I have a 1995 C220. Approximately every four to six weeks the low coolant sensor has been coming on and I have been replacing a minimal amount of coolant possibly a couple of cups in the bottle. I have been monitoring the oil level which has been staying the right color and is clear. I have not been able to locate any coolant leaks. I have noticed that there appears to be moisture on the concrete under the tailpipe on the initial startup but I am not sure if this is related to humidity as my other vehicle sometimes does this and is not losing coolant. The water pump was replaced a couple of years ago. I appreciate any ideas.

Thanks

 

OK>if there is no coolant in the oil, which you say there isn't, and it's not leaking on the ground under the car, chances are your engine may be ingesting it through the head gasket.
The moisture in the tailpipe is quite common, and happens in my cars too if they sit for a while, so I don't think that is the giveaway, but.......consider this: IF the head gasket is leaking coolant into the combustion chambers, then it would also be coming out of the tailpipe. So that would be my best guess. I hope it's not, but at least you should check it.
I would do a compression test at the least, but I've found that even some compression tests don't show a minor leak from a coolant passage into the combustion chamber. Maybe it's worth letting an independent shop do that one with some better equipment. Just a thought.

 

Thank you for your response.

This morning I went to open the cap on the bottle and it had such a strong vacuum I had to use both hands to pop it loose. I then noticed that the rubber seals transferred heavy black marks on my hand and upon pressing on them they disentegrated. I am going to try replacing the cap first then will see about a compression test.

Thanks Again

Mike