ARG!!! My cab fogs up badly! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**COBALT** · 12-30-2002, 07:14 PM

I can't get it to clear. It's fogging up like a *****, and of course my heater isn't in good shape.

Anyone have any briliant ideas (non-A/C)?

BobbyK · 12-30-2002, 07:18 PM

I agree,heater core has a hole in it and is allowing coolant into the defroster/heater system causeing the windows to fog like crazy.

Capitol68 · 12-30-2002, 07:31 PM

3 rd it.....heater core

Mudder · 12-30-2002, 07:41 PM

heater core! mine used to blow snow out sometimes too. LOL

**old Rusty C10** · 12-30-2002, 07:47 PM

most likely its the heater core but couldnt it also be the door either locked in the closed position ? or not all the way open check that the control for heat/cool air works if it does heater core

Hooter · 12-30-2002, 08:07 PM

welcome to the wonderful world of an old pickup
I keep a rag in my truck on cold days

Mudder · 12-30-2002, 08:09 PM

Whats really bad when ya have to use de-icer on the inside LOL

lux hauler · 12-30-2002, 08:49 PM

Quote:

Originally posted by Mudder67
Whats really bad when ya have to use de-icer on the inside LOL

lmao.....done that

Alexis · 12-30-2002, 08:55 PM

ever heard of RAIN-X. well they go a product that kills the window fog. i got to say it worked alright. i didnt apply it very well. it was clear in areas i did apply it right and you know the story about the area that didn't. check it out, it like 6 bucks

**COBALT** · 12-30-2002, 09:44 PM

Yeah, I thought about the heater core. It seems like too much moisture is condensing on the inside of the windows. There aren't actual droplets, and I don't smell coolant at all. The heater doesn't even have to be on. The only way I can keep it clear is to crack the vent windows, but of course it's cold out, so...one thing is the defrost ports do heat up the windshield enough to get two nice little holes to look through, but it never completely clears it. It seems like the longer I'm driving the foggier it gets.

I also thought about Rain-x, but if there's a problem I don't want to mask it by using something like that.

....to be continued.

jku72 · 12-30-2002, 10:00 PM

Does not sound like a heater core to me, it sounds like your truck is just normal. My truck does it all the time. My suggestion is to stop breathing when you are driving, and figure out a way to stop the leak in your windshield. I assume this, because every truck I know leaks water in the windshield, leading to high humidity in the cab, and, fog on the windows. What doesnt leak through the windshield leaks down through the cowl.
Or, you could do like me and drive with the window down and your head sticking out the window, but in northern climes be sure to wear chap stick.

mrein3 · 12-30-2002, 10:27 PM

Check your ducts that lead to your defrosters. I used to have a heck of a time keeping my non-AC truck windows clear. The duct work was all ripped apart. I bought and installed new pieces from one of the usual suspects (GMC Paul, LMC, etc.) and it now works much better.

Of course putting AC in will make it better yet. The AC on through the defrosters works wonders when it is wet out.

wcdrake · 12-30-2002, 11:23 PM

I have had the exact same thing happen that your describing and it turned out to be the heater core. At first I didn't smell anything either. The leak was just small enough so there was no smell. Fortunately the leak got bigger and it was obvious. Also I had a kick ass fan and all I could defog was two small peep holes as well. Good luck.

*Shane* · 12-30-2002, 11:56 PM

heater core gets my vote too ....

Lippyp · 12-31-2002, 08:24 AM

I had a heater core let go on a previous car (Think it was one of my Alfasuds) windscreen kept misting up like a b*tch. I ignored it for as long as I could until it finally let go and sprayed boiling hot water out under the dash, fortunately missing anything important on me!

I can't see that it would be the heater core leaking if it is clearing two spots over the vents. more likely just to be old heater syndrome. I would check the heater hoses to the vents, mine were like a lace curtain and replacing them made a huge difference to the performance for a few dollars. Also remove the fan motor and clear out the heater box, it may just be full of crud blocking the airflow, mice may even have eaten the fan itself! Also clear out under the cowl of any old wet leaves etc and clear any drain holes.

