Re: 405 Mi16/1989 temperature sending unit problems
Michael A Savage (msavage@juno.com)
Mon, 15 Sep 1997 09:35:25 EDT
On Sun, 14 Sep 1997 17:29:52 -0400 Robert K Cullemore <robertkc@storm.ca>
writes:
>Hello all,
>
>I was wondering if anyone has any ideas on the following...
>
>When I have the temperature sending unit hooked up (into the bottom of
>the thermostat) the cooling fans do not come on at the specified 90
>degrees celcius. The general diagnosis for this is to replace the
sending
>unit. Well, my collection of Mi16 engine's and associated parts means I
have
>two other sending units and neither of them hooked up activate the fans
>either. The fans DO work because when the sending unit is disconnected,
the
>fans come on (which is how I have things at the moment)
>
>Of course, with this setup, there is no A/C and the fans are running
>all the time.
>
>Any ideas on this topic would be much appreciated. Apart from that,
>all is well with my Mi16, after 4 months in hibernation this summer.
>
This sounds like a classic case of coolant from a leaky thermostat
housing fouling the plug attached to the temp sender. You may have
already replaced the t-stat gaskets(If you have not, than do it now), but
I bet the pins in your plug are still fouled with coolant (wet or
dried)...which would cause the symptoms you describe.
I bought replacement pins and a new plug (the latter was unnecessary)
from the dealer and that cured my problem. It is standard bosch plug, so
a good auto parts shop should be able to find replacement pins.
If you can remove the plug and the fans come on high, then it rules out a
problem with your ECU, fan relay, or fan motors.
Mike Savage
1989 405 Mi16, 111k miles
Boston, MA