Do you ever get that exhaust smell in car

Every so often I get the smell of exhaust in car not to bad for me but the other half say's it get really bad to her beside pushing her out , I have tried today to find it by putting a whole pack of insence under the car closing it execpt one window with a towel over it and a small 12 volt fan blowing out the half of window with no towel over it, ( trying to creat a small vacumn in car) with no luck I just don't know of a safe way to put lots of smoke under car , or even if thats the right thing to do to find where it's getting in at.. Thanks Tim

my exhaust system seems tight but I know it leaks a little around the collectors on the block huggers . I can feel it

 

Exhaust or blowby from the engine? You didn't say what engine setup you have but if it still has the draft tube and has a bit of blowby you are probably getting some of that inside the car especially when sitting still or driving at slow speeds.

I'm assuming that the exhaust does exit out from under the car and does not dump under the car.
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New collector gaskets are pretty inexpensive and I'd be changing those to start. You have probably had the smell around for months but now you are driving with the windows closed.

 

My 54 has exhaust smells and fuel smells so bad that my wife refuses to ride in it. But I attribute it to a trunk mounted fuel tank and zoomies. My 42 use to get some exhaust fumes in the passenger compartment and I found it was a dried out 67 ish year old seal on the floor access pan and a rusted out exhaust pipe. Replaced it all and have not had a problem since.

 

If you have an exhaust leak inside your car, you are being exposed to CO and thats not good. I would venture to say its likely coming in via the firewall.... Start with the manifold leak and see if that solves your problem

 

Yep carbon monoxide kills - seal that fucker and do everything you can to get rid of the leak.

 

I had changed my intake on my 302 a while back and everytime I'd stomp on it I would smell burnt oil. I looked at the manifold bolts on either side of the carb and there was some residue. Took them out put some thread sealer on em and the smell was gone. Oil was working its way up the bolt and into the exhaust port everytime the oil pressure increased.

 

Use some seamfoam engine cleaner, your motor will puff out more smoke than you've ever seen before. You'll be able to see it billowing out of anywhere in the exhaust system that there is a leak.

 

Fix the leak. Anything else is a bandaid. If there is no exhaust gasses under the car, then they can't get into the cabin. You should be able to hold a wadded up rag over each tail pipe and have it build up pressure. If it doesn't, you have a dangerous leak. You will be able to hear the leak.

 

you want smoke dump some mystery oil down the carb when running do it outside!!!! may not find the car??

usually exhaust leaks are being sucked in the trunk area when moving, exhaust tips far enough back?? seal up body leaks on rear, it is a place of low pressure when driving and exhaust gets in the body

unbolt your collector and stuff some good exhaust sealer in the joints and that should seal that up for good

I have a 1953 chev and have picked up some oil oders in tha car and also had my block huggers spit out a gasget

for your header to block gasgets I have found anti size the best to put on them , try it, it works learned that stock car racing and works for the street too, keeps the gasgets together longer and retork , retork, I hate headders

 

i would go over the firewall first- so many holes, big and small, that may or may not be sealed up... around steering column , heater core, and wiring,,, especially if you think there's a leak at your collector... any carb leaks, oil leaks, breather fumes and header leaks can collect under hood and creep in through the firewall... that's always been my experience except on my cars that had flintstone floors- then it was pretty obvious, and i just kept all the windows open!!!

 

I'd do a complete check of the exhaust system.As previously stated,those fumes will kill you!
With the motor idling,get a helper to hold a rag over the tail pipe to create a little back pressure,while you go under and check the full length of pipe.Any leaks should show up easy.
Make sure the exhaust exits outside the bodywork.
Check for any holes in the body which may let fumes in and plug them.

Of course,you could always get a roadster!
Mark

 

First off, forget trying to find an exhaust leak with smoke. If it's bad enough to smell in the car, then it's bad enough your ear will find it. I'm not even going to mention sealing the exhaust, as that's so fundamental to this problem it shouldn't need to be discussed.

#1 seal ALL holes in the firewall and floor. A 1/8" wire going thru a 1/4" hole is too much of a leak.

#2 be sure your exhaust tip exits outside the body envelope into clean air. Even an inch inside the envelope, expect to smell fumes.

#3 fix any oil leaks that drip onto the exhaust (like weepy valve covers) as the burning oil smell can't be contained and will cause the same eye/nose symptoms as exhaust. It takes a ridiculously small amount of oil to stink up an interior.

Right now it may not be a big deal to you but CO accumulates in your body over time. If you cross the threshold, it's gonna take all automotive joy out of your life for a couple years. Be careful and good luck!

 

If you figure out what's causing it let me know so I can do it to mine. That wife not wanting to ride in your car part sounds pretty good to me.

