> I fear that boiling antifreeze is a sign of more than hot oil.  Where does
> the coolant temperature gauge needle sit during all of this?

Dead center on the LED, rising a needle's width above until the
radiator fan kicks on, which drops it back down. It's been almost
ridiculously reliable in this regard.

>  Just a WAG but
> I thing you might have a failing water pump allowing hotspots to form in the
> engine.

This is a possibility, but if so, it's been failing in exactly the
same way without getting worse for 4 years and 20K miles. I get enough
heat out of the heater core to turn the inside into a sauna, so I'm
definitely seeing good water flow. It's not an exhaust leak, since I
only see bubbles after I stop the engine, and the bubbles vanish as
soon as the his the pressure tank and condense.

> Possibly the radiator is on it's way out also.

Well, the radiator was changed when I changed the engine, and I have
good, solidly normal coolant temperatures. I suppose I COULD change
the water pump on the off chance that's the issue, but it doesn't seem
like that the problem. I'm just seeing alot of heat from the bottom
end and the top end cooling system just can't keep up with it
effectively. It probably doesn't help that I'm hauling heavy stuff up
hills in the heat with an automatic transmission--- that's yet another
pretty good heat generator there. The oil cooler has so far worked
wonderfully, until the thermostat stuck open.

--
John Bange
'90 Vanagon - "Lastwagen"
'90 Vanagon GL - "Wiesel"