Help: Overheated and sounding like a boat.. - PeachParts Mercedes-Benz Forum

Turboman · #1 09-30-2002, 08:39 PM

Recently overheated 300CE due to bad water pump. Had pump and tensioner replaced, and immediately upon driving out of shop, the car has a misfire and sounds like a boat. There is also still an overheat issue with no water leak. What can this possibly be?

engatwork · #2 09-30-2002, 09:18 PM

Not good - best case - head gasket, warped cylinder head. Worst case - "relaxed" rings, scarred cylinders$$$.

Turboman · #3 09-30-2002, 09:23 PM

Thanks for the prompt response. Any idea the average cost of each scenario?

MikeTangas · #4 09-30-2002, 11:47 PM

I agree with Jim, sounds like a bad head gasket and head warpage. When you say "overheat with no water leak", how low is the coolant in the tank? A bad head gasket could be dumping coolant into the combustion chamber, losing coolant with no external sign. Check your expansion tank for telltale drops of oil floating on the coolant.

How long did you run it hot and what kind of shop did you visit? Doesn't sound like a MB shop if they turned it out in the condidtion you described.

Turboman · #5 10-04-2002, 06:47 PM

Thanks for the feedback. Just wanted to post an update to the problem. Towed the car to Silver Star Motors in Vienna, VA, and Peter was able to diagnose the problem.

First, the head gasket was fine, apparently changed by the previous owner (I've had the car for about 18 months). Guess, when it overheated, the thermostat was stuck causing continous overheating - should have been changed when the water pump was replaced by the last shop. Then the misfire was coming from a blown valve cover gasket which caused oil to seep into the spark plug holes. Once the thermostat, plugs, and valve cover gasket was changed, the thing runs like a dream again.

Turboman · #6 10-27-2002, 09:26 AM

Since my last post on my overheating issue, and thinking it was resolved, I believe the problem is back to square one.

Even though the car ran great after getting it back from the shop, I am still losing coolant. There are no leaks or white smoke from the exhaust, so I am confident the head gasket is/was the problem. The shop is now quoting me the "regular" cost of repairing the head gasket, even though I went in the first time hinting this may be the problem.

Is there some of the same labor/shop parts involved in replacing the valve cover gasket, replacng the fan clutch, and replacing the thermostat as when one has to replace a head gasket? I am trying to explain to the shop the initial $1000 I paid, should be taken into consideration now as THEY mis diagnosed the problem in the first. Am I wrong here?

engatwork · #7 10-27-2002, 06:45 PM

They charged you a grand to change those few items - wowzer. You need to find a new shop my friend - preferably a good independent in the area.
The valve cover gasket and thermostat most definitely, not real sure about the water pump on this model.
You need to open up cap on the expansion tank and see if there is oil/oily residue in there.