixed.


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## Bigplanz (Apr 10, 2009)

jbfan said:


> https://www.youtube.com/watch?v=b5wNf8WX83M
> 
> Not that you need this now.


No video of how long it took to take out the dash. I am sure it is about 1/2 hour, once the dash is out of the way. Shop billable time for this job is 7.3 hours. Me, never having done this, would be about 30 hours plus a nervous breakdown or hulk rage. Somebody who knows what they are doing, probably less than 5. Shop billable hours for this job under warranty is 4.3.


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## jbfan (Jul 1, 2004)

Bigplanz said:


> No video of how long it took to take out the dash. I am sure it is about 1/2 hour, once the dash is out of the way. Shop billable time for this job is 7.3 hours. Me, never having done this, would be about 30 hours plus a nervous breakdown or hulk rage. Somebody who knows what they are doing, probably less than 5. Shop billable hours for this job under warranty is 4.3.


I was quoted between 850 and 1250 to replace mine.

I had a friend that has a shop in his yard charged me 400, and 275 in parts.
97 F150

The last one I did was my old dodge, lay in the floor board and did everything without taking the dash out.


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## Brainbucket (Mar 30, 2015)

It is 7 hours labor for a 2000 Navigator.

*Heater Core*

*Removal and Installation*
*NOTE:* If a heater core leak is suspected, the heater core must be leak tested before it is removed from the vehicle. For additional information, refer to Section 412-00. 


Drain the radiator. For additional information, refer to Section 303-03.
 

Remove the instrument panel. For additional information, refer to Section 501-12.
 

If equipped with the 5.4L 4V engine, remove the junction block splash shield.
 


 

If equipped with the 5.4L 4V engine, remove the bolts and disconnect the cable ends from the starter relay.
 


 

If equipped with the 5.4L 4V engine, remove the junction block bracket.
Disengage the wire harness connector.
 
Remove the bolts.
 
Remove the junction block bracket.
 
 


 

Disconnect the heater core hose couplings. For additional information, refer to Section 412-00.
 


 

Remove the A/C plenum demister adapter.
Remove the screw.
 
Remove the A/C plenum demister adapter.
 
 


 

Disconnect the vacuum line.
 


 

Remove the plenum chamber top.
Remove the 13 screws.
 
Remove the plenum chamber top.
 
 


 

Remove the blend door assembly from the case.
 

Remove the heater core.
 


 

To install, reverse the removal procedure.
Lubricate the coolant hoses with MERPOL® meeting Ford specification ESE-M99B144-B or plain water only, if needed.Copy this as I don't know how long it will be up.:vs_cool:


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## Brainbucket (Mar 30, 2015)

*Instrument Panel*

*Removal*
* CAUTION: Electronic modules are sensitive to static electrical charges. If exposed to these charges, damage may result. *


If equipped with adjustable pedal system, move the pedals to the full forward position.
 

If equipped, remove the front floor console. For additional information, refer to Console - Floor, Front in this section.
 

Remove the passenger air bag module. For additional information refer to Section 501-20B.
 

Position the battery junction box (BJB) power distribution box aside.
Release the mounting tabs.
 
 


 

Remove the bulkhead electrical connectors from inside the engine compartment.
Loosen the bolts.
 
Disconnect the bulkhead electrical connectors.
 
 


 

Remove the bulkhead electrical connector insulator.
 


 

Unclip the bulkhead electrical connectors from the dash panel.
 


 

Remove the lower instrument panel steering column cover. For additional information, refer to Instrument Panel - Steering Column Cover in this section.


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## Brainbucket (Mar 30, 2015)

Remove the valance panel.
Remove the two pin-type retainers and release the expander clip.
 
 


 

Remove the RH instrument panel insulator.
 

Disconnect the restraint control module (RCM) electrical connector.
Release the locking tab.
 
Disconnect the RCM electrical connector.
 
Release the wiring harness locators.
 
 


 

If equipped, disconnect the park brake release solenoid electrical connector.
 


 

Disconnect the electronic blend door actuator electrical connector.
Release the wiring harness locators.
 
 


 

Disconnect the climate control head vacuum harness connector.
 


 

Remove the LH and RH scuff plates.


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## Brainbucket (Mar 30, 2015)

Position the LH and RH door weatherstrip seals aside.
 


 

Remove the LH and RH A-pillar lower trim panels.
 


