C3504M

The CE light came on, on our 2010 ML 550, P0128, which was thermostat or coolant temperature.

I have not had a chance to have it looked at or check if it's just low coolant.

Is the car safe to drive in the meantime?

Also how do I check the coolant level? If that's all it is what type of coolant should I buy?

Other thoughts?

Plutoe

I think it is safe for around town trips-------you check the coolant by reading your manual which will tell you to observe the cold coolant level in the coolant expansion tank---if you don't know where that is go no further-----stop any kid on the street and ask ----he will ask you to lift the hood and point to it------if you live in a restricted community go to a dealer!!

ml3204me

P0128 simply means that your coolant temperature is not reaching the desired temperature in the recommended time. It is staying cooler than it should. Doesn't hurt the engine. But you will experience cold to warm air if you need heat in the car.

Check out this video on replacing the thermostat: