1988 740 turbo cooling fan temp sensor/temp gauge/timing bel

vcolper · Post by **vcolper** » 29 Oct 2006, 22:50

I have a bad coolant temperature sensor (for the cooling fan) thats mounted on the radiator.
Is that part available?
Does it unscrew from the radiator?
I dont want to break anything and the Haynes manual doesnt say much about it.
Also the temp gauge doesnt work. I've disconnected the wires to the sensor...jumped them, opened them....no response on the gauge?
any suggestions.
My car is a 88 740 turbo. How far should the Turbo gauge needle go under full throttle? Mine just bearly goes past 1:00 o'clock. This car is really lacking power. I believe it is the timing.
Next weekend I plan on replacing the timing belt. Any hints or tips?

Thanks,

Vic

Post by **billofdurham** » 30 Oct 2006, 12:15

The radiator fan sensor is available and does just screw out. Drain the coolant to just below the level of the sensor, disconnect the leads and unscrew it.

I would suspect that the temp gauge sensor is faulty. It is a common problem, more common than a gauge going bad.

How far should the Turbo gauge needle go under full throttle?

How long is a piece of string? No car gauge is 100% accurate and not all will give the same reading. I would have thought that it would go higher under full throttle, but if the turbo is working do you need a gauge to tell you?

The Haynes manual gives a good guide to replacing the timing belt. If you have Haynes you are good to go. Take your time and double check everything as you do it.

Bill.