88ºC. I've measured between 86º-90ºC (~186º-190ºF) at the rad filler opening and this location very closely reflects the temp as reported by the calibrated temp sensor for my EFI system that is located next to the stock gauge sender in the coolant neck on the head. My dash temp gauge stays in a narrow range less than a needle's just above or below 3 o'clock.
This is with the stock nominal 80ºC thermostat and I would regard these direct measurements and gauge behaviour as being optimal and the way BMW intended.
Listen to Curt (except about electric fans*). The lower temp thermostats are a band-aid and can actually be bad for your motor. For some special situations they make sense but street-driven non-turbo '02s aren't those situations.
*I run an electric fan only (12" "aux" fan from a 320i) and have had no problems with inadequate cooling, even on rare 36C summer days. In fact, a properly-sized electric fan will move more air than the engine driven fan would at idle because it spins about 3x times as fast.
It may not flow as much air as the engine-driven fan would at over 3k rpm, but by then the airflow from the road speed alone should be larger than either kind of fan. A possible situation where a good electric fan might not be enough is towing something heavy up a long hill very slowly where the engine is heavily loaded and the air speed is low. I don't think that scenario happens to many 2002s.
To be fair, I know Curt was only warning about the sizing of the electric fan and was not really saying they are bad in principle.
regards,
Zenon
Always first check the engine for it settings as being RICH and then lean out so it sounds OK. Then measure the temp and confirm your settings.
1] The cheapest way of measuring the engine temperature (also the one least consistent) is to put a little fluid spit (Yes from your mouth) on the engine head.
When it stays for longer as 5 seconds the engine temp is to low. Change your carburator to a leaner setting as soon as possible.
When it stays for 3-5 seconds the engine temp is OK and around 100° Celsius.
When it evaporate in less then 3 seconds the engine temp is to hot. Change your carburator to a richer setting as soon as possible.
whats your thoughts on the above
adam