jerryz

I recently replaced my water pump, thermostat housing and thermostat. Lately the temp gauge runs high, around 100C. I have also just started using the A/C on a regular basis, it's cool but not cold. The coolant level is good, condenser fans are running, no unusual noises. Any thoughts on why it's running on the hotter side, it never got above 80C in the past 10 years.

Plutoe

I guess I would ask if the coolant sensor is good and then I would make sure that the replacement pump, if not OEM had the same pulley diameter as the OEM, ie is it running slower,circulating less fluid than the OEM!!

jerryz

I'm not sure if the coolant sensor is working properly, how would I know?
This higher temp has only recently been a problem. I replaced the water pump over a month ago. i compared water pumps and the old and new were identical.

desired_speeds

Coolant flush and a thermostat may take care of it.

edwinwalke

Was the temp OK after you installed the thermostat and WP? If so, my guess is you got a bad thermostat. Even if it is getting to 100C that should not be a problem especially if the ambient temp is high.

jerryz

I'll try another t-stat, they have been known to be bad.

CKonstantin

I'm not sure if you should be worried, just double check your temperature with Climate Control unit, my gauge also seems to be hovering around 100 mark after switching, although the temperature according to the ACC is ~95*C. Also Mercedes describes normal working range as 95-116*C. It is not that it runs high now, but you were probably running too cold before due to a bad thermostat.