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Injector Cooling Fan & Aux. Coolant Pump Update
Well, a long time ago I promised that when I started troubleshooting the
injector cooling fan and after-run coolant pump on my '86 5KCSTQ I would post
results to the list. As of this weekend, here's the scoop:
The thermoswitch that controls the injector cooling fan apparently is bad.
This is the switch on the heat shield just about four inches in front of the
wastegate (towards the front of the car). This switch is a grounding switch
- it connects the fan to ground, so it only has one wire. Removing the wire
and grounding it against the body of the switch causes the fan to work on my
car, so I will be replacing the switch. Glad the fan motor isn't blown.
Helps to troubleshoot this with a cool engine. One down, one to go.
The after-run coolant pump was a little more problematic. I pulled the
connector off the pump and connected a multimeter to it. With the key off,
the connector reads 11 volts, constantly, engine cold or warm. Left it
attached to see if the relay disconnected it eventually...15 minutes later
(key off), this doesn't happen. Reconnecting it to the motor, nothing
happens either, so I suspect the motor is toast.
Remove the connector again, switch on the key with the multimeter attached,
voltage drops to 0 at the connector. This is probably as it should be. I
think the relay that controls the pump went bad, (or else the thermoswitch
that controls the relay that controls the pump is bad) letting it run
constantly and burning it out.
Now the problem is finding the relay. Looking in the Bentley, it says the
relay should be in Auxiliary Relay Panel I, underneath the steering column,
right next to the interior-light delay control unit. Removed the parcel
shelf and lower covers, located the light control unit (felt the click when
interior lights go on/off) however, the next block contains no relay,
instead it has a wire connector block with two connectors attached. In fact,
there are no other relays in the block, just connectors.
So, the control relay must reside elsewhere. I suspect the passenger's side
dashboard, behind the A/C programmer (Where Aux relay panel II is supposed
to be according to the Bentley).
Pay heed to the Bentley when it says things like:
"Actual locations of relays may vary according to model year and individual
Are any two of these cars alike????
Also: I picked up the trick S6 radiator cooling fan from a nearby dealer.
It looks like it MEANS BUSINESS. It has about 10 scythe-shaped blades and
resembles a turbine. I'll bet it flows a ton of air. The parts guy looked
at it and said: "If you hadn't picked it up today this was going on my car."
$40 bucks. Now I just have to get the $*!^$% fan motor out so I can put it
on. Then I can get the other cooling systems working and I will fear the
heat no more! I've been reluctant to drive the car in the 95+ degree weather
we've been having without these components working properly...the underhood
temperatures once you park the car are astounding. The injector cooling fan
is there to blow air around under the hood, too.
Finally, while I was underneath the car I noticed that the little horn
attached to the front of the airbox that is supposed to help the car breathe
cool air (it curves away from the turbocharger) was melted straight through
by the turbo's heat. Oh well. I removed it. In about a week or so (they
say), TAP will have the K&N Cone filter conversion available to replace the
stock airbox, so I'm not too worried about it. No more filter changing
hassles and they promise 12 extra horsepower. We'll see. Also, there is a
lot of gunk trapped between the A/C and the engine radiator that I will be
brushing/flushing out before I button everything back up. Take a look in
there on your car and you might find a bird's nest or Jimmy Hoffa or