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Old 12-05-2012, 08:48 AM
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doru doru is offline
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Location: Calgary
Join Date: Sep 2007
Posts: 4,703
Mein Auto: 2003 530iA
I have an update. Yesterday, driving home from work: starting the engine, KTMP was 40C, and the engine warmed up to KTMP 94C very quickly, in less than 200yards. This morning, starting the engine stone cold, the KTMP rose quickly again to 60C in about 200 yards, then it stalled as if the T-stat was open. Took again about 3-4 Km to reach 94C. At stop lights, the KTMP would not even budge while idling. Once KTMP reached 94C, it would toggle between 94C-96C. Also, this behaviour is consistent with the instant mpg readings. They are out whack until the engine reaches about 70-72C, where it starts satbilizing, and once the KTMP reaches 92C, you can se a dramatical improvement in mpg.

I think I will change the T-stat this coming spring - it's too cold to work in the garage right now (unless monitoring the KTMP will show a total stoppage of that pesky T-stat, or if I get a GT1 code for the sucker).

I don't think the ECU sends wrong info to the T-stat to open it once the coolant reaches +/- 60C, but it looks like that every other time, especially if it's cold outside, or if the engine sat overnight.

These electronically controlled T-stats start getting under my skin. This is the 3d T-stat I have since I own this car.

What brand of T-stats do we have for the M54 engine anyways, aside from Behr? (the electronically controlled ones)
Should I try the "regular" competition t-stat from Zionsville (expensive)? I know I will have the T-stat code (not shown on the dash) every time I will check for codes, any other drawbacks? Any better brands?
Looking for a DIY? Parts? Check this out, it might be your ticket

Stable: e92is, e46, , e83, f25, e53 - sold, e39 RIP
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