Exhaust fumes when windows up and A/C on - non recirculate mode

[TCurtner]

Help!
Has anyone had experience with exhaust fumes (STRONG!) coming into the passenger cabin with windows up and A/C on non-recirculate? It seems to be worse when going up hill in higher gears (not lugging engine) at slower speeds. With A/C on recirculate do not notice. With windows down do not notice. This doesn't sound safe, any input appreciated.

[repiV]

I can't help you with the cause but I can say that my '05 doesn't do this at all. I drove it last week quite a bit and it was really hot. I had the AC on the whole time in non recirculate mode. I've never smelled exhaust fumes in the car. Exhaust on mine is stock.

Cats plugging up maybe?

[Roddy]

Yep same issue. Was 1000 times worse when catless, now with hfc's i smell it just vaguely, I use the recirclulate setting only. I wish someone could figure this one out. I think it has sonething to do with exhaust fumes being pulled into the fresh air vent near the windsheild at the top of the hood.

Could you possibly have a manifold gasket leak?

[TCurtner]

Yep same issue. Was 1000 times worse when catless, now with hfc's i smell it just vaguely, I use the recirclulate setting only. I wish someone could figure this one out. I think it has sonething to do with exhaust fumes being pulled into the fresh air vent near the windsheild at the top of the hood.

Could you possibly have a manifold gasket leak?

It certainly bears investigation. I need to put a carbon monoxide alarm in passenger seat and see how bad it really is...but i suspect significant. Since i bought the car used have no idea what mods were done, then perhaps undone hastily before trading in (at a dealer). I had an 08 with no mods and never had any issues with this phenomenon.

[FrgMstr]

Just put the top down.

[NMviperguy]

My '04 doesn't do this at all, took it out for an hour long freeway drive last weekend and had no hint of exhaust with the a/c blasting. Definitely sounds like a leak somewhere.

[Vprbite]

Gunked up cats/exhaust components definitely cause a smell. First owner on my car went cat less with mufflers (basically el Cheapo for sound and probably cost power) which was a recipe for a plugged up right side. And to me it smelled like it was about to burst into flames. Replaced with belanger headers, high flows, and corsa (Thanks Jon B!!!!) and everything is better. BUT...I have heard the convertible people say they notice that they got fumes when at a stoplight and the top down and the Gen IV hood cleared it up. though, with a coupe, I run my AC and about two weeks ago had to turn it up cause it was getting too cold in the cabin in fresh air mode, so I definitely wasn't smelling exhaust fumes. And especially not while moving. Something is up. Get it checked out.

If there is a leak at the manifold, you will probably hear a ticking on start up, sort of like a sewing machine. I personally think running cat less is not a good idea and have heard tons of people complain about the stink of cat less exhaust. Even so bad it made people's eyes water. And sitting at a light smelled like a lawnmower at best. so, could be a few things. None of them good or normal though.

[Thom]

On a Gen 3 (and, I assume, a Gen 4) the HVAC air inlet is on the passenger side up near the windshield, but close to the edge of the hood. At least, that's where my memory says it is. Whatever fumes it is sucking in are coming from the engine compartment. Maybe a valve cover oil seepage that's burning on the exhaust manifold, or an exhaust manifold leak. Give the passenger side of your engine a good visual inspection, and try running the engine hood open while looking for any kind of fumes.

[99RT10]

Just put the top down.

He has an ACR coupe, so..........................

[Vprbite]

He has an ACR coupe, so..........................

I think Frg was being facetious.

[jkviper]

My 2001 GTS did this, it was from an exhaust leak on my corsa exhaust. For some reason the clamps did not seal tight. I installed myself so took it to a muffler shop and they fixed it.

[TCurtner]

I cannot tell for sure, but usually an exhaust manifold leak (as you say) is pretty noticeable. I cannot hear one at all! So, this mystery continues. Wife and i doing dragon run tomorrow (see new thread) so i guess we'll either make it...or not :-(
Will let ya'll know. I guess i need a manual, and tear into the system, to see what i can find. I really do suspect that the previous owner probably had belangers and aftermarket exhaust, and pulled them all before trading car. But i hate to ping him to find out - he doesn't know that i know he owned it, and the dealership didn't give me his name/info. I'm just a great Hack! :-)

[Vprbite]

Is it rude to ask? I'm not sure it is. Especially if you ask in a non accusatory manor. As in a "pardon me, may I ask about the exhaust on your pervious car as I ended up the next owner."

It wouldn't bother me.

