Re: 88 5ktq Rad Fan Stage 1

[Eric Maxon <emaxon@megsinet.net>]

Mike Hopton wrote:

>      The radiator fan on my '88 5ktq runs all the time when the
> climate
>      control is switched on (independent of the setting e.g. Bi,
> Screen,
>      Auto etc). This happens even when the engine is cold, doesn't
> seem
>      right to make sense to me, is it supposed to do this?
>
>      If I turn the climate control off, then the radiator fan switches
> off
>      (engine cold). Does the temp switch at bottom left hand side of
> the
>      rad control the stage 1 speed, if not which of the myriad of
> sensors
>      does? It's definitely stage 1 'cause when I pull the relay the
> fan
>      stops.
>
>      Thanks and regards, Mike

The fan will always run at stage 1 speed (or faster if the 3 prong
switch in the radiator has turned on stage 2 or 3,) whenever the AC
compressor is switched on, even when the car is "cold."  The AC
compressor operates in all climate control settings except OFF and
ECON.  Since the AC compressor will not turn on when the outside air
temp is below 32degF, neither will the fan.

If you're having trouble getting the car up to normal operating temp in
cold weather, then check that the thermostat is closing all the way.
The thermostat housing is under the hydraulic pump, on the left side of
the block.  Have a coolant drain pan, new o-ring, new thermostat, and
1/4" drive 10mm ratchet handy when you remove it, and don't even think
of removing it unless the car is ice cold.  If you can't dislodge the
thermostat with your fingers, use a screwdriver to pry it out *only at
its edges*-- *not in its arch* since this will bend and ruin the
thermostat.  Once you've removed the thermostat, clean it with cold
water (to make sure it's closed as far as it will go,) and fill the area
under the "arch" with water-- none should drip past the plate.  If the
plate doesn't close completely, coolant will always flow through the
radiator, and the car will take forever to reach operating temp if it
does so at all.  The o-ring goes over the thermostat, not vice versa.
Clean the thermostat housing thoroughly. Coat the two bolts that hold
the housing in place with anti-seize lubricant.  After you've refilled
the cooling system, let the car warm up completely and *top off the
expansion tank*   Squeezing the top radiator hose as you're filling the
expansion tank helps burp trapped air from the system and lets you know
when it's almost filled-- if it feels like a sausage, it's filled with
coolant and you're almost done.

Don't pull the stage one relay to make the car warm up faster-- this
will disable the "after run" function of the fan, which is important for
cooling off your smokin' turbo once you've shut the car off.

Eric Maxon, "The Manicured Mechanic"
Chicago, IL
(86 5000cs, 84 4000s, 82 4000s, 84 GTI, 80 Scirocco-- okay, I'm an
addict & a pack rat.)