Followup post: recap
It has been a month since I changed the Oil Tstat. Not a fun item to reach in and change and I am not sure it made a huge difference.
However about a week after changing the Oil Tstat I also changed:
*main water tstat and housing which comes with new heater element
*lower radiator fan sensor switch
*upper water sensor (in water pump housing)
*automatic transmission thermostat (on back of radiator above connections for oil cooler)
*upper and lower radiator pipes
Something in this second phase has made a difference. The main difference I seen now is much quicker times to have the oil temp needle move off of stone code (120) over to 2nd mark. Prior it take 30-60mins of driving to move off to the 1st mark. Now it takes 10-15 minutes of normal driving to hit the 1st mark and now I have even seen it hit 2nd mark (yes 210!!). There has been some variablity in outside temps but all of these timings are from COLD overnight start (35 degree garage) and driving in 10-30f air temps.
Also I notice the transmission is MUCH quicker to warm up and shift smoothly. Prior it would slightly hang in 1st gear and gently kick a bit for first 15 minutes. Now it rarely does that at all. What I see is that the trans fluid might be a tad low (cold = lower level) but regardless the trans is much happier now.
Last observation is this. The water coolant temp is now fluctuating between holding steady 93-95 or at 103-105 when once warmed all of the way up. Prior to any new parts it would ONLY settle around 93-95 (I was never seeing anything over 100 and rarely would see 100).
Now if I am driving gently (grandma gas saving style) or idling a bunch it will settle around 103-105. However if I am driving with some moderate spirit the coolant temp settles in range of 93-95. Roughly a minute after adjusting styles the temp range adjusts to follow.
Also I am wondering if the temp ranges seem correct. Do understand the computer is suppose to use the tstat heating element to false tstat into opening early when under spirited driving conditions? Would seem to make sense.
Leaves me wondering. Was my coolant temp running too low before or at least lower than BMW set it for due to partly open water tstat?
Regardless the X is heating up the oil faster and the overall coolant temp is running hotter. Not sure if I like that part
Although in -10F it still does not hit 210 (matches post from srmmmm, thx!)
Questions / Thoughts ?