View Full Version : M50 525I Engine Temp Gauge never gets warm

09-20-2007, 01:37 PM
I wanted to see if there were any other opinions on diagnosis for this problem. Got the car 6 months ago in warm weather and never noticed any problems. Now with temps in the 40s, heat would be nice. However, the temp gauge never leaves cold area. Heater blows cold air with cabin temp controls set to Heat and A/C switched off. Coolant level is good. My first thought would be that the thermostat is stuck in open position and if so, it would be a first for me. I understand the change of the Thermostat is an easy one. Any tricks to look out for?

09-25-2007, 10:13 PM
I'd guess the thermostat also.

On my M52TU engine it's not easy in the sense that you need to remove the fan to get to it. You should be able to do it without removing the fan shroud and radiator. Cn90 on bimmerfest.com have made a nice write-up on the replacement of the cooling system on the M52 engine. there he mentions the vent hole in the thermostat, which the ones for my car doesn't have, so he drills one in the thermostat. I didn't do that, and it works. that's the only "trick" about thermostats I've heard.

I'd strongly suggest to do a complete cooling system overhaul if you haven't replaced many of the major parts already. A failing cooling system will leave you stranded and ini worst case destroy your engine.

09-26-2007, 10:38 AM

easy repair on an m50. replace the plastic t-stat cover with an alum one while you have it off. and if the waterpump and drive belt have not been replaced recently, do them too...while you are in there....

just follow the bentley instructions..no hidden tricks needed.