>Currently, I am driving this van without a thermostat.

I've heard some rumors, although unconfirmed, that driving without a
thermostat has undesirable effect on cooling system flow/volume/pressure
(either or all).

What I do know for a fact that the longer an engine takes to warm up, the
worse it is for the overall life of the engine.  A cold engine has excessive
clearances which may send raw gas past the rings washing oil from cylinder
walls, and in worst case scenarios, diluting the oil in the crankcase
causing low oil pressure.  Now, I do know our fuel injection systems have an
enrichment valve which is not dependet on the engine temperature, so the
problem will not be as profound.

One word about the 80C thermostats.  They will open earlier, but will not
increase your cooling systems total capacity to remove heat from the engine.
Whatever thermostat you choose, put one in.  It sounds like your previous
thermostat failed to open fully.

Chris.
'85 Westy.