I have a 92 300e.......... Had the head gasket done 4000 miles ago.......... it seems that when I cut the car off I get a little coolant that drips from the expansion tank.......... is this common also when starting the car the temp guage goes up and then drops quickly to normal......
thanks

If the temperature gauge goes up fairly quickly after starting to a point well above normal operating temperature - and then drops back down to normal, that is a symptom of a "sticky" thermostat.

It will steadily get more sticky, and puts some stress on the engine. Better to go with a replacement thermostat.

But remember, this is an Internet diagnosis - I can't really see what you are referring to - only what has happened to me on other vehicles.

Where is the coolant leaking from on the expansion tank? Is it an overflow out the top? Or one of the pipes leaking?

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

What is the coolant level in the expansion tank when the engine is stone cold; parked on a level surface? Perhaps it's cold level setting is too high to begin with?

Perhaps the expansion tank is over-filled? Otherwise it should never come out the top.
I suppose there could be a leak in one of the hoses, or the tank itself.

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1986 300E 5-Speed 240k mi.

...or the coolant tank cap isn't screwed on completely?

There are two sets of detents on the tank lip. If the cap isn't securely tightened past both sets of detents, you have insufficient tank pressure and it will manifest itself by trickling out when shutting off the engine.

Are your hoses collapsed when you shut down?

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car