Jack, please note that when coolant sensor thinks there is low coolant, the
temp gauge goes to H even though the engine may be at or even below normal
operating temperature.

John
Macon, GA
'84 7-passenger

----- Original Message -----
From: "Jack Keegan" <keegan@CECS.PDX.EDU>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, June 07, 2004 6:42 PM
Subject: Overheating problem

> I have an 85 GL with the 2.1L engine and a few overheating questions for
> any of the wise and experienced folks on this list.
>
> Background: I took it in for a fuel leak and the mechanic found a
> coolant leak, and it is the all-too-common head gasket, but it's not too
> serious at this point, and more importantly, I'm broke, so it's going to
> have to wait.  He also found that there was no coolant overflow tank
> behind the license plate, and that the cap on the main tank was the
> wrong one, so he installed an overflow with the right cap.
>
> After that, the temperature light started flashing now and again.  The
> temp gauge would immediate go to max as well, even if the van had been
> sitting for an hour or so.  If it started flashing while driving,
> turning the heater on would immediately solve the problem, and it would
> stop flashing and drop back down.
>
> Well, the last time I drove it, (it's not a daily driver, so a couple of
> weeks had passed) the light started flashing, and the heater didn't help
> right away, so I stopped.  I looked at the engine, and the main coolant
> tank was really low, but the overflow was overfull.  When the engine
> cooled down, I opened the main tank to add coolant, and as soon as it
> was depressurized, it filled up, not all the way, but mostly. So I added
> coolant and went home without problems.  When I looked closely, I found
> a tiny little crack in the main reservoir.
>
> After it cools to RT, the main tank is basically full, and there is way
> too much coolant in the overflow behind the license plate.
>
> Could the crack in the main reservoir not allow the coolant in the
> overflow to be sucked back into the main tank? It seems like it is only
> going one way-into the overflow. Would replacing the main reservoir or
> sealing the crack help the problem?  If I decided to try sealing it,
> would I want to drain the overflow tank some before using, because it is
> way above the max line at this point? What is the best way to do that?
>
> Also, the coolant leak was really minor before the overflow tank was
> added, and we never had overheating problems. It seems to have gotten
> worse, a couple of drops of coolant on the pavement overnight vs a 2-3
> diameter spot. Would adding the overflow make the head gasket leak
> worse?  It also doesn't seem to leak all the time.  I'll get a little
> spot every 3rd or 4th time I drive it.
>
> Any advice on this is appreciated.
>
> jk