My cab is inherently damp, (no garage, English weather, wet feet on the carpet, condensation etc) and my heater clears the screen well, even if it does squeel like a pig! Basically just give the system a thourough check over and clean up first and see if that makes a difference before looking at a new core.

Woody · 12-31-2002, 11:05 AM

Heater Core!!
Just did this yesterday. The 68 I got a few months ago wasn't heating good. I hadn't checked the coolant in it yet. Took off to the recycle center on Saturday and fan belt was squeeling and smoking. Turned around, got back to the house and looked under the hood. Damn! Water pump not turning!!! FROZEN! So after it warmed up I drained everything, flushed radiator, and installed new thermostat (didn't have one in it) and good to go. Then yesterday as I go to the recycle center, the windows fog up, It hadn't done that before.......Looked under truck and found heater core leaking, CRAP, Can you say "froze and cracked!!!"
Called Adv. Auto : new heater core $25 and they had it on the shelf. Installed it last night, drove the truck in this morning and the heater will put you out of the cab. NOT A SIGN OF FOGGY WINDOWS!!!!!

oldsub86 · 01-01-2003, 02:24 PM

Have some advice for you if you do change the heater core. I did mine a few years back and when I took apart the heater core box (for lack of a better description) I found that the factory used a piece of "rubber" to seal the core (or cushion it - who knows ). It was really grungy so I looked for something to replace it. I used a piece of carpet underlay. BAD IDEA. Now everytime it heats up it smells like rubber. I thought it might get better with time but it has not. I will have to take it apart some day and put something else in its place. Don't know if the part is available but it might be worth looking for.

Crank · 01-01-2003, 03:03 PM

I know people on here aren't rich and throwing money away is ignorant but maybe it's worth replacing anyway, if anything you'll have a new heater core for another day. I say replace it and clean out the vents, check the lines, and also clean out under the cowl and hopefully the fog will subside. Good luck
Brandon

**PICKMUP** · 01-01-2003, 04:47 PM

I am fighting the same foggy window problem right now! My new heater core doesn't help, when my new windshield keeps leaking on my new carpet. I had the WS resealed & ran a 110V heater inside for week to dry it...just moved the truck outside to sit in the heavy rain & see what happens. Our WS are terrible leakers, which translates into terrible floor rust if you don't get them sealed...and foggy windows.
1/5/03 Looks OK this time...dry carpet...knock on wood.

**COBALT** · 01-01-2003, 06:42 PM

Thanks for the pointers.

Yesterday I smelled coolant. Since all of the hoses and thermostat are all new and NOT leaking, and my water pump is in good shape I think I know what it is now...

I'll be replacing the heater core this weekend.

**COBALT** · 01-05-2003, 05:38 PM

...put in a new heater core yesterday. The old one had the ever-popular green currosion around the top tube, and it looked like it was bent to fit the holes on the box (???). There were also two spots on the fins where I could see coolant leaking. Guess that must have been the problem.

The box needs some new gaskets badly, and the metal box needed some cleaning, but otherwise it was a piece-o-cake. I had another bee's nest in the box (I had two in each door when I first bought the truck).

LMC sells a gasket kit for $26.

So far ZERO fogging! Thanks guys.

12-30-2002, 07:14 PM	#1
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	ARG!!! My cab fogs up badly! I can't get it to clear. It's fogging up like a *****, and of course my heater isn't in good shape. Anyone have any briliant ideas (non-A/C)? __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

12-30-2002, 07:18 PM	#2
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,769	I agree,heater core has a hole in it and is allowing coolant into the defroster/heater system causeing the windows to fog like crazy. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

12-30-2002, 07:31 PM	#3
Capitol68 Registered User Join Date: Sep 2002 Location: Austin,Tx Posts: 327	3 rd it.....heater core __________________ '68 Fleet LWB orig 307 .030 over GM Hei/w Accel Super coil orig. stock TH 400. _______________________ “What we do for ourselves dies with us. What we do for others and the world remains and is immortal.” Albert Pine English author d.1851

12-30-2002, 07:47 PM	#5
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,275	most likely its the heater core but couldnt it also be the door either locked in the closed position ? or not all the way open check that the control for heat/cool air works if it does heater core __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

