I'm thinking that my thermostat is stuck open. When I bought the car in March of last year the coolant temp gauge would be steady at the 12:00 position. Over the past months I've noticed that the coolant temp never seems to the 12:00 position, even after a long drive. Here's the coolant temp after a 12 mile commute in 43 degree weather and idling in a parking space for a few minutes:
I guess the gauge itself could be faulty. Or perhaps the coolant temperature sensor. I recently replaced the SI board, which can cause gauge issues, but these symptoms exists prior to that. My gas mileage has been about ~22mpg (both before and after chip installation), so the car may be running slightly rich due to the lower coolant temp.
Thoughts on other possible causes/issues?
To replace the coolant hoses coming off the thermostat, the thermostat itself, o-ring, gasket, new housing bolts (just because), and BMW coolant it looks like it will run about $120-$130 in genuine BMW parts. I'm feeling a bit lazy so I may call a local/trusted shop to get an estimate. I've read a few tutorials (http://zoso.no-ip.org/318i-thermostat.html) and it doesn't look like a hard job. Certainly easier than replacing the "mess under the intake". I'd rather not clean up the inevitable coolant spill off my garage floor though ;) . If I a labor quote of many hundreds of dollars I'll just do it myself.
I guess the gauge itself could be faulty. Or perhaps the coolant temperature sensor. I recently replaced the SI board, which can cause gauge issues, but these symptoms exists prior to that. My gas mileage has been about ~22mpg (both before and after chip installation), so the car may be running slightly rich due to the lower coolant temp.
Thoughts on other possible causes/issues?
To replace the coolant hoses coming off the thermostat, the thermostat itself, o-ring, gasket, new housing bolts (just because), and BMW coolant it looks like it will run about $120-$130 in genuine BMW parts. I'm feeling a bit lazy so I may call a local/trusted shop to get an estimate. I've read a few tutorials (http://zoso.no-ip.org/318i-thermostat.html) and it doesn't look like a hard job. Certainly easier than replacing the "mess under the intake". I'd rather not clean up the inevitable coolant spill off my garage floor though ;) . If I a labor quote of many hundreds of dollars I'll just do it myself.
Comment