Exhaust smells when windows or hard top down

[daz10dazza]

Hi all, Has anyone come across the same situation as me ? My 300SL really smells when I either have my windows open and roof on or with the roof down. The boot absolutley stinks of exhaust fumes. When I purchased the car the current owner had a custom fit full stainless exhaust fitted by Longlife. The tail pipe is short and stumpy and has a 90 degree bend from the back box so it faces down and isn't visible from the outside of the car. A friend of mine whos a mechanic suggested because the way the pipe is facing downwardes this will allow for exhaust fumes to not discharge properly from the back of the car. Does this make sense to anyone or could there be something else ? Thanks

 

[Myros]

it's all about the aerodynamics

the 107 shape definitely pulls exhaust fumes up into the area between the boot lid and the exhast pipe ( outside). All you have to do is look at your SL after a good long drive and you might see some discolouration/sootiness on the left hand light cluster. If you look at older 116s and SLs you see some of them almost have a gold reversing light courtesy of all the oily fumes drawn past it.
If you have the windows down, (top on) you create a low pressure zone in the cabin, this draws air out of the boot courtesy of the soft top chamber, which communicates with the boot by the holes for the boot struts and the deck struts. If you have any faulty seals anywhere on the boot or the drainage holes, or a bad panel-fit, or a rust hole near the exhaust, fume-laden air can be drawn into the boot, and then the cabin as a result. If you have the lid off, the same thing can happen, as you create a really low pressure zone in front of you with the airflow over the screen and into the cabin.
So, if you have faulty seals and a leaky exhaust, you will gas yourself quite well. At a standstill, you could easily have a build up of fumes strong enough to affect you. I suggest getting the car to someone who can test the exhaust for leaks, and pronto. The rear tailpipes are supposed to angle down at about 45 degrees, either bent, or having baffles and cut-outs in straight pipes. I'd check your boot seals and panel fits as well. and hold your breath at the lights.

 

[daz10dazza]

Thank you very much. I'll check eveything you have mentioned. My car goes in for a service next week so I'll ask the chap to check these out. Thanks again, it is appreciated.