88° Thermo on M62TU: What Should KTMP Values Look Like?

[peter540]

'03 540i. Running the 88° thermo with temp tables remapped by DUDMD to eliminate the P0128 low-coolant-temp error code.

Question. I'm in Atlanta, and ambient outside temps have been getting into the low 90s. I drive in stop-and-go traffic, running AC. I'm seeing KTMPs anywhere ranging from the mid 90s to up to around 102°. Is that an acceptable range with this thermo?

(Yes, I've searched this forum to seek this info. No clear answer that I could find out there.)

Thanks for your help...

--Peter

[Flounderasu]

KTMP is 93 pre-summer ambient temps.

Now that it's 100+, 93-95 is where she normally sits with the AC running. It will get up to 99-100 sitting in traffic/drive-thru. I"ve seen 102 here and there but that's about the time the aux fan goes into takeoff mode.

[dannyzabolotny]

That's not bad at all. I was always under the impression that an 88º thermostat is too cool for the M62tu, but if the average temps are still in the 90º+ range then that's still pretty good in terms of efficiency and whatnot.

[peter540]

Thanks, guys. Good to know the values I'm seeing are normal...

--P

[Dave Sal]

I have an 88 degree thermostat in my lowly 528 and the temps average between 87-90 during the cooler months and between 90-93 during summer. So far its never reached 94 to my knowledge.

Correction: today it was about 97 degrees here and the KTMP got up to 96 for the first time.

[BMW540san]

In my experience (as some of you know I've sold bunch of 88 C thermostats and got feedbacks from customers), it should be running most of the time at 88 C - 94 C. I think you ought to check operation of your OEM electric fan and your Spal electric fan plus make sure your radiator fins are not dirty / bent.

[peter540]

Okay. Yes, my SPAL fan isn't coming in at its low speed, which is a separate issue. Think I have the fix for that.

--P