Hi,

Here are some simple test you can do.

First, to make sure it's really overheating and the coolant is really going
through the rad, remove front grill, REMOVE bleeder screw
http://www.benplace.com/engine/front_rad_plug_small.jpg

Put all heater to "hot", start engine and wait until it get hot (needle
center or abit above), have someone raise rpm to 2000, watch the coolant go
out of the rad bleeder screw, is it hot?, is it pooring out?

Another test, when colder, close back the bleeder in the front, remove
blue/black cap on EXP tank (the one inside the engine comp.), look carefully
around the cap, look for a crack near this one, in between the sender and
the cap? how is the level on that tank?

If your lucky! the pressure is normal, but if you have a crack, a defective
cap or even a defective sender, coolant can get out of there, level get to
low, and the light (collant level light) go ON, sadly, 50% of the time the
coolant temp goes up as well even if the engine is still at normal temp, it
should NOT but cluster, coolant relay can go bad.

The worse case, head crack, bad seal at head gasket or even cylinder crack.
Sparkplug?? wet???

Finaly, you need to do that.
http://www.benplace.com/pressure_test.htm

Ben

On Fri, 20 Jul 2007 21:08:37 -0700, John Goubeaux <john@UCSB.EDU> wrote:

>I have a situation where my 90 vanagon, after running for a few miles
>began to exhibit "cooling system problems":
>The temp needle went to the top and the red light began to flash. I
>drove a little while longer and idled downhill home.
>Coolant was leaking out of the (it looks like top of )  pressurized
>coolant reservoir and as well as being under what looks like higher
>pressure than normal. The car did not appear to be overheating. After I
>stopped the engine I could hear pressure noises (what sounded like fluid
>shifting around as the engine cooled off)
>
>Does this point definitively to a head gasket leak? If not what are the
>other possibilities?  My coolant reservoir  had signs of leakage around
>the top where the sensor fits into it prior to this and this was pointed
>out to me by a mechanic.
>
>Thanks !  -john