I have a

1992 Mercedes 500E VIN number WDBEA36E4NB641329

Eng: 303_ CID _4973CC_Gas Mileage:168,257 5 liter, V8

This is a federal car ( no engine warning light on the dash). I am having a problem with my car not restarting after it is turned off. It doesn't happen all the time, but it is more frequent than it used to be and the mechanics at the authorized Mercedes dealership seem to be stumped. The car runs fines, other than this problem. This seems to occur only at a certain temperature (approximately 180 degrees). I took my car in to the dealership regarding this problem and I paid for the diagnostic testing and they advised that I get a new air mass sensor and EACC Motor. I took it in on for these parts to be changed on August 4, 2005 ($1600) and picked up my car on August 9, 2005. I had it for 20 minutes (approximately 5 miles) and the problem was still there, so changing those parts didn't address the problem. I returned my car on August 10, 2005. They said they couldn't get it to fail. They had it until September 20, 2005. They still couldn't get it to fail. I picked it up and the problem was still there. This time I was able to drive it into their shop and it failed in their presence on September 21, 2005. All of the mechanics were gathered around discussing the situation. I'm not sure if they were able to gather any useful data from their computers at that time, but they kept my car until October 14, 2005. When I picked it up on Friday October 14, 2005 they said they put on 2 new distributor caps, 2 rotors and 2 coils. They wanted me to drive it over the weekend to test it. It failed again. It's back at the Mercedes dealership. The people at the dealership have been very courteous and have provided me with a loaner vehicle, but they are stumped.

Usually I have to wait 20 minutes or so for it to cool down and restart. During that time the motor turns over, but it never starts. This is very frustrating, particularly at gas stations. In the past couple of years, these other components have been replaced:

camshaft sensor
crankshaft sensor
ignition computer box
coolant level sensor (#124-540-02-44)

I would appreciate any advice?

Thank you,
Prostock70 gtofarm@aol.com

I know the coolant level sensor has been replaced - but what about the coolant temp. sensor? I don't know why but I keep thinking with problems at that specific temp. it has to do with that sensor.

They changed the coolant temperature sensor Friday afternoon and I got my car back Friday evening. So far I've had no problems. I hope this is it. Thank you for your input, Benzboy87. I really appreciate you taking the time to respond.

Prostock70