I just put in a new, genuine BMW 88 degree Celsius thermostat in my S52 today. Install went great.
My old faulty thermostat (via OBD2) was showing 83-87 degrees Celsius as my engine temp at the head, on the open freeway, in the cold. It is now showing 90 degrees Celsius after the new part change out under the same conditions.
I am assuming, and this would make sense, that this 2 degrees Celsius difference (from the 88 degree t-stat listing) is the heat picked up from the coolant over the engine before it reaches the temp sensor in the head and this is a normal readout. Or, is this new BMW thermostat slightly off out of the box?
The only reason for the confusion, is that before I had problems with my old t-stat, the OBD2 temp readout sat right at 88 degrees Celsius in the cold driving on the freeway, but possibly the old t-stat was always off/slightly low (and was really opening at 86 degrees Celsius or so).
I apologize if my readings are normal. Thank you so much for any insight!
Cheers,
KJ
Thermostats are not perfect. A degree or two of variation is normal. Then understand that the thermostat regulates the temp of the coolant entering the engine, the sensor on the S52 reads the coolant exiting the engine. So the gauge will read nominal 88 plus what ever hear is picked up traveling through its course, very load dependent. I'd call what you have now as normal.
Excellent, thank you Randy! I figured so, but, just wanted to make sure. I really appreciate the quick response.
Cheers,
KJ
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