When Radiator Fan Doesn't Work ...

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

I just thought I'd pass along my experiences from yesterday ...

My brother-in-law calls me and says that he never hears the radiator fan run
on his '88 5kSW.  He used to hear it run at certain times, now notheing
apparent.  He came down to the house and we found that the fan did indeed
work, and so did the afterrun cooling circuit after we reconnected the temp
sender at the back of the head.  I swapped in a new temp switch in the
radiator and we ran the car ... the fan came on when the temp was at about
75% hot so I sent him on his way.  I get a call about 45 minutes later ...
now the car is overheating ... all the way up the gauge ... Well, it's now
11:00 p.m. on Sunday so the only source for a thermostat is the headless '88
5kCSQW sitting in the garage.  I hop in the car and go over to swap in the
fairly new thermostat ... I knew there was a problem when I pulled the lower
radiator hose ... the engine is still pretty warm, but almost no water came
out from the engine.  When I pulled the old thermostat out it appeared that
it had failed in a way to disable both flow to the radiator and
recirculation in the engine!  I'm thinking that it had been opening only
part way before, which made it seem that the cooling system was working ...

Moral of story, if you do happen to notice that you don't hear the rad fan
running as much as it usually does, start suspecting the thermostat ...

Steve Buchholz
San Jose, CA (USA)