Just wanted to update the list on this head scratcher.

My sister in law's 85 4 speed with a 2.1L (that I built) started
overheating. It's always run "warm", and recently the fan switch got stuck
ON, so we had to replace the switch with a new one. The van still
overheated, and got air in the system in as little as 30 minutes. Many
listmembers e-mailed me on the doom and gloom head gasket, I was sure it
wasn't this, it's a new engine (I built it, and know what I'm doing) and
only had 15k on it. Despite "being sure", I checked and heads were sealed
tight (NO COMPRESSION LEAKS).

So I took the next step and pressurized the system to 15psi using my
leakdown tester, and found 2 small leaks. One at the hose connection at the
right front engine bay at the plastic hose running forwards, and one at the
valve for the rear heater core. I put a 2nd clamp on the hose connection,
and replaced the heater valve and the system was tight. Surely these 2
locations were where this thing was sucking air, yet not leaking coolant
(very very frustrating).

After these fixes the sucker still overheated. To make a long story short,
we replaced the radiator and it's running cool as a cucumber now! I suspect
that 20 years of "tap water" from the desert deposited enough minerals  that
the radiator heat transfer was less then optimal (another way of saying it
sucked).

It's worth noting that even with the brand new fan switch installed, and the
cooling fan would not turn on until the gauge was almost pegged full hot.
With the new radiator (and the same switch), the fan kicks on low around
mid-temp, right around the warning light, where it should! This vehicle was
sufferring multiple issues, it wasn't just one that was causing the probems.
This is normal on 20+ year old cars!

I have another vanagon (90 Carat) that has run "hot" since we got it (from
Palm Springs, CA), it is getting a new radiator this weekend, because I'm
convinced it's sufferring the same illness. It's worth noting that the
radiator replacement on the vanagon is one of the easiest radiator
replacements you can do, I suppose that's payback for the "difficult" and
"$)(*#&)#*&" jobs we have to do on them, LOL.

Since I solved this issue, I have bought an Infrared Thermometer (Laser Temp
gun) to check the in and out temps of the coolant, at the radiator, which
would have saved a lot of head scratching. If the coolant is the same temp
coming out then going in, the radiator isn't doing much!

John
Aircooled.Net Inc.