Hey Y'all,

I want to know if anyone has had any sort of exhaust leaks or exhaust coming into the cabin through the HVAC system?

I've noticed an exhaust smell coming into my HHR the last couple of times I have driven it.

The exhaust smell becomes apparent when the HVAC is set to vent. Setting it to recirculate does not allow any more exhaust smell to come into the vehicle. It also is only apparent at low speeds or when I am stopped and sitting idle (traffic light or whatever.) I've ruled out it being from other vehicles because it happens when I idle without any other vehicles running.

Can anyone tell me if there is anything I can check myself to try and pinpoint this problem or should I just have it examined by a mechanic?

In case it matters, my HHR is 4 years old and has just under 60,000km (37,000 miles.)

Thanks.

 

I really can't offer anything at this time, Calgary. But it does seem strange that you experienced the exhaust "smell" when using the HVAC vent, since it pulls the outside air from in front of the windshield cowl area. This would probably suggest something may not be correct in the exhaust system under the hood......and possible to the downpipe.

 

That's one of the things that really seems strange to me as well. The exhaust gases would have to get sucked in from above the hood.
Maybe it is a bad exhaust manifold seal?

 

If it was an Exhaust Leak wouldn't it be Audable? Most of the times that I have had any type of Exhaust Leak I could Hear it before I Smelt Anything! Maybe even a Cabin Filter Change Out ?

Good Luck and Let Us Know what the Dealer Says ,

 

My cabin air filter was changed at the beginning of summer (about 4 months ago.) I will take a look at it though to see if something doesn't look right.

 

I'm thinking the smell could be coming from the heater / A/C duct's ??? On my 96 Blazer the dealer flushed the duct with something GM sells just for this smell ????

 

Just had a thought to check on the smell being exhaust ??? A good hardware store sells those little stick on test badges for carbon monoxcide ?? Put one on the console and watch it to see if it changes color ????

 

I was thinking about stopping in a store to pick up some sort of carbon monoxide detector to see if it picked up large quantities of CO.

I previously did have a problem with a bad smell coming from my HVAC system but it was more a moldy, musty smell. That was finally dealt with by having the service department install an afterblow module. Every now and then I spray some Lysol into the cabin air intake (just below the windshield on the drivers side) and let the HVAC vent settting run on high for a few minutes.

This is a much different problem/smell.

 

I will be taking my 06 in for the same problem this morning.
it seems to me that there is a back pressure or leak in front of the converter
that is filling the engine compartment with exhaust and then is being drawn back into the hvac system. I will let y'all know what I find out.

 

Calgary......

What isthe outcome on this???

On further thinking.......

Carbon Monoxcide should not smell....remember it's the "silent killer". So maybe the odor is coming from after the converter....the sulfur/rotten egg smell? Just a thought.