I turn on the vents and the cabin fills with exaust fumes during idle. Driving makes the smell go away. Happens in all settings. Help......

The car is a 1988 560sel. The fumes come in the cabin during idle. The smell comes in by the vents (all settings). Driving makes the fumes go away. Help.......

it sounds like you have an exhaust leak near the front of the car. check all exhaust connections. with the engine cold, start the car and feel for exahaust pressure at all exhaust connections. do not touch the manifold or any of the pipes, just hold you hand near the connections. feeling for leaks is often better than listening when the leaks are small. often times you won't hear them over the engine noise or you won't be able to tell where they are. if it is an exhaust leak: tighten the connection, weld the crack, or replace the part that is leaking.

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dew
86' 190e 2.3L 16v

also check the seal(hood pad) in the engine compartment.
if this is bad you get smells sucked into the car.

How would a bad hood pad cause exhaust fumes to get sucked into the car? Doesn't all the exhaust get tunneled out the back anyway?

On top of the valve cover there is a hose that goes to the air filter. The hose was cracked and fumes would come out and go into the cabin from the vent inlet.
This problem took about 5 months to track down. I had to go on the freeway and take off the filter housing to see smoke come out from the valve cover.

Luck

Nick Mendoza

It is possible the fumes are coming in through the trunk. Check to see if the trunk is closing tightly. The bolts which hold the lock have a habit of coming loose.

The heating system has an inside air and outside air setting. The outside air I believe is 20% mixed with 80% inside air. The inside air switch should toggle to 100% inside air. If this does not get rid of the smell, you could have a bad diaphragm that blocks the outside air. This diaphragm is located behind the glove box.

This might be slightly off subject, however if this is working properly it will help with your process of elimination.

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David
1988 560SEL, Green, Chrome wheels.
2000 Suburban, 20" wheels, DVD, wood grain dash (wife's car).
67 Beetle euro, Lots of Empi parts.
69 Beetle conv, 1980s cal look.