John,

Start with the cheap fixes first.  If the hose between the expansion
and overflow tanks is suspect replace that first - could be that the
cap is functioning correctly but can't move coolant through the bad
hose.   Could be the cap is bad.  Either of these could force coolant
out.  Both are inexpensive fixes.  I had a badly made replacement
expansion tank that would not allow the upper hose to fully seal and
when the engine was warm it looked an awful lot like the tank itself
was leaking.  If the tank is indeed leaking there will be a significant
coolant lose and the engine temp will rise quite quickly.

The coolant level sensors do go bad.  If you get a new one make sure to
get a fresh o-ring for it.

If your coolant is still fresh and the level is above the low mark and
you have a blinking light check the little nuts that hold the temp
gauge into the tach.  If these are loose you will get the annoying
blinking light.  If you aren't positive the tank is leaking, you
coolant is fresh and the level is good check this first - could solve
the problem and won't cost anything but time.

Chuck
'85 Wolfsburg Westy w/'95 Subaru EJ22

> Date:    Sun, 9 Sep 2007 12:03:12 -0700
> From:    John Runberg <jrunberg@MAC.COM>
> Subject: Date:    Sun, 9 Sep 2007 12:03:12 -0700
>
>
> We'll, now that the fuel system on my '90 is sorted, the coolant
> system wants attention.
>
> Yesterday the coolant light started blinking. Needle mid-way, rad fan
> works but wasn't even on (checked function afterwards. Works
> correctly). Engine at operating temp, but not overheated. Thin bit of
> coolant on the front lip of the expansion tank (left side of engine,
> not the overflow). Level in expansion tank looked a little low, just
> at the min line. Expansion tank looked a little high, just over the
> max line. No apparent loss of coolant previously.
>
> I know of at least two things that are bad / suspect, but would like
> opinions on other possibilities.
>
> 1) expansion tank cracked. Today, after a short drive, could see
> coolant emerging from just above the lip on the expansion tank, then
> dripping onto the header.
> 2) thin (9mm?) line coming from expansion tank to overflow tank looks
> suspect, possibly collapsed inside.
>
> Additional questions:
> - does it make sense to replace the expansion tank cap, too?
> - same deal w/ the level sensor - replace?
>
> Both these items are getting replaced, but would like to know opinions
> before I continue.
>
> Much thanks :)
>
> john
>