mcomer78

I have a 2001 C240 with 95k miles. I live in Colorado where the temps in the summer are commonly 95 degrees. If I drive my C-240 for more than 10 minutes or 5 miles and shut it off, and let it sit for about 10 minutes it will not start again. It trys to start, but it seems like it is vapor lock. I use 91 octane and used some octane boost, the problem still exists. It also died at idle at a stop light and would not start again until I let it sit about thity minutes. If I wait about 25 minutes and try restart the vehicle after driving it, it starts right up. My fuel pump seems fine and seems to have pressure when switching the ignition on before I start the car. This definitely seems to be a heat related problem becasue it only happens after the car has been driven for a few minutes allowing the engine bay to get hot, and then problem goes away after it has been allowed to cool off. Any similar experiences or ideas on wat this might be. I will probably just take it in to Littleton Mercedes Bemnz and have them diagnos the problem. Thanks

Tangerine

Seems like you are overheating. Check your temperature readings, see if its abnormal. Check your coolant levels and if the fan turns on or not.

mcomer78

I don't think that is what it is. I just had it serviced (B), and the coolant light did not come one. I als checked the fan after it had been running for about fifteen minutes. It was functioning right. I am at a loss here.

C240-Merc

It sounds like your Crankshaft Positioning Sensor or MAF. I know that I had the same problems that you are describing and it turned out to be my crankshaft positioning sensor. It cost me maybe $200 to bet fixed.