Pete2222
New Registration
- Joined
- Dec 19, 2022
- Messages
- 1
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- 0
- Your Mercedes
- C200 W205 2017 M274
The coolant temperature gauge on the dash quickly reached and stayed at 90C fine as it should when I first got the car.
I later noticed this started dropping intermittently and the orange dash light came on. Code its P0128 (coolant temp below range).
After some months I've learnt I can keep this coolant temperature completely normal (90C) provided I don't switch the A/C or cabin fan on. As soon as I switch the cabin fan on the coolant temperature massively drops. In 10 sec it goes for 90C down to 40C or even off the bottom of the display when freezing outside as it was recently.
Can anyone tell me if this is a faulty thermostat (which I've been quoted £500 for and it seems there are none in stock) or some other issue? The car seems to run fine, fuel consumption is fine. I have taken the temperature of the pipe that goes from radiator to engine a few times (using an IR thermometer). Its usually about 50-55C there if that helps.
Thanks for your help.
I later noticed this started dropping intermittently and the orange dash light came on. Code its P0128 (coolant temp below range).
After some months I've learnt I can keep this coolant temperature completely normal (90C) provided I don't switch the A/C or cabin fan on. As soon as I switch the cabin fan on the coolant temperature massively drops. In 10 sec it goes for 90C down to 40C or even off the bottom of the display when freezing outside as it was recently.
Can anyone tell me if this is a faulty thermostat (which I've been quoted £500 for and it seems there are none in stock) or some other issue? The car seems to run fine, fuel consumption is fine. I have taken the temperature of the pipe that goes from radiator to engine a few times (using an IR thermometer). Its usually about 50-55C there if that helps.
Thanks for your help.
