Can over cooling be caused by air?

[Javier]

tstat is OK and tstat housing cover is OK, if cold, tstat would simply close rising temp.

It should be a metering error, I mean, sender unit (you change it already), wiring defects, or even gauge miss-adjustment.

There is an easy check, just unbolt sending unit (or get the old one that seems to be OK as problem continues), keep it plugged in the connector, look for a camping stove (or other means of getting boiling water), pan, water, a cooking thermometer 0-100 degrees C, turn key to energize gauges, and check your gauge readings at various temperatures from 0 to 100. (if no thermometer, at least you know boiling is at 100, and its pretty close to 1/2 (center gauge is about 84, 100 is about one needle past center).

This is what I would do myself, not having handy the sophistication of an infra red gun. Also this will confirm your metering system is/is not OK.

This link should help.

http://www.bmwe34.net/e34main/troubl...e_overheat.jpg

Javier

No, stays cold all the time.... if it was getting to 12 o'clock it would be perfect.... it's pretty much rock solid on the 1/4 way mark.