[tb30570]

My water pump failed so I replaced both it and the thermostat. I made the mistake of purchasing a VOLLIG brand rather than a Wahler or Behr. Apparently this brand isn't very good because after a couple of weeks I'm getting a list of thermostat trouble codes.

p0597 Thermostat Heater Control Circuit/Open
p0598 Thermostat Heater Control Circuit Low
p2ef5 Map thermostat, activation - Open circuit
p2ef7 Thermostat activation

I found another guy with the same issue:
http://www.bimmerfest.com/forums/sho...d.php?t=619840

I'm going to buy a better thermostat. I've found sources that say Wahler makes the OEM thermostat and other sources that say Behr does. Maybe they both did at some point.

Which do you recommend, Behr or Wahler?

[tb30570]

I found a source that said OEM was Behr then BMW changed the source to Wahler. Hard to say if the source change was due to quality issues or just a cost reduction.

[Three_thirty_I]

At least you have error codes to work with!

My 330i seems to be permanently running on the cooler high output temperature range (has three ranges, high output, normal, and eco). I replaced the temperature sensors so that the ECU was not possibly getting false readings, but no difference. No matter what the outside temperature, the engine runs at between 79 and 84 degrees Celsius! It should be running in the 90's and if in eco mode, as in driving around town, around 105! It has briefly shot up to 99 degrees, but then within a minute is back down to the low 80's! Odd! And this is not affected by different types of driving - I usually drive to conserve fuel which contradicts the engine running on high output mode, but even when belting it for a bit, still stays in this temperature range...

I have thrown lots of money at this car already with regards to the ongoing pinging issue that I have (well, the pinging like noise, put it that way), and also no error codes regarding this, so not going to simply replace the thermostat unless I know for a fact it is faulty. And since the ECU controls this and the water pump, it is further complicated...

In your case I would replace with the better brand (the OEM equivalent) and hopefully no more errors!