 

Running a 350 chevy with sanderson headers with the "gasketless" collectors exhaust runs out to the rear bumper I welded a sheetmetal plate over the firewall. but I am thinking it either coming in thru the trunk at speed swirling around the back of the car and I was trying to find where it was coming in the trunk with the smoke so I could seal it up as 35 Chevy were wood framed all the way around the trunk I know I have some gaps that I can not see. I thought I saw smoke I'd shoot some spry foam in the holes...

 

Yikes, no spray foam!

If you gotta clean up stuff like that use autobody seam sealer and don't kill your car.

To some extent though, like idling at a stop with a tail wind..... You're gonna smell a touch of exhaust in a non catalyst car. For somebody that's only driven catalyst cars it might be bothersome.

 

Engine blow-by;crank case vent; cowl vent open ??? Fenderwell headers;outside exhaust headers. ??
All of these things have caused exhaust smell in my hotrods.

Glenn

 

n/m

 

Well I as might as well bring this one back up rather than start a similar thread...

So what would you for the following?

1) Small holes in floor, like someone drilled a hole for something. What is a good long term way to seal it without welding? JB Weld, RTV, Silicone, What?

2) Let's say I have some holes in the firewall that are too big. I got some o rings from Autozone, very sizes. But I think in a few situations, I will still have a gap. What would you use, RTV, silicon, what to finish them off? I see someone used some black stuff at one point for two openings, looks like black RTV to me.

 

Sheesh, a two year old thread... but since Pro Stock John brot it back up...I'd cut some metal pieces and use black silicone to stick them on...or to be safe, silicone it and use a rivet to hold it in place...

Now, before you go to that, it may not be coming in thru the firewall...Ever notice why a station wagon has factory exhausts that exit to the side of the car..and not out the back...???

Because the spent exhaust can swirl around the back while moving and "leak" into the interior via the tailgate and window...same with your car...it may be coming in thru the trunk.

Does it have a good trunk seal...??? Is the trunk sealed off from the interior...??? Is your exhausts down into the airstream...??? Far enuff back from the trunk...???

R-

 

I haven't check the trunk yet, I'm still working on the visible holes that I found so far.

 

yup in my viper and I love it....happens a lot more since i put high flow cats and glass packs in....my hearing hasnt been the same either

 

After I put a louvered hood on a car I could always smell fumes in the cab. Is your hood louvered? Also, trunks are notorious for sucking in fumes and the fumes enter the cab. The only battery I'd stick in a trunk is a gel battery for the same reasons. Vehicles create a draft/vacuum going down the road. Ever wonder why a 60's stationwagon had an air foil at the back of the luggage rack on the roof. It's purpose was to direct wind down against the back of the wagon to blow away exhaust and road dust.

 

No louvers.

I've never used JB Weld before, is that good for sealing holes or would you use RTV?

 

No !

 

I'd use seam sealer.

 

I'll check that out, thanks for the suggestion roddinron.

 

You have a 35 Chev. Typically in the 30's era cars the points where the inner fenders, cowl and floor came together were poorly matched at the factory. There is a lot of gapping there and similarly in the trunk area. Just not very good fit originally. Every penetration through any point in the body, fire wall or floor pan is a possible source. If she notices it more at stop lights I'd start at the rear and work forward. If it is more noticeable at speed then it is coming from the front or there is a low pressure area developing. Is it oily smelling or a rich gas condition or just plain old exhaust from a well tuned engine? I'd sit with her and ask her to tell you what she's smelling and when then look at possible sources. As stated elsewhere tighten up those collectors but I'm guessing that isn't a big contributor.

 

Put a bright shop light under the car and turn the lights in the shop off. Look inside the trunk and see if you can detect any signs of light inside that area. Do the same thing under the hood. Put a light under the hood and close it. With the shop lights off get under the dash and start looking for signs of light leaking through.
Seal all the spots with seam sealer or some other good caulk and then give it a drive to test it.

 

I know this is older thread but I believe I’m on the right track with my fumes in car, ‘40 Ford coupe.....only cruising with windows down! Rolled up, ac or heat on or off nothing, not even normal light gas fumes. Once crack windows I actually get sick after 30 mins with windows, even both all way down, actually both windows open worse. I know there will be people that will try to debunk my theory but I have to say that I have no leaks or cracks in the car because if I did with the windows up I would be creating a death chamber. My wife is very sensitive to smell it when she rides in the car with the windows up she doesn’t even smell a thing as I do. So what I think is happened is recently I changed my rear exhaust tips. I went from what used to be about 4 inches past the bumper to just coming out from underneath the trunk. I asked the previous owner without telling him what I was saying, why he had such long pipes and he told me they used to have short pipes but could not take the fumes in the car so for me I think that 40 Ford is creating a vortex or some type of vacuum and pulling it inside the car with the Windows open so today we’re putting some new longer tips back on because I never had this problem before this.

 

Yep!... I had Cherry Bomb header mufflers on my '69 Z/28 with 2 foot extensions.....