Date:         Fri, 13 Dec 1996 20:57:48 -0800
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         david kao <dtkao@worldnet.att.net>
Subject:      Re: 87 Westie: Overheat light comes on with midrange temp!

Steven J. Hughes wrote:
>
> 
> It was about 15 degrees out. I was cruising along embracing my driving
> experience because the engine temp had finally reached the point where I
> was getting "warm" air out of the front heater vents. Suddenly, I notice
> the overheat warning light blinking in the engine temp indicator. The
> needle had not moved from its usual just-left-of-center point, but the
> little red LED was blinking!
> 

> I got out and checked out the engine, fearing the worst. What I found
> was: NOTHING. 
> 
> Any ideas?
> 
>

My 83 westy started out with similar symptom before it eventually developed
into a head gasket problem. What happened to yours might be that there was
air in the cooling system. At the moment the air moved to the pressure tank
it triggered the sensor which caused your temp warning light to blink. But
when you stopped to check the cooling system the air had moved on and was
not in the pressure tank to be seen any more. The big air bubble just moved
along the cooling system continuously. The bubble would be released out from
the valve at the pressure tank in a normal car. But if your engine is leaking
combustion gas into the cooling system then this problem would persist no 
matter if you bleed the system well or not.

The reason combustion gas leaked into cooling system is not because of bad
material of the head gasket. It is cuased by warped heads. As a result tmp
warning light often begins to blink in the middle of a trip and there is no
visible sign of low coolant level. In fact you will find that your reserve
tank's coolant level increased, instead of reduced which is the case of a 
normal car. The pressure of the combustion gas forces coolant back flows
into the reserve tank. In a normal car low coolant level creats a vacuum
which would suck coolant from the reserve tank into the cooling system.

I suggest that you bleed the coolant system thoroughly and see if the symptom
comes back in a few weeks. If it does then check your reserve tank to see if 
coolant level is increased instead of no change or reduced. If it indeed 
increeses then you have the famous engine problem which is common among early
vanagons. You will be entiled to receive compensations from VWoA to fix the
problem.

Good luck. Hope this is not the problem to you.

David Kao
83 westy, 84 vanagon