OM651.930 engine temp running low

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New Member
May 7, 2023
CLA 220D AMG Sport

Got a CLA220d with the 2.2 om651.930 engine, it has around 70k miles on the clock and has been a very reliable car up to now.

The engine temperature runs at 60 degrees, it used to run around the 80-90 degrees c mark. It seems to have gradually done this over a couple months. It sat at 70 for a few weeks and now hovers at 60. There is heat getting into the cabin from the heaters so I don't believe it's air lock related.

When driven in a 'spirited' manner OR sat at idle, it does rise up to the 80-90 and get to temperature then drops back to 60 degrees when driven normally. I don't think it's sensor related as the sensor reads the temperature going up and down and shows it on the dash.

Is it likely to be thermostat related? I have heard that the water pumps on these are electric and regulate flow, is this true? There are signs of mouse damage underneath the engine cover... I'm hoping they haven't chewed through a wire that leads to a sensor or pump that regulates temperature or something like that. It has been to a garage and they noted that the live data from the car was reading erratically but don't feel comfortable taking it on as a job in case it is electrical related.

Seems odd that the live data reads eratically but the gauge on the dash seems to work normally. The thermostat on the engine is a conventional one with an engine temp sensor in the housing, no electric thermostat to open close. THERMOSTAT -->

Thanks for reading and thanks in advance
I for one if you can diy would stick a new stat in especially this time of year. Not that costly and take it from there.
I for one if you can diy would stick a new stat in especially this time of year. Not that costly and take it from there.
That's what I originally wanted the garage to do on my behalf but unfortunately for me they didn't seem to keen on doing it which is fair enough.

I don't have the relevant set up such as a garage and ramps to do so, all the tools but no facilities😭, which is a real shame as it would have saved me a fair amount of money, but it is what it is for now until the garage is built. It is booked in at a Mercedes specialist to be looked at, I think their first suggestion will also be like you've mentioned, try the thermostat and take it from there. Fingers crossed it is that, and nothing else!🤞🤞🤞
It was indeed, a thermostat in the end...

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