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Re: Help!! 4kq not cooling!!

On 10/09/97 08:08:17 you wrote:

>My theories: 
>#1 Overflow bottle fails, coolant loss causes overheating.
>Is this plausible? The crack is on the front side behind the windshield
>washer bottle, it is vertical and follows an inner compartment wall. Do 
>these fail over time?? Doesn't explain lack of fan though...
>#2 Fan circuit intermittent somewhere causing overheating, increased 
>pressure cracks bottle. My incomplete (it was dark, raining and I don't
>have a Bentley yet) diagnosis reveals voltage in this circuit only with 
>key on, is this normal? In my Rabbit the fan runs independently of
>the ignition. I have voltage at socket #14 under the fan relay (#2, 
>Even at highest temp I could not get voltage to the fan connection. What
>is the correct procedure for troubleshooting this circuit esp. the relay? 
>(if you have a wiring diagram I have a fax# ;-)) I figure probability in 
>following order: fan relay, break in wiring/loose connection, 
>fan motor. Agree/disagree?
>My cynical nature forces me to consider this as well...
>#3 Head gasket?? No oil/water in wrong places, compression test before 
>purchase (me too, Phil!) was 130psi in all 5. Probably not this right...
>We're headed into the mountains this weekend and and the snow level is 
>My Rabbit does all right but I was looking for a chance to get the Q in 
>slippery stuff so any hints/suggestions would be appreciated. Replies 
>to <clangstraa@ci.everett.wa.us> will reach me more directly as I'm on 
>digest at a dial-up connection. Sorry if the line wraps are wierd, this 
>not my normal editor.

On my 4ks, I've had two problems:

1) thermostat stuck closed = split hose = steam = coolant everywhere = 
flashing light.  The light in my car refers to coolant level, not over-
temp.  In your case, it seems like you thermostat is working, but you have 
a cracked tank = coolant forced out under pressure = steam = flashing 
light.  Water has a lower boiling point at lower pressures which could be 
contributing to the steam.

2) failed radiator fan.  The bearings wore out = over load = blown fuse = 
overheat.  The fan only runs (on my car) with the ignition on.  Hot wire 
the fan and see how it sounds, or just try wiggling the fan and see if you 
can feel any play in the shaft.  Best tried cold:-)

I suspected the fan relay when the bearings failed (as it just wouldn't 
come on) and seem to remember that it's a common part, so I just swaped 
with another one in the fuse box.

Anyway, it's a atart.  The Zen in me tells me to take the path of least 
resistance, ie: try the fan/relay first as it's the easiest to check.

Either way, you should obviously replace the expansion tank.  I've seen 
them fail of their own accord.