My '85 westy did this also.  An easy way to test if the blinking light and
temp. needle rise if there is an electrical problem is to start the van and
unplug the sensor at the coolant tank.  If your needle rise and light blinks,
chances are it was some kind of electrical related problem.
  However, exhaust all other possibilities that it was not a genuine low coolant
level.  Bad things happen to water boxers when the coolant gets low in the
coolant tank (not to be confused with the expansion reservoir behind the license
plate).  When the problem occurs again, pull over immediately and check the
level in the coolant tank.  Don't forget to rev. the engine to at least 2000 rpm
and hold it there for 1 minute when checking the level.  If the system is only
slightly low on coolant, you may not see it in the coolant tank until the engine
is pushing the water harder than at idle.

Regards,

Vince
'85 Westy (For sale: $7000, new engine and transmission)

__________
Date:    Fri, 5 May 2000 08:26:39 -0700
From:    Karl Wolz <wolzphoto@WORLDNET.ATT.NET>
Subject: Re: Blinking coolant light...

Slipping belt?  Look for glazing.

If your van is an '84 or earlier, a bad connection with the fluid level
sensor will cause both the light to flash and the needle to rise.  Could be
just that.  Was there any evidence you actually were running worm?

Karl Wolz