Date: Mon, 9 Dec 2002 16:27:04 -0600
Reply-To: John Rodgers <j_rodgers@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <j_rodgers@CHARTER.NET>
Subject: Re: Overheating Issues
Content-Type: text/plain; charset=us-ascii; format=flowed
A thermostat that has failed in the closed position will cause exactly
the symptoms you describe. It happened to me.
To make a fairly simple test before spending money, simply remove the
thermostat and see if it happens when running with thermostat removed.
If all functions well - other than the fact the engine is going to run
cold - then install a new thermostat. If the same problem re-occurs,
then you most likely have a seal leak around the heads, and consequently
a more onerous problem to deal with.
In my case, the thermostat would never open and caused the engine to
heat to the point that coolant expansion pressure would blow the coolant
level sensor completely out of the main reservoir. 1)The blowout
indicated a seized overflow cap. 2)With a new cap in place, the next
thing that happened was the fluid was pushed out of the system and
overflowed the overflow tank. Replacement of the thermostat cured the
problem.
My mechanic used one of those UV sensors to monitor the heat image of
the various components as the engine warmed up. He could pinpoint
exactly what was hot and what was not, and could tell when the
thermostat opened for proper circulation of the coolant.
By the way, for those that have not discovered this, there is an open
loop of plumbing that ALWAYS supplies circulating coolant to the heads,
whether the thermostat is open or not. Seems to be some sort of safety
system to keep the heads from overheating in the event of just such a
thermostat failure.
John Rodgers
88 GL Driver
DaBomb wrote:
> Dear Volks,
>
> I took my van out to go camping this weekend. About an hour and a half into
> the drive, it overheated. I pulled over and there was coolant dripping from
> what appeared to be the overflow tank. There was definitely a spray pattern
> coming from the tank. The overflow tank was full and the expansion tank was
> low.
>
> I had my vehicle towed to Blodgett's Bug Barn in San Bernardino. They
> replaced the radiator cap and the hose running from the expansion to the
> over flow tank. I sat in the shop and watched while they performed a
> pressure test and bled the system. It took over an hour. I got back out
> on the road, and not 10 miles later it happened again. I had to have the
> car towed back to the shop and leave it there.
>
> I obviously don't work on my own vehicle, but am asking the list if they've
> experienced anything like this or what they think the problem might be.
>
> For the record, this very same thing happened last August, and Chet and
> Cliff's in Sacramento replaced the identical items.
>
> It's one thing to shell out $$$ to fix the vehicle. I knew what I was
> getting into when I took on a Vanagon. But, it's quite another thing to
> shell out $$$ when the problem is not resolved. Any response, encouragement
> or advise would be greatly appreciated.
>
> Love and Rockets,
> DaBomb
> '89 Vanagon GL
>
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