John, you raise an interesting point.  My '84 is doing similar belching and
I spend most of last Saturday using my 1-man bleeding procedure to get the
air out of the system, particularly the air in the two large horizontal
hoses across the front of the engine compartment.  I an beginning to suspect
the bleeder valve that runs between those two hoses.

If, indeed, the O-ring seals in the cylinders are shot, why is my engine
performance so good?  Quite frankly, when I have my van out on the
interstates, it wants to go faster than is prudent even here in Georgia.

John Lauterbach
Macon, GA
'84 7-passenger

----- Original Message -----
From: "John Rodgers" <j_rodgers@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, December 09, 2002 5:27 PM
Subject: Re: Overheating Issues

> 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
> >
>