Fumes with the windows open...

[tim jones]

I have a 1990 500SEC FMSH, 99,000 miles in good condition. Does burn a little oil but nothing horrendous. When I open the window I get fumes (not sure if exhaust or engine bay) in the car interior. They seem to 'swirl' in from the outside not through the ventilation system.

I reported the problem and low oil pressure at the last main agent service. They put the low oil pressure down to using Mobil 1 synthetic which when replaced with Castrol Magnatex cured the low oil pressure, but also told me the fumes were due to the Mobil 1 and the problem would now be solved, which it isn't.

Any ideas/suggestions very much appreciated.

Tim Jones

 

[Spike]

Just wondering if the lack of positive pressure in the cabin caused by having the windows open is drawing exhaust fumes in through the louvered vents hidden on either side of the boot behind the carpet. Might be worth just double checking that they are not stuck in the open position.

Failing that, have you checked your exhaust for leaks?

 

[flagstaff]

sounds to me very much as if there is a hole somewhere in a breather hose - from cam cover to air cleaner?

 

[Mikesmerc]

I have the very same problem with my 350sl. If I open the window with the top up it poisons me with exhaust fumes. Close thewindow and all is fine, even with the top down no fumes at all. It must be that negative pressure Spike was suggesting.
Saying all this I dont have that problem with my 90 560sec which has 130k on clock and burns a bit of oil.

Regards
Mike