1995 Mercedes E320
Mileage: 128,000


We're having a problem with our 1995 Mercedes E320. It's seemingly an intermittent problem with exhaust-like fumes entering the cabin. The fumes were so noxious that we've had terrible headaches and neckaches. It's so bad that neither of us is willing to drive the car.

Our regular Mercedes shop and the dealership service department have told us that they cannot duplicate the problem. They have assured us that we do not have an exhaust system leak and that our emissions system is functioning properly. Further, they've told us that given the way the car is designed there's almost no way for fumes to get into the cabin.

We're at our wit's end and need help from someone.

Here's a summary of what's been done to the car recently:

7/25/08 - Regular Mercedes shop drove the car for several days, but could not duplicate or detect the problem with fumes. Read and cleared codes, cleaned MAF sensor, cleaned intake and added fuel treatment to tank.

8/14-20/08 - Regular Mercedes shop drove car for several days, but again was unable to duplicate or detect the problems with fumes. Replaced mass airflow sensor and air filter.

8/23/08 - Girlfriend drove the car on a short morning trip, and while stopped at a stoplight was suddenly overwhelmed with what could be described as exhaust-like fumes coming from the front of the cabin and exceptional heat radiating from the front floorboard and center console area. Girlfriend became ill with symptoms including headache, muscle ache and extreme nervousness. I drove the car on several trips around town later that afternoon, but did not observe any further problems. We parked the car outdoors overnight.

8/24/08 - I drove the car with girlfriend in the passenger seat hoping to duplicate and observe the same condition she had observed the previous day. We drove the car on several stop-and-go trips. During the third trip, the check engine light came on after about five minutes. Though no other symptoms were observed, we decided to drop the car off at regular Mercedes shop, hoping the codes would offer some insights into the problem.

On the way, suddenly the overwhelming exhaust-like fumes came flooding into the cabin and exceptional heat began radiating from the front floorboard and center console area. I stopped the car and had girlfriend get into the car to confirm that this is what she had experienced the previous day. Driving the short distance of less than a mile made me ill with immediate symptoms including headache, aching muscles, difficulty concentrating, and irritabilitydespite that I had opened the windows and sunroof at the first sign of a problem and turned off the air conditioning.

8/25/08 - Regular Mercedes shop said they could detect no fumes. They reset codes and used Power Clean fuel cleaner. Regular Mercedes shop said that if this didn't work, that we should take the car to the dealership service department.

I have put no more than 50 miles on the car since picking it from regular Mercedes shop. Each time I have driven it since, I've experienced noxious fumes and the symptoms outlined above.

The Mercedes dealership has had the car for observation and diagnostics for a week and cannot duplicate the problem.

Clearly, this problem is intermittent, but it is very serious. Have read through hours of posts on various forums, but nothing quite fits our problem.

 

95 m104 have they inspected the rear of the head for oil leaks common to that engine,also the front pass side and the timing cover.Oil leaking down onto hot exhaust would flood the cabin with fumes till burned off and then again when enough gathered to pool up and drip again.
ohlord

 

Thanks for the prompt reply. The head gasket was replaced within the last year.

The dealership says there's one drop that drips every once in a while (can't remember where they said it was leaking from) but hardly enough to detect, but it's not hitting the exhaust manifold. Also, the fumes are more like exhaust fumes rather than the burnt oil smell. I may ask them to revisit this if nothing else shows up.

Thanks for your insights.

 

Here's an update on our problem E320:

After nearly two weeks with the dealership service manager, who could never duplicate our symptoms, I brought the car home and drove it on short trips around town with no obvious problems for nearly a week.

Then, on Friday evening on the way home from the office, the phantom fumes returned during a trip of fewer than two miles. The fumes began to affect me almost as soon as I pulled out of the parking space and the check engine light came on.

Monday morning I took the car directly to the dealership. The codes returned indicated an oxygen sensor malfunction and a problem with the upshift delay switch over valve. The dealership doesn't think these have anything to do with problem with fumes.

So far I've been more impressed with possibilities folks here on the forum have come up with than with the ideas from the dealership.

Does anyone have any other ideas, now that we know what the codes indicate?

 

the dealership doesn't think the O2 sensor failure has anything to do with this? what dealership is this?

 

They maintain that even if the 02 sensor is causing the car to dump fuel the fumes would not wind up in the cabin because the cabin air intake is "sacrosanct" so to speak.

So far, they've never been able to explain how fumes are getting into the cabin because they cannot detect any fumes.

This is the most frustrating problem I've ever encountered.