Thought a few items which may helpful to the diagnosis.

Some questioned source of the leak - it is the coolant level sensor has a crack in it that you can see, once you remove the O-Ring - old one failed the same way.

Last trip with the van was 2 1/2 hours with no problems, but it did run a bit hotter than I thought it should in mild traffic, getting almost 3/4 the way on the gauge.  Normally, the needle sits just to the right of the LED.  Just fixed the gauge, so I don;t have a normal base line for this engine.

I recently replaced a hose and bled the system prior to the 5hr trip (up and back).

This morning, I had no coolant in the overflow tank, I filled it up this morning before taking the van to work, but the expansion tank was almost filled - but with air bubble at the top and it usually is in this van.

I had replaced the pressure tank cap last time I did the sensor, but the replacement cap is not a VW one, and inside the cap it looks slightly different from the VW-AUDI cap that was on the van when I bought it.   On the fence whether to buy a new dealer cap.

John

-------------- Original message --------------
From: "Jim Felder" <jim.felder@gmail.com>

> That's what it was on my vanagon. Blown head gasket or cracked head.
> Check it out now. Don't wait for the worst to happen like I did.
>
> Jim
>
> On Tue, Aug 26, 2008 at 9:54 AM, John Reynolds wrote:
> > I had a coolant level sensor develop a split late last year, I replaced it and
> now with less than 1,000 miles since that time, the new sensor has split as
> well. I was careful tightening it.
> >
> > Could there be some reason, like too much pressure in the system that could
> create this problem?
> >
> > This is an 86, 2.1 Vanagon
> >
> > John Reynolds
> > LiMBO
> >