Re: 533i Over heating

["Jim Cash" <j.cash@xxxxxxxxxxxx>]

Damian

There are actually 2 switches (temperature switches) located on the upper
side of the rad.


One operates at a lower temperature, and starts the fan on slow speed using
a large resistor (mounted on the front of the fan).

The second switch operates when the coolant gets hotter (about 98C) and that
turns the fan on high speed - bypassing the resistor.


Since you say the fan comes on when the temp gauge gets toward the top I
suspect your resistor has gone open (they all seem to fail eventually.


Options:

- - replace the resistor.
- - interchange the leads on those 2 switches so that the lower temperature
switch turns on the high speed fan (probably not a long term solution.)


If you have A/C, then your situation is worse since the A/C system also puts
the fan on low speed whenever you turn the A/C on. It also uses that
resistor. So if you are running A/C without that resistor ten you will heat
up much more quickly.


Cheers

Jim Cash
London, Ontario, Canada

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