flightline

I'm pretty sure I need a thermostat, but I just wanted to verify here. My new-to-me '86 951 takes a couple of miles to reach the "1/3" line on the temp gauge which the manual seems to stipulate as the minimum "normal" temperature. However on the highway or cool evenings the needle begins to creep back down, ending up about 1-1.5 needle widths below that 1/3 line. How do I verify if the problem is the thermostat or the temp gauge/sender? I'll be adding an oil-temp gauge in the near future to aid in telling when it's warmed up, but how long does it typically take of gentle driving before these cars are really "in the zone"?

Thanks

Yarf

Information on gage and sensor.

http://www.clarks-garage.com/pdf-manual/elect-19.pdf

flightline

Thanks for the link. I verified that my gauge is working properly. I saw on the thermostat page there that the stat normally closes completely ~10 degrees below listed temp. Since my needle sometimes sits just below the 80 degree line (stock thermostat temp, correct?) is this considered acceptable? Assuming everything else is warmed up properly is it okay to really let it rev at that temp? My BMW's temp gauge was like a rock and I'm just trying to figure out if this is normal fluctuation or if it should really be steady a little higher up the gauge.

Also on the subject of coolant: I've got some genuine BMW coolant around, any reason I shouldn't go ahead and use this for the 951? Blue color is kind of awesome anyway. Thanks.

John_AZ

I read the BMW Coolant technical article on Pelican and the coolant should work-I guess. It is phosphate free but it has a few BMW additives that prevent "silicate drop out" ???

http://www.pelicanparts.com/bmw/tech...lant-Flush.htm

Quote:
I'm sure one question you're about to ask is "what type of coolant should I use?" BMW has issued a 1991 technical bulletin, 17 01 88(1743), which details problems with what is known as silicate gel precipitation in engines. This is the 'green goo' (yes, it actually says that in the BMW Tech bulletin - gotta love those German translators) that results as a consequence of an antifreeze over-concentration in the coolant, combined with hard water, and the phospates commonly used in many antifreezes. BMW factory antifreeze has been formulated to prevent this problem of silicate drop-out without any coolant performance loss. This antifreeze contains no nitrites and no phosphates. The part number for a one gallon container is 88-88-6-900-316, and it costs about $13.00 per gallon. Although I am always eager to find alternatives to BMW factory products, I would stick with the factory coolant for now.
end quote.

The big feature of coolant in our cars is "Phosphate Free" and most brands now are phosphate free.

Use distilled water not tap for the 2nd gallon-- 50/50 mix

Blue ---not pink BMW coolant?

John

JohnKoaWood

Didn't read the other replies, but here is the one that popped into my head when I read the title of the thread..

"To the left of your fuel gauge!"

That is all, dont get hung up on where it sits.. if you are worried, get an IR thermometer and measure the temperature of the head or the radiator...

flightline

The only BMW coolant I've ever seen is blue. I think VW coolant is pink?

Now that I've established that my gauge is working (if not with absolute certainty the sender) than what I'm worried about is not the gauge so much as the actual coolant temp. I'm trying to be kind to the car and only push it when the engine is fully warmed up, so I'm just trying to establish what temperature range I should consider a minimum for hard driving.

Thanks