Wade Shen wrote:

> Allo Mes Amis,
>
> My '85 westy seems to be running hot these days when I'm stuck in rush hour
> traffic or if I let her idle at the curb.  It seems strange that the
> radiator fan doesn't want to come on until the temp gauge has climbed up to
> about 7/8 at which point it cycles on/off at low speed.  I don't believe
> that I've ever heard it go up to high speed - though the high speed circuit
> does work when i short the aproppriate wires.
>
> I've recently replaced the thermostat and flushed the entire system, but
> neither action had any effect.  My latest suspect is the fan thermoswitch.
> Thus raising the following questions:
>
> 1) Do these things tend to go bad?
> 2) I'm guessing that these things are some sort of bimetalic switches that
> rely on heat expansion?
> 3) Is there anything particularly bad about shorting the low-speed fan
> connection semi-permanently (or at least until I can get around to getting a
> new switch)?  Particularly, I noticed that the fuel injection system uses a
> temp sensor near the water pump.  I assume this is to make the mixture
> richer when the engine is cold?
> 4) Is there any problems associated with using the the thermoswitch from the
> 86-91 models which seem to have lower temp ratings?
>
> thanks,
> wade

How do you know that it is really overheating?
Maybe the temperature gauge is off, or its sensor is bad?
Do you have any other indications?  Any boiling or steaming?  Does the engine
smell unusually hot?

Larry A.