Car smells like exhaust when defroster is on?

syphon

Registered User
I'm not sure if the smell is exhaust. It's not burning oil, not coolant... not exactly gas... but. The best way to describe it is that stale smell that gives you a headache... too much carbon.

Whenever my car is at an idle, or not moving (say a stoplight) the car will smell of it. It's barely noticable, and it only happens when my defroster is on. When moving... I assume enough fresh air is getting in so I dont smell it.

Anyone know what could cause this? Exhaust leak? I wouldnt think that would stink up the defroster... any ideas?
 
If you have auto climate control, I think the A/C comes on with defrost. Perhaps mildew has found its way into the system from lack of consistant use.

Otherwise, maybe signs of egged cats or a strange exhaust leak would be my only other guesses at this time..
 
I dont believe i have the auto climate control... unless it came stock with the '90 SC :) A bad cat could be it... or even an exhaust leak, but I fail to see how that would infect the defroster. It only seems to be coming through the defroster.
 
it is most likely an exhaust leak... it used to do it on my buddys grand marquis...every stop light when the heat was on...it would reak inside....when it was off nothing would get inside...check ur headers or intake manifold...sometime they are noticable...sometimes they are a pain....hope that helps
 
Here's a long shot.... Your car is a 5sp, when you turn the defrost on it sucks air from the passenger cowl inlet vent and you egr pipe is broken, and leaking just enough to get you HIGH, but not bad enough to hear. It is also located on the passenger side manifold. The break and it's probably broken under that fiberglass cover.... look for signs of black carbon indicating a leak

Let us know what you find.
Tim
:D
 
It's an Automatic. But I've also noticed water on the passenger floorboard after rains (water... NOT coolant).
 
if u also what to know if u have a auto climate controll is if u have a digital display....if not i think its the manual. oh yeah same thing happens to me, i get rain on my pass floor from under the dash by the glove box...any one know how to fix this?
 
The rain on your floor probably has the same cause as in the Jeep Wrangler, and probably also had a recall at the time.

There is some seal near the HVAC intake vents by the windshield cowl. I think the surrounding material pulls away from the rubber allowing water to enter the space between.

As you can tell, however, I have not investigaged the problem closely so am not very familiar.. but I believe its along those lines..
 
Cowl seal?

If youre cowl seal is damaged or missing, you will get a lot of air from the engine compartment in your HVAC system.
I forgot to put the cowl seal back on after working on my engine once and it smelled real bad inside the car. The cowl seal is the foam rubber strip forward in vehicle from your windshield wipers.
 
ask me how I know ....

It's probably an exhaust leak on the driver side header. Had the same problem, located and fixed the leak and voila ! Doesn't take much. Could not even hear it.
 
Regarding your exhaust smell no idea.

Regarding the water issue, I too once had this problem. Everytime it rained I would get a nice puddle on the floor, and under the carpet. Here is what I found. Remove the passenger side black plastic windshield cowl. You will notice a rubber gasket that is supposed to keep water from getting between the plastic cowl and winshield thus not letting it dump straight down the fresh air intake. What you will need to do is remove the rubber gasket. Get some RTV, make a nice semi thick(1/4" or more) down the length of this plastic piece paying particular attention to the location of the fresh air duct. I also recall that there is a metal gaurd that runs above the fresh air duct, apply silicone to it also. Let it get tacky, then put the plastic cowl cover back on. Let it set overnight, no more leaks. At least for me dry for over 6 mos, and it rans at least twice a week in New Orleans.
 
Just FYI

Mine did the exact same thing outta the defroster (kinda a moldy pickle smell)
seconds before the head gaskets blew out and stalled the car on the highway.
Engine apart and all the lines look good so i dont know how the two can be related but even still....

Get it Checked out !!
 
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