OBC 19.7.00 - Watcha' go? doityourself

I believe the actual thermostat part number is the same for all the M54 engines. So they should have the exact same opening temp without the ECM influence since they are physically the same. The "opening" would be controlled by the actual thermostat same as any other normal thermostat.

There may be a difference in the programmed "additional" opening of the thermostat by the DME between the ECMs. This is controlled primarily by engine load and speed. I think of our thermostat as being two stage, one normal operation and the second stage with the "heating" from the application of +12 volts to the thermostat.

I might be interesting if someone has a thermostat, to do a video of it opening when +12 volts is applied.

Quote:

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Originally Posted by MrMaico

During harder running, higher revs, the DME turns on the stat heater to open it at lower temps. I see my temp drop 10 to 15 degrees F every time I run through a few gears at revs above 5000 or so.

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http://wds.spaghetticoder.org/en/zin...1214_M0KFK.htm

This characteristic map thermostat is controlled by the engine control unit dependent on a characteristic map.
This characteristic map is determined by the following factors:
Engine load
Engine speed
Vehicle speed
Intake temperature
Coolant temperature

Quote:

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Originally Posted by shanneba

I might be interesting if someone has a thermostat, to do a video of it opening when +12 volts is applied.

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I have my old one and I also have a battery sitting around. Might have to give that a try and see what happens.

Quote:

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Originally Posted by LivesNearCostco

... OBC displays 95C when moving (occasional 96C) and moves between 96-99C when stopped or in traffic... New T-stat is Wahler with 10 miles on it

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Hmm. So, I went to my favorite parts supply website and I looked up the Wahler replacement for our cars. They returned part number 11 53 7 509 227 and there was a product note "79 degrees Celcius". I wonder if my car was accidentally fitted with an incorrect unit.

Costco, can you check on what the part number was for the Wahler unit you ordered?

Also, how bad of a job was it to do the swap? I'm thinking I'll be doing mine sooner than later...

T-Stat swap is simple.

It was indeed simple; was my 3rd swap. Have to remove fan but don't have to remove the belts, though I did to try to reduce how much spilled coolant got on them. Removed plastic undertray to drain the ET, and spilled some coolant from the lower radiator hose. I partially drained the ET and upper radiator hose was fairly empty but maybe I didn't drain it enough.

I got the Wahler from ECS Tuning almost a year ago, which today calls it part #11537509227, but that's the same part # for BMW, Behr, and Wahler T-stats. ECS catalog ES#:10944. AutoZone web site says their DuraLast t-stat for our cars opens at 206F. O'reilly sells a Murray at 206F or a Beck-Arnley at 97C. Pretty sure all the Rock Auto T-stats for the E46 non-M were for 97C, 80C for the M3.

Numbers are in Celsius, once plateau is reached.

Oli77 [2005 2.5L M54 DME-MS45.1] : 96
Danewilson77 [2004 3.0L M54 DME-MS45.1] : 95
Telijah [2001 3.0L M54 DME-MS43] : 88 (suspects open T-stat)
edlvrt [2004 3.0L M54 DME-MS45.1] : 96
MrMaico [2004 3.0L M54 DME-MS45.1]: 96
Spencers [2001 2.5L M54 DME-MS43] : 90
LivesNearCostco [2003 3.0L M54 DME-MS45.1] : 91 (old T-stat)
LivesNearCostco [2003 3.0L M54 DME-MS45.1] : 95 (new T-stat)
derbo [2004 3.0L M54 DME-MS45.1] : 95
GT172I [2004 3.0L M54 DME-MS45.1] : 96
shanneba [2003 3.0L M54 DME-MS43] : 89 (running water wetter and stewart pump)
Hochspannung [2005 3.0L M54 DME-MS45.1] : 87 that's the outlier, unless these are the M car values.
Kayger12 [2005 3.0L M54 DME-MS45.1] : 95
RITmusic2k [2004 3.0L M54 DME-MS45.1] : 83 T-stat work ongoing
terraphantm [2003 3.0L M54 DME-MS45.1] : 95
Hermes: [2005 3.0L M54 DME-MS45.1] = 95
328ioc: [2005 3.0L M54 DME-MS45.1] = 95

Since changing out my thermostat, I think my gas mileage has improved between 0.5 and 1 mpg. I'm guessing it provides a bigger benefit in freeway driving when my temps formerly hovered in the 70's (Celsius).

Is there a hidden OBC function to show oil temps? I'd like to monitor those sometime.

All the codes are toward the end of the initial post. I didn't see oil temp.

http://www.zhpmafia.com/forums/showt...ve-maintenance

Hmmm... I could have sworn there is an oil temp sender plugged into the oil filter housing along with an oil pressure sender. Thought I read somewhere that some devices can read oil temp and pressure via the OBDII port.