Engine Cooling problem
1990 Mercedes Benz 300e 6 cyl Two Wheel Drive Automatic
When the car has been sitting overnight it is hard to start & backfires & spits, etc. Once on the road it is fine but if idling at a light it starts shuddering & heats up. It has not boiled over yet but I have been careful to avoid traffic. It has a little over 200,000 miles on it, has been well maintained & the body & interior are in great shape. Recently, had a tune-up, hoses checked & had everything done that was recommended. I am at a loss!