View Single Post
      07-11-2016, 10:11 PM   #41
Lieutenant Colonel
Three_thirty_I's Avatar
South Africa

Drives: '05 E90 330i Manual
Join Date: Aug 2010
Location: Cape Town, South Africa

iTrader: (0)

Garage List
Originally Posted by rjahl View Post
Try logging the temps, thermostat position and water pump speed with testo or simply watching them with INPA. If you live in a cooler climate you will need to drive the car while connected to a laptop.

Armed with actual data you should be able to locate your problem.

I think you will find that the thermostat just opens at 80c and the water pump speed is used to regulate block temp while the fan speed Is used to regulate the inlet coolant temperature.

Climate control settings change these values somewhat. Try turning your AC or heater off and watch your water temps rise as the water pump will run slower.
I am going to still get my diagnostics PC sorted out, and want to also get my notebook sorted out so that I can take live data readings while on the road. So I gather testo will show what the thermostat and water pump is doing, so one can then determine if the thermostat is not regulating the temp or the pump is not correctly regulating the coolant flow? I can only think that while the thermostat typically regulates the temperature, it's also the water pump that plays a part, so just like you get a thermostat that is mechanically stuck open, makes me wonder if you don't have a water pump that doesn't regulate properly and moves too much coolant when it's suppose to either be a lot slower or not at all.

I have actually tried playing around with the climate control settings while monitoring the coolant temp, and didn't really make any difference. We have fairly warm summers, but winter at the moment and while it does get close to the 0 C mark over here, that's only on the coldest nights, usually above 10 C during the coldest days, so I would classify as anything other than moderate temperatures in general. And what I have observed is regardless of weather, so at least whatever it's doing, it is able to "maintain" what it thinks is the correct temperatures. Just need to figure out why it is these lower temps rather than the correct temperature ranges.
BMW E90 330i (M) '05 (His) | (Hers) BMW E46 320i f/l (M) '03