[Vwdiesel] head gasket needed?

David Cook vwdieselbunny at yahoo.com
Fri Feb 24 14:37:16 EST 2006

You can also get a fluid that will test whether or not
exhaust gasses are in the coolant.  I saw it at
Autozone the other day.  (I didn't look closely at
whether or not it would work with a diesel's exhaust,
though, you'd have to do that research.)

But, I agree, it does sound like maybe you have a
small exhaust leak getting into the coolant.

A way to test this I got from the local mechanic was
to wait until the engine was "stone cold" (EG,
overnight), then in the morning, remove the cap to
make sure there is no pressure in the system at all. 
Replace the cap and start the car.  Wait just a few
seconds (like 10ish) and remove the cap.  If pressure
releases, it is very likely coming from the exhaust.

I had an issue where the temp gauge would just go all
over the place on longer trips--presumably from the
exhaust gasses forming a bubble in the coolant-->temp
rises and the bubble burping-->temp drops.

On short trips, it was no issue so I drove on it for a
little while, but eventually a new head gasket solved
the problem.

Good Luck,


--- Roger Brown <r.c.brown at ieee.org> wrote:

> Marvin Jansen wrote:
> > My 85 1.6na is blowing antifreeze from the rad cap
> and seems to get
> > hot, over the 3/4 on the temp guage on a cold day
> after driving 30
> > minutes or more..  Maybe it's just the cap I got
> from O Reileys
> > leaking .  It's a German cap, but maybe a VW cap
> is a different
> > pressure or something. How can I check?  There is
> no apparent oil in
> > the water and no water in the oil.  The temp light
> is still coming on
> > sometimes, but after shutting off the engine while
> still rolling and
> > starting back up the light stayed off the last 20
> minutes of the trip.
> Sounds like an exhaust to cooling system leak.  My
> '81 had that problem.  A cooling system pressure
> test can rule out leaks and a bad cap and also tell
> you if the cooling system is being pressurized by
> the engine compression.
> -- 
>     Roger
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David Cook
Red '86 Cabriolet Diesel Powered
Red '90 g60 Corrado 
Brown and White '78 Westy Campmobile "Bear"
and others in various states of disrepair
Pictures here: community.webshots.com/user/superdave5599

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