 

Remove the RH and LH assist handles (31406).
Remove the covers and the bolts.
 
Remove the assist handles.
 
 


 

 *NOTE:* Release the top attachments by pulling inboard first and then upward to release the lower hook. 
Remove the LH and RH windshield side garnish mouldings (03598).
If equipped, on the LH windshield garnish moulding, disconnect the cellular phone hands-free microphone electrical connector.
 
 


 

Disconnect the brake pedal position (BPP) switch electrical connector.
Release the wiring harness locator.
 
 


 

If equipped, disconnect the adjustable pedal motor harness electrical connector and release the locator.
 


 

Disconnect the LH instrument panel main wiring harness connectors and bulkhead connector.
Loosen the bolt.
 
Disconnect the electrical connectors and the bulkhead connector.
 
Remove the LH ground bolts.
 
Release the main wiring harness locators.
 
 


 

Remove the instrument panel steering column opening cover reinforcement (04502).
Remove the nuts.
 
Remove the instrument panel steering column opening cover reinforcement.
 
 


 

Disconnect the electrical connectors.


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## Brainbucket (Mar 30, 2015)

Disconnect the remaining electrical connectors on the steering column.
 


 

Disconnect the transmission range indicator from the steering column.
Remove the bolt.
 
Disconnect the cable.
 
 


 

Lower the steering column (3C529).
Remove the nuts.
 
Lower the steering column.
 
 


 

Remove the instrument panel bolts through the steering column opening.
 


 

Remove the instrument panel reinforcement bolt below the LH corner of the cigar lighter and power point.
 


 

Disconnect the RH instrument panel main harness connectors.
Disconnect the instrument panel harness connectors.
 
Disconnect the inertia fuel shutoff switch electrical connector.
 
If equipped, disconnect the air suspension switch electrical connector.
 
Remove the RH ground bolt.
 
Release all the wiring harness locators from the cowl side panel.
 
 


 

Disconnect the blower motor electrical connector.
 


 

If equipped, disconnect the electronic automatic temperature control (EATC) hose from the evaporator case.
 


 

Disconnect the in-line antenna connector.


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## Brainbucket (Mar 30, 2015)

Remove the instrument panel bolts through the passenger side air bag module opening.
 


 

Remove the instrument panel bolt on the relay bracket.
 


 

Remove the instrument panel reinforcement bolt below the LH corner of the glove compartment.
 


 

 *NOTE:* Position the carpet aside. 
Loosen the instrument panel floor brace.
Remove the upper instrument panel floor brace bolt.
 
Loosen the instrument panel brace bolts and nut.
 
 


 

Remove the RH instrument panel cowl side nut.
 


 

Remove the LH instrument panel cowl side nut.
 


 

On Expedition, remove the instrument panel cowl top bolts.
Remove the covers.
 
Remove the bolts.
 
 


 

On Navigator, remove the instrument panel defroster grille assembly.
 


 

On Navigator, remove the instrument panel cowl top bolts.
 


 

 *NOTE:* This step requires an assistant. 
*NOTE:* Two bullet connectors secure the instrument panel to the bulkhead. 
Remove the instrument panel.


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## MTN REMODEL LLC (Sep 11, 2010)

HEY BRAINBUCKET.....

*What a great post..*...:thumbup::thumbup: can you tell us where you got such detailed explanation.

I don't have a Navigator, just wondered the source for other cars.

TIA


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## Brainbucket (Mar 30, 2015)

https://www.identifix.com It's a Auto tech website for shops. Subscription to get in. I also have Mitchell Pro Demand but I can't copy and paste from that one. If you have a library card, you can use Aldata (Sucks), Mitchell Pro Demand (great), I don't know bout Idenifix (great). Identifix also has what other shops did to fix the problem you are having. It's nice to see what 250 other shops did this to fix the car and it's nation wide.:vs_cool:


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## Bigplanz (Apr 10, 2009)

That's even more complicated than I thought. Sheeesh.

I clamped off the heater hose Friday. No haze on the windshield since then. AC works great (it was 76 Saturday so I had it on). No leaks either. I added some antifreeze after I pinched off the hose, and the temps have returned to normal. 

I will save up to fix this in the fall, since the leak has been stopped. The detailed instructions convince me that a DIY on this is ill-advised. I am sure lots of people could do it, just not me.


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