Morning

last couple of days i have noticed that my 92 745t is taking longer to to warm up than it use to at operating temp. could this be that my t stat is going bad?

thanks

If that is thermostat indeed:

they actually come either in 92C or 87C temperature rating. Some time ago, I replaced t-stat at my 745 Turbo, but forgot was it 92C or 87C. I believe it was 87C. I got one from the dealer for ~$20. An aftermarket would be ~$10. If buying make sure the new rubber O-ring comes with it.

When changing t-stat, it is a good time to flush the cooling lines and may be even change some hoses to radiator and expansion tank.

Good luck,
Wolandir

i should also add that my heater only works in the #5 or high position which may also be why my t stat is on the outs.


when it rains...
:(

Non-turbo models use a 92C stat. It does indeed sound like yours has failed. Replacement can be quick and easy, but if you are in doubt about coolant condition or it's been 2+ years since the last change, now is the time to do a flush 'n refill.

Your owners book will tell you to start driving (gently at first) as soon as the engine is running smoothly - no need for a warmup at idle.

If the blower fan only works on one position of the switch, then the switch or resistor is the problem - nothing to do with your engine 'stat.


--
Bob (son's 81-244GL B21F/M46, dtr's 83-244DL B23F/M46, my 94-944 B230FD and 89 745 (LT-1 V8); hobbycar 77 MGB, and a few old motorcycles)

Try the thermostat. It's cheap and a pretty easy fix. Replease the coolant pressure first and retighten the cap. You don't loose much coolant and you really don't need to even take the hose off the gooseneck.

That's usually your best bet although it will take longer as the air temps drop. It's been my experience that if the heat disappears after idleing for, say, 10 -15 min then the thermostat has probably come apart and can't close.

It is cold here in Chicago but not as cold it is normally..when its frigid cold i know it will take my car longer to warm up but it was not that cold this morning and it took my car something like 30-45 min.to get to normal and that was while i was driving this morning.usually it will take a shorter time to warm to normal after driving. when i first get into my car i do not immediately start driving. i would wait at least five minutes before moving.

Are you using a 5W-something oil? 5W-30? In synthetic, a 0W-30?

The lower winter viscosity will give a quicker pump-up. Then I would start and drive away, for a quicker warm-up.

Do replace the thermostat with a 92C (if in spec for the 740s). They are inexpensive and the labor to replace is about the same as to just check out. If the old one is good, you have a good spare.

Good Luck,

Bob

:>)