[TCurtner]

Yes, good point. But i hate to make an entry with a problem.

[TCurtner]

...and, i'd put the top down, but all my hacksaw blades are broken...

[TCurtner]

"On a Gen 3 (and, I assume, a Gen 4) the HVAC air inlet is on the passenger side up near the windshield, but close to the edge of the hood. At least, that's where my memory says it is. Whatever fumes it is sucking in are coming from the engine compartment. Maybe a valve cover oil seepage that's burning on the exhaust manifold, or an exhaust manifold leak. Give the passenger side of your engine a good visual inspection, and try running the engine hood open while looking for any kind of fumes. "
Thom -
Great! - i will begin there in the morning - thanks!

[Vprbite]

Yes, good point. But i hate to make an entry with a problem.

I appreciate your level of respect, and in general that is how we tend to be around here. But I really don't think it's rude to ask. Especially if the person is still a member here. You aren't PM'ing them to accuse them of screwing you, but just to ask to help you diagnose the problem. Perhaps he turned it in with a full aftermarket exhaust and the dealer changed it. Who knows? But I think a respectful question of "what was on there" is not out of line.

[TCurtner]

Went for drive Sunday...verified only comes in when in non recirculate mode. Also inspected exhaust from topside...absolutely no evidence of stock exhaust manifold removal and no audible leaks. If a leak must be past exh manifold or at cat junction or beyond. However there is no apparent audible indication of any leak the length of the car. This car does have the oil catch can mod. Am unaware of how this might contribute, but seems doubtful. Any further suggestions will be welcomed.

[Steve M]

Went for drive Sunday...verified only comes in when in non recirculate mode. Also inspected exhaust from topside...absolutely no evidence of stock exhaust manifold removal and no audible leaks. If a leak must be past exh manifold or at cat junction or beyond. However there is no apparent audible indication of any leak the length of the car. This car does have the oil catch can mod. Am unaware of how this might contribute, but seems doubtful. Any further suggestions will be welcomed.

Any pics of the catch can? Closed or open system (breather or no)?

[Joel]

Thomas

I might try 2 things - the first easy and the second not so much. I would plug the line to the catch can and see if the smell goes away. If there is a leak in the line and it is venting to the under hood air, you could get the smell in the car. Be sure the line is plugged and can't vent. The other thing to do is to remove the sill from the passenger side and drive the car again. It is a bit of a pain to do that as the front upper bolts/nuts are hard to see and remove and there are lots of screws in the sill - nice to have a rack to do it. That would allow you to inspect the exhaust on that side and to drive the car to see if the smell is still there.

[Mr. Bill]

Check your manifold bolts. I just installed Belanger headers on my gen 3 and all but 2 bolts on the passengers side manifold were only finger tight. this might be your problem.......hell I'd suggest that everyone with stock manifolds to check this.

FYI, I never heard an audible leak......but then again one of the first things I did was install the Belanger cat. back exhaust so it was pretty loud.

Now I'm catless with full belanger exhaust and I have no problem with exhaust smell with the windows up and A/C on.

[TCurtner]

Any pics of the catch can? Closed or open system (breather or no)?

IMG_20150629_193941_428.jpgIMG_20150629_193949_717.jpgIMG_20150629_194007_907.jpgIMG_20150629_194030_528.jpg
looks like breather system.

[TCurtner]

Thomas

I might try 2 things - the first easy and the second not so much. I would plug the line to the catch can and see if the smell goes away. If there is a leak in the line and it is venting to the under hood air, you could get the smell in the car. Be sure the line is plugged and can't vent. The other thing to do is to remove the sill from the passenger side and drive the car again. It is a bit of a pain to do that as the front upper bolts/nuts are hard to see and remove and there are lots of screws in the sill - nice to have a rack to do it. That would allow you to inspect the exhaust on that side and to drive the car to see if the smell is still there.

I will report back in a few days, er, months (that could take a while for me) on this effort. Thanks!

[Steve M]

That's an ACR-X catch can system with Arrow modified valve covers - that'd be the first place I'd check for exhaust fumes at this point.

[TCurtner]

Check your manifold bolts. I just installed Belanger headers on my gen 3 and all but 2 bolts on the passengers side manifold were only finger tight. this might be your problem.......hell I'd suggest that everyone with stock manifolds to check this.

FYI, I never heard an audible leak......but then again one of the first things I did was install the Belanger cat. back exhaust so it was pretty loud.

Now I'm catless with full belanger exhaust and I have no problem with exhaust smell with the windows up and A/C on.

All tight!