E46Fanatics - View Single Post - High coolant temp. Help please (sitting on the side of the road content)
View Single Post
Old 12-17-2012, 06:39 AM   #37
Registered User
Join Date: Aug 2008
Location: Sydney
Posts: 3,372
My Ride: 332Ci
Originally Posted by Brissyjohn View Post
I'm not sure I agree with the thermostat theory. Once the car has driven about 1 or 2 km in current Brisbane conditions, the thermostat will/should be open. Thermostats (engine) rarely just fail and then close mid drive. It's more a case of them never opening fully or jamming open or closed. If jammed closed from the start, you'd be overheating everywhere. Of course, if that pesky auto transmission thermostat has failed then all bets are off.

It wouldn't hurt (except your wallet) to replace it. I'm fairly paranoid about coolant temps, but I'd be closely monitoring it for the time being to see what happens - especially if you have a monitoring system better than just the dash temp gauge.
I totally agree with you but nothing else is logical. For the coolant temp to rise substantially like that whilst traveling at 60+ks an hour it can really only mean that the engine isn't getting coolant circulating though it. Be it from the water pump not being driven, thermostat failing to open or the coolant leaking at a high speed.

Considering I've got full coolant and the water pump hasn't shown signs of failure / wouldn't generally stop working intermittently the thermostat seems to be the next logical step for me.

Having said this. I've only got what I've read in the last 48 hours to base my opinion on. Considering the thermostat was $50 and some new coolant is also cheap I'm going to start there then if I still have problems I guess it's likely to be the pump itself.

DeclanM3 is offline   Reply With Quote