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      07-11-2016, 09:52 PM   #40
rjahl's Avatar

Drives: Z4 35is
Join Date: Jun 2011
Location: Tampa

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2012 Z4 35is  [0.00]
Originally Posted by Three_thirty_I
Originally Posted by sleepysnake View Post
Three_thirty_I, do you have an update on your situation? I read on a different forum that someone had the same problem. They replaced the thermostat and had no increase in temp until they 'reset the adaptions'.

I have the same problem. Stuck at around 75-85c. Considering this is the 'high output mode' I guess there shouldn't be a problem with pushing the engine with this coolant temperature.

That is my main worry as my fuel economy seems to be fine. Getting my Performance Exhaust tomorrow so I want to be able to push it!
Hi there,

I actually just replied to your PM a few minutes ago, but to answer your question. Sadly no, I am still struggling with these cooler than normal operating temperatures. I am curious about the resetting of adaptations, but in my case it is another annoying issue - just after I replaced the thermostat I took the car to an ECU specialist and they actually changed and programmed another ECU for my car with all adaptations reset. Made no difference. And I had a bit of a battle with these people at this ECU place arguing that there was nothing wrong with my coolant temps - they were basically saying that the "internet is wrong". I have seen too many vids of other N52 engined cars that show the correct coolant temps, and a family member has fairly recently purchased a used X3 which has an N52 2.5i and it also runs at the correct temps. In fact, it manages its temps much like my E46 - if you drive sedately, the temps are on the higher end of the scale (obviously the E46 M54 runs a bit cooler than the N52), and then if you drive a bit harder it brings the temps down a bit. On my car, it mostly stays around the 80 degree C mark, but randomly it might briefly climb to 96 degrees and then shoot back down again.
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.