SOLVED! Fogging on Passenger Side Only

LikeEnvoy

Original poster
Member
Apr 17, 2012
128
Winnipeg, MB
MY 2007 Envoy is fogging up only on on the passenger side, now that winter is here. Never happened before in previous years. The passenger side windshield and all passenger side windows fog up.
Driver's side is fine.
If I select defrost mode, full heat and full fan, with air conditioning on (drying the air), you can see small holes of clear glass appear slowly, but it takes a long time for the fogging to clear across towards the edge of the windshield, and the side windows never clear.
The coolant level in the reservoir tank has not gone down at all, so there doesn't seem to be a major leak of coolant.
Sometimes I think there is a very slight smell of coolant inside when the fan is on full blast ;like this, but most of the time not.
Do you think it is a tiny leak in the heater core? Perhaps small enough that the reservoir level is not obviously going down, but just enough to add moisture to the airflow?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Is there air blowing out of the small side vent in the dash? It doesn't matter where you set the HVAC to blow (floor, defrost, etc.), it always has air coming out of it, both sides. If no air is coming out of it, maybe the small hose that supplies its air is disconnected.

BTW, the A/C will not kick on if it's below freezing. A/C always comes on with defrost no matter if you select A/C or not as long as it's above freezing.

If this checks out, you may indeed have a coolant leak. Do a pressure test to see if it holds.
 
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TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
Either that, or the AC drain hose is clogged, and the heat exchange has a pool of water in it.
 
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LikeEnvoy

Original poster
Member
Apr 17, 2012
128
Winnipeg, MB
Side vents to the door windows- yes, there is good airflow.
Good info about A/C not working below freezing-thanks.
Clogged drain hose - good point.
Don't know how to pressure test the system but will have to wait until warm weather to do any of these now. I hope it lasts through winter.

Thanks both of you for info.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
Living in Manitoba you need good visibility out the windows. Well, you need good visibility no matter where you live, but Manitoba gets a bit nippy during the winter, I imagine. If you don't have a warm place to work on it, I would suggest taking it to a reliable shop and having it looked at. Fogged up windows are a safety issue, and we don't want to lose you!
 

LikeEnvoy

Original poster
Member
Apr 17, 2012
128
Winnipeg, MB
Yes, I had hoped it would stay a minor issue until spring, but it seems like it's getting worse- I can see vapour coming up from the passenger foot-well when sunlight hits it.
Breathing in the glycol vapour is also not pleasant.

I have begun getting estimates to do the job.
Oh well, I've saved a lot doing other repairs, so you can't win 'em all. The garages have nice heated workshops. Oh, perhaps one day I might have a nice, fully equipped, well lit and heated workshop, with plenty of room to walk around, etc. etc.
 
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flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
The garages have nice heated workshops. Oh, perhaps one day I might have a nice, fully equipped, well lit and heated workshop, with plenty of room to walk around, etc. etc.
I dream of the same thing! Right now my work area for our vehicles is the back patio.
 
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Reprise

Lifetime VIP Donor
Supporting Donor
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Jul 22, 2015
2,724
Breathing in the glycol vapour is also not pleasant.
That sounds like heater core, IMO. If you're not detecting leakage now, you may, soon. Check under your mat / carpeting in the front passenger footwell

It's a b!tch of a repair, because you have to take the dash apart / out to get to it.

Keep an eye on your coolant level in the reservoir. If you notice it going down, recheck the front footwell(s).

(on edit): Here in the States, our various auto parts chains will rent coolant pressure testing kits. Net $0, after returning it. You could use this to help pinpoint the leak (no pun intended).
Basically, there's a set of screw-on adapters that attach in place of the rad cap (or the coolant overflow, if you don't have a radiator cap -- but you do). Then a pump attaches to the cap adapter, and you pump it up to 15-18lb or so, and see if it holds that for at least 5min. If you've got a leak, the pressure will start decreasing almost immediately, depending on the size of the leak. While it's pressurized, check for leakage / odor. Also, do all of this when the engine is cold, so you don't burn yourself.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
You being in Winterpeg, I can feel your pain. It's nowhere near as cold here and I have resorted to renting a shop nowadays to do my own work, even if it's warm out.

It really is a biatch of a job. I've done it and it's a really full day job. You'll get sticker shock from the estimates you'll get. It's one of those jobs that you need to get done to survive the winter.
 
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Chickenhawk

Member
Dec 6, 2011
779
There is a new rent-a-space garage in Winnipeg, but this is a huge job. I would not even consider doing it myself.

If you need a recommendation for good garages, let me know. Not cheap but the work will be done right. And, trust me on this one, we have been blessed with a warmish winter so far. When it hits minus 30, you don't want to be driving with a window down just to see and every time you park it, frost will form on the inside.
 
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LikeEnvoy

Original poster
Member
Apr 17, 2012
128
Winnipeg, MB
OK guys, I took your advice and I agree. I booked it in to the GM dealer. I thought, they should know what they are doing at least :smile: Yes, it began to get worse and I was driving with no heat selected and just wrapped up in parka and blanket etc. Fortunately I had the special equipment on board (WIFE- Winter Interval-timed Fogging Eraser), so that helped in the last days.

$1989 later.. it does heat once again and no leaks-Yay! Of course, they had to empty the refrigerant and refill it afterwards too.
They had to use an after market core because GM discontinued it, but should be OK.
The old one had a definite issue in one corner, so I could see where it must have been spraying. Probably the excess was draining through the HVAC drain and not into the carpet- Lucky.
Thanks again to all who weighed in.
Ah, roll on spring.
 

flyboy2610

Member
Aug 24, 2021
460
Lincoln, Ne.
Glad you got it fixed! Getting to the heater core is a big job!
 

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