G Klasse Overheating Mystery Coolant System Issues

Overheating and slow warm-up on an M113 engine often points to the thermostat The integrated map thermostat is a common failure point on those engines Check the thermostat housing for any signs of leakage or corrosion A faulty temperature sensor could also contribute to inaccurate readings, but the extended warm-up time strongly suggests a thermostat issue Consider a coolant system flush during the repair

So, you reckon it's most likely the thermostat then Is there any way to be absolutely sure before I start tearing things apart Also, you mentioned the temperature sensor, where exactly is that located, and how difficult is it to replace if needed

Based on your description, the thermostat is the primary suspect A diagnostic scan might reveal a fault code related to the coolant temperature, but a mechanical failure of the thermostat itself may not always trigger a code The temperature sensor is typically located on or near the thermostat housing While it's possible to replace it independently, given the mileage and the likely need to replace the thermostat, I would advise replacing both simultaneously The repair cost should be around 350€ For a definitive diagnosis and repair, consulting a qualified technician is recommended

I took it to a trusted workshop Turns out it was indeed the thermostat They replaced it along with the coolant, and now the engine is running perfectly, no more overheating Thanks again for your help You were spot on