12-30-2002, 08:07 PM	#6
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,078	welcome to the wonderful world of an old pickup I keep a rag in my truck on cold days __________________ MEMBER DISCS UP FRONT CLUB 69 custom camper/cst 10 70 monte carlo 383 stroker with a 700r4 77 fully loaded silverado (back in the backyard for a little while longer) 1980 BMW 320i (back in the garage finally) 1981 f@*d f150 4x4 (Robert red ford) tried to kill me 1972 Honda ct 90 trailbike Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com AC/DC RULES!!! First generation Monte Carlo club pictures of my life

12-30-2002, 07:41 PM	#4
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	heater core! mine used to blow snow out sometimes too. LOL

12-30-2002, 08:09 PM	#7
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	Whats really bad when ya have to use de-icer on the inside LOL

12-30-2002, 08:55 PM	#9
Alexis Member since 2000 Join Date: Dec 2000 Location: Mountain View Ca / Mexico Posts: 7,879	ever heard of RAIN-X. well they go a product that kills the window fog. i got to say it worked alright. i didnt apply it very well. it was clear in areas i did apply it right and you know the story about the area that didn't. check it out, it like 6 bucks

12-30-2002, 09:44 PM	#10
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Yeah, I thought about the heater core. It seems like too much moisture is condensing on the inside of the windows. There aren't actual droplets, and I don't smell coolant at all. The heater doesn't even have to be on. The only way I can keep it clear is to crack the vent windows, but of course it's cold out, so...one thing is the defrost ports do heat up the windshield enough to get two nice little holes to look through, but it never completely clears it. It seems like the longer I'm driving the foggier it gets. I also thought about Rain-x, but if there's a problem I don't want to mask it by using something like that. ....to be continued. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

12-30-2002, 10:00 PM	#11
jku72 Registered User Join Date: Jan 2002 Location: cornville, maine Posts: 659	Does not sound like a heater core to me, it sounds like your truck is just normal. My truck does it all the time. My suggestion is to stop breathing when you are driving, and figure out a way to stop the leak in your windshield. I assume this, because every truck I know leaks water in the windshield, leading to high humidity in the cab, and, fog on the windows. What doesnt leak through the windshield leaks down through the cowl. Or, you could do like me and drive with the window down and your head sticking out the window, but in northern climes be sure to wear chap stick. __________________ jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers

12-30-2002, 10:27 PM	#12
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,253	Check your ducts that lead to your defrosters. I used to have a heck of a time keeping my non-AC truck windows clear. The duct work was all ripped apart. I bought and installed new pieces from one of the usual suspects (GMC Paul, LMC, etc.) and it now works much better. Of course putting AC in will make it better yet. The AC on through the defrosters works wonders when it is wet out. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

12-30-2002, 11:23 PM	#13
wcdrake Registered User Join Date: Jul 2002 Posts: 14	I have had the exact same thing happen that your describing and it turned out to be the heater core. At first I didn't smell anything either. The leak was just small enough so there was no smell. Fortunately the leak got bigger and it was obvious. Also I had a kick ass fan and all I could defog was two small peep holes as well. Good luck.

12-30-2002, 11:56 PM	#14
Shane Account Suspended Join Date: Jun 2000 Location: over yonder Posts: 14,270	heater core gets my vote too ....

12-31-2002, 08:24 AM	#15
Lippyp English Chevy Owner Join Date: May 2002 Location: Shropshire, UK/ Lot, France Posts: 1,848	I had a heater core let go on a previous car (Think it was one of my Alfasuds) windscreen kept misting up like a b*tch. I ignored it for as long as I could until it finally let go and sprayed boiling hot water out under the dash, fortunately missing anything important on me! I can't see that it would be the heater core leaking if it is clearing two spots over the vents. more likely just to be old heater syndrome. I would check the heater hoses to the vents, mine were like a lace curtain and replacing them made a huge difference to the performance for a few dollars. Also remove the fan motor and clear out the heater box, it may just be full of crud blocking the airflow, mice may even have eaten the fan itself! Also clear out under the cowl of any old wet leaves etc and clear any drain holes. My cab is inherently damp, (no garage, English weather, wet feet on the carpet, condensation etc) and my heater clears the screen well, even if it does squeel like a pig! Basically just give the system a thourough check over and clean up first and see if that makes a difference before looking at a new core. __________________ Phil '67 C10 long fleet. 350/TH350, 4 bbl Carter, K&N, Dual exhaust, loads of stuff coming soon 2001 S10 Blazer Daily Driver, bone stock 4 door 4x4 with manual transmission

12-31-2002, 11:05 AM	#16
Woody Registered User Join Date: Feb 2000 Location: Georgetown, KY, USA Posts: 631	Heater Core!! Just did this yesterday. The 68 I got a few months ago wasn't heating good. I hadn't checked the coolant in it yet. Took off to the recycle center on Saturday and fan belt was squeeling and smoking. Turned around, got back to the house and looked under the hood. Damn! Water pump not turning!!! FROZEN! So after it warmed up I drained everything, flushed radiator, and installed new thermostat (didn't have one in it) and good to go. Then yesterday as I go to the recycle center, the windows fog up, It hadn't done that before.......Looked under truck and found heater core leaking, CRAP, Can you say "froze and cracked!!!" Called Adv. Auto : new heater core $25 and they had it on the shelf. Installed it last night, drove the truck in this morning and the heater will put you out of the cab. NOT A SIGN OF FOGGY WINDOWS!!!!!



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01-01-2003, 02:24 PM	#17
oldsub86 Registered User Join Date: Dec 2002 Location: Canada Posts: 695	Have some advice for you if you do change the heater core. I did mine a few years back and when I took apart the heater core box (for lack of a better description) I found that the factory used a piece of "rubber" to seal the core (or cushion it - who knows ). It was really grungy so I looked for something to replace it. I used a piece of carpet underlay. BAD IDEA. Now everytime it heats up it smells like rubber. I thought it might get better with time but it has not. I will have to take it apart some day and put something else in its place. Don't know if the part is available but it might be worth looking for. __________________ 1968 Chevy - 292 with a powerglide

01-01-2003, 03:03 PM	#18
Crank Registered User Join Date: Aug 2002 Location: Crittenden, KY Posts: 1,964	I know people on here aren't rich and throwing money away is ignorant but maybe it's worth replacing anyway, if anything you'll have a new heater core for another day. I say replace it and clean out the vents, check the lines, and also clean out under the cowl and hopefully the fog will subside. Good luck Brandon

01-01-2003, 04:47 PM	#19
PICKMUP "Trucks with Class" Join Date: Jul 2000 Location: OLYMPIA, WA, USA Posts: 8,122	Soggy Bottom I am fighting the same foggy window problem right now! My new heater core doesn't help, when my new windshield keeps leaking on my new carpet. I had the WS resealed & ran a 110V heater inside for week to dry it...just moved the truck outside to sit in the heavy rain & see what happens. Our WS are terrible leakers, which translates into terrible floor rust if you don't get them sealed...and foggy windows. 1/5/03 Looks OK this time...dry carpet...knock on wood. __________________ Email: frankeham@comcast.net Phone: 360-956-7170 Last edited by PICKMUP; 01-05-2003 at 08:27 PM.

01-01-2003, 06:42 PM	#20
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	Thanks for the pointers. Yesterday I smelled coolant. Since all of the hoses and thermostat are all new and NOT leaking, and my water pump is in good shape I think I know what it is now... I'll be replacing the heater core this weekend. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

01-05-2003, 05:38 PM	#21
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	...put in a new heater core yesterday. The old one had the ever-popular green currosion around the top tube, and it looked like it was bent to fit the holes on the box (???). There were also two spots on the fins where I could see coolant leaking. Guess that must have been the problem. The box needs some new gaskets badly, and the metal box needed some cleaning, but otherwise it was a piece-o-cake. I had another bee's nest in the box (I had two in each door when I first bought the truck). LMC sells a gasket kit for $26. So far ZERO fogging! Thanks guys. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

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