There has been problems with other w/c VWs in the coolant light
circuitry - My 83 Quantum takes about 5 miles in the morning before
the circuit decides everythings okay. Service bulletins about this
exist - applicability to Vanagons ???????

My diesel Vanagon light had a phase where after 30 seconds of engine running
the light would flash, temp gauge fine though. I think the level must
have been the trigger although i recall checking and finding it was
up to max in the relevant tank. Great mysteries of the universe ????