2012ml550

My new 2012 ml550 runs only 4700km and coolant low warning message has appeared twice, one around 2000 and one around 4500 and disappeared itself after a few minutes drive each time. I also noticed there are fresh water marks on the ground it was parked. Add coolant and suspect coolant leakage. Can't believe it happens to my new ml.
Booked appointment with dealer to have it checked this week.

Otherwise it is an awesome car though.

YYZ-E55

Possibly no cause for alarm. The water is probably from the AC condensor, and the low coolant light is likely going away because the fluid expands when it warms up. The coolant level simply may not have been filled enough from the factory.

2012ml550

dealer topped the coolant level to the max when the warning message appeared for the first time. Then after around another 2000km, warning message appeared again. Visually checked the coolant level, it was really lower than the top. So I added coolant myself before sending it over to dealer to check the leakage. Not sure if the water is from AC but hope so. However some coolant was lost for sure in a short period of time.

katiesdad7

Check the oil dipstick to see if coolant is in the oil.

300DTurbo

doesn't the 550 have a known HG issue?

2012ml550

Here is an update from my dealer: they came back and didn't find any leakage after visual checking and pressure tester."RAISED VEHICHLE ON HOIST RE AND RE THE LOWER ENGINE COVERS NO LEAKS DETECTED AT THIS TIME. PRESSURIZED COOLANT TO 1.5BAR WHILE INSPECTING FOR LEAKS. NO LEAKS DETECTED AT THIS TIME. WITH PRESSURE TESTER CONNECTED FOR ABOUT 15MIN PRESSURE DID NOT DECREASE STAYED AT 1.5BAR".

2012ml550

KATIESDAD7, how to see coolant in oil? coolant is basically water..... thanks,

2012ml550

hi 300DTurbo, what is the HG issue? I am new here.... thanks

2012ml550

found answer myself. Head Gasket... thanks,

dgiturbo

Here is my guess. For some reason these turbocharged engines trap an air bubble somewhere in the system when factory filled, that slowly works its way back to the reservoir, causing the lower level and light.
My diesel ML did this exact same thing about 3 or 4 times within the first 6 months, usually after I parked and the night got cold. Never since. Back then I just topped it up with about half a cup of coolant each time.
If MB pressure tested and it held, and you are not having overheating issues, your good to go.
And like YYZ-E55 said, the water you are seeing is probably going to be from the air conditioning. Touch it and see if it feels "oily" (coolant) or it's just water.

2012ml550

Thanks dgiturbo! you gives me a peace of mind of such instance.....maybe just water came out from A/C and never have overheating.

Thanks and I love the forum from my heart.

luffy09876

I apologize for bringing up this old thread. I had a similar issue with my vehicle recently, the radiator coolant was mysteriously getting low, as I further check, the hoses, cracks in radiator or head gasket but there is no sign of leakage, and it turns out that my radiator cap was damaged and it’s not holding the standard operating pressure anymore and I immediately replace it. I came across an in-depth article that may be worth reading. Search for "Mercedes-Benz Check Coolant Level Warning Light on YOUCANIC" and you will see an article that goes over common causes and possible fixes. You can read about it yourself. I hope this information can assist someone else with a similar issue.