Due to a number of factors I had to take a break from the list for the past year or so....but now I'm back with a continuing nuisance problem.

I need some advice...I have a long history of cooling system pressurizing problems with this van which all started after the water pump failed at about 75k.  After resealing the heads a few times I found that it was just the left head that seemed responsible.  So, I reseal the left head which solves the problem and it lasts about 10k before the cooling system starts getting pressurized again at which point I reseal the left head etc.  Most recently the pressurizing got so bad that the seal on the left head catastrophically blew and I lost coolant to the ground for the first time.  Assuming the left head was at fault again I resealed the left head, but this time it didn't fix the problem as I'm still getting pressurized coolant

Before going and trying the right head, or both, I performed the following tests.

-With a pressure gauge on the coolant tank I took a drive of about 5 miles @ 50-60mph.  When I got home the gauge (a 15psi gauge) was pegged.  This to me confirms that I have a compression leak over the barrels (or through the heads....to grandmother's house we go) and not just incomplete cooling system bleeding etc.  Am I right?
- When the engine was cold, I released any cooling system pressure and I then took an air compressor and connected it to each spark plug hole, developed 65psi air pressure and held it for about 5 minutes on each cylinder.  Watching the pressure cap gauge I was hoping I would see my coolant pressure gauge rise when I pressurized the faulty cylinder.  No luck....the pressure cap gauge never budged over 0psi on the coolant.  Why can't I duplicate the leak this way?????

My dilema is that the van is getting on in years and I don't feel like sinking a whole pile of money into it.  Should I buy rebuilt heads?  Should I pull the heads and have them tested somehow?  If my pressure test didn't show up a problem, how would a bench test?  Could I be doing something wrong that is causing this problem to recurr?  What is the proper way to test the motor to isolate where the problem is?

Thanks,

Mark

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