----- Original Message -----

> Gary wrote:
> >
> > I've got an 85 passenger van and I'm getting combustion gas in the
coolant.
> > Heads were rebuilt about 6000 kms ago.  I'm thinking of pulling the
heads
> > with the engine in the van, leaving sleeves in place.  > >
> > Thanks for any ideas
> > snip
> > Gary

Bob Danalds wrote:

> Gary
> the green oring is not the problem its the gasket on top of the
> cylinder. If the engine has been overheated then the top gasket will
> leak most times it stops when the cylinders warm up and expand restoring
> the seal. I cant think of any sealants that would help prevent this. you
> may need new heads to cure this leak but give it a shot if you have more
> time than money
> head nuts can be reused torque them to 37 lbs
> Bob
> http://www.bostonengine.com

Thanks Bob for advice.

I should go one step back and explain what my symptoms are.
Engine has not been overheated since heads were rebuilt 6000 kms ago.
Yesterday was the first time I had the van on the highway and the first time
this happened.
After the engine is hot and then you stop and idle the coolant flows out of
the main plastic tank and into the expansion tank. Expansion tank overfills.
I then see bubbles in the expansion tank while the engine is running.  The
bubbles will continue after the engine is shut off.  The coolant smells like
exhaust. The main tank is now low on coolant, flashing LED blinks.
None of this happens with around town driving in moderate weather or when
the engine is warming up.
The coolant does draw back into the system from the expansion tank while the
engine cools down.

More questions:
Is it actually leaking combustion gas into the coolant if the bubbles
continues for 5 minutes after the engine is shut off?  Where else could the
bubbles be coming from?
Maybe the cooling system was not bleed properly in the first place?
Maybe one of the the heads is cracked?
Maybe defective coolant tank cap, lower than normal release pressure?

Any advice is appreciated as I was hoping to go on vacation at the end of
the week...................

Gary