precisionmike

Hello All,

I have a 2003 e55, getting "coolant check level" message. Here is what I have tried...
-Obviously, topped coolant
-Replaced coolant level senor
-Disconnected battery overnight
I have read that the washer fluid circuit is tied into the coolant monitoring
-I have topped the washer fluid

Would I have to clear the fault with STAR or scan tool? If its not that, has anyone had a bad washer fluid level sensor that caused this issue?

Thanks, Mike

phlfly

check radiator for the leaks

precisionmike

Thanks, there are no leaks. The level is good.

Scrapile

Its the float inside the coolant reservoir. Idk if the float gets stuck or comes apart but a new reservoir fixes it. As long as the level is actually no dropping. Unfortunately for you the sensor comes in the new reservoir if I remember correctly. Had this happen a few times.

rapidoxidation

I may be wrong but isn't the transmission cooler built into the radiator on these cars? Get a sample of your transmission fluid and look closely to see if coolant is in there.

gjunon

Is the coolant level decreasing as you drive it? Is there fluid in the underpanels?

your water pump could be getting bad and peeing fluid out of the overflow hole.

gjunon

Just saw where you said you have no leaks. Check the float sensor it may be stuck

ewarwoowar

I had this problem for little over a year with no sign of coolant leaking anywhere and i only had to top it up once a week at most. After taking my car to multiple garages including Mercedes no one could fix the issue. I have had pipes, reservoir tanks, tanks caps and event the radiator replaced and in the end I decided that as the coolant didn't seem to be leaking into any were to cause any major damage that I would just live with it.
Only last month when taking my car for a service the garage noticed that the oil cooler pipe was damaged at both ends. After having it replaced the leak was gone.

Yuille36

How does the oil cooler pipes relate to low engine coolant? Are you talking about the oil cooler that has engine coolant circulating thru it, to either warm up or cool down the oil relative to engine coolant temperature?

ewarwoowar

I don't know i would assume so, but like i said I had tried everything and ever since I got them replaced I no longer had a coolant leek.

Yuille36

You must be talking about the oil heat exchanger, on the right next to the oil filter housing. Because that is the only exchanger that has both oil and engine coolant circulating thru it.