1998 Mercedes-Benz SL-Class - exhaust smell can't be explained

Why does the car have an obnoxious exhaust smell?

Most likely because you have an exhaust leak and you should have a muffler shop fix it .


Thanks but a check by a facility says no exhaust leak.

What ever this ’ Facility ’ is did you not have them try and determine what you are smelling . Did they notice the smell which may not be exhaust ?

Nah they insisted there was no smell , no exhaust leak and at that time there wasn’t due to the draft of air in the facility. Meineke it was.

Stay away from meineke & other chain store’s & find a indepenet shop.

OK, back to the original statement, find a real muffler shop . There may a Meineke place that can do something besides oil changes but I have never seen one.

Two independents couldn’t find an issue either, that’s why I’m searching the folds of others.

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Are you sure it’s an exhaust smell? Could it be an oil leak dripping onto an exhaust header or pipe? Lots of possible oil leaks on a 21 year old car.

Define obnoxious. Does it smell like rotten eggs, by chance?

No it’s the usual exhaust smell, oil, etc.

I thought that as well, the only oil spill I had was from the last oil change. The “techs” had not cleaned up. I had them clean my driveway and the whole engine bay top and underneath.

Smell still remained, more so on starting up and stopping.

Your mechanic should check under the exhaust header heat shield. The header can crack there, and then the exhaust gets sucked into the vents for the air conditioner. Best of all, sometimes once the car warms up, the header gets hot enough to seal the crack via thermal expansion, and so when someone goes to look they don’t find the leak.

Also,check your rubber door seals because they can crack with age and allow exhaust fumes to enter the cabin.

Has anyone used a combustion gas detector to examine every inch of the system when running, both cold and warmed-up?

I’ll have that checked out.

Many thanks


I have the top down most of the year, having said that when the hard top is on interior odor does not appear.

Thanks for the thought though.


Not to my knowledge, I’ll put that on the list.



Have you changed gas stations? Especially true if you live in the Eastern part of the US, where the amount of sulphur in the various vendor’s gasoline can vary quite a bit, vendor to vendor. If you live east of Denver, try using a different gasoline brand, see if that makes a difference.

Thanks George, I live in AZ, after 6 months in TN and before that 40 years in CA after a year in TN.

Same old smell and started when I lived in the Bay Area…now isn’t that funny?