We just went through this, only our light blinked all the time.  I thought
the same as you that there must be gas pressure somewhere because the
expansion tank was full.  But we just replaced the leaking expansion tank
and seal ($30) and brought the coolant back to 50/50 and we're seemingly
back to normal.  At the very least, you'll stop the leak and you won't have
to keep adding water and bleeding the system!

Bill

PS:  You should replace the sender at the same time

----- Original Message -----
From: Renouard, Robert <Robert.Renouard@METROKC.GOV>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 29, 1999 2:45 PM
Subject: Re: Head leaks & Witches Brews.

> I've got the famous blinking red light syndrome and suspect gasses are
> getting into the cooling system because the fill tank level is always
higher
> than the cap.  A mechanic friend told me Silver Seal was definitely better
> than Bars Leak because it gums up the systems less.  I have decided to
drive
> it untill it dies because the motor has 180K miles and will replace with a
> new long block.  Right now I am gettting about 200 miles before the light
> comes on but interestingly, once the light comes on, I can turn-off the
> motor, restart it and the light turns off and the temperature gauge
slightly
> drops.  This gets me an additional 100 miles before I have to add about a
> quart of coolant.  A few Questions:
>
> 1.  Why does cutting the engine and immediatly restarting drop the
> temperature?
>
> 2. How long can I expect to survive like this?
>
> 3.  Even though I can add coolant and bleed the system in less than 10
> minutes now, I am unsure of the sequence of steps.  Bently does not say
when
> the engine compartment bleeder valve should be closed.  For me it goes
like
> this:
>
> A. Park uphill @ 5 degrees (not difficult in Seattle)
> B. Remove grill and open radiater bleeder valve until air escapes
> C. Open rear valve
> D. Pull hose and open top tank (licsence tank would spill if opened)
> E. Hold throtle w/ wire tie at 2000RPM
> F. Fill top tank untill leaking from radiater bleeder
> G. Close radiater bleeder and close top tank in back
> H. Release throtle
> I.  Tighten engine compartment bleeder.
>
> Should the back bleeder be close first, before the top tank cap, or last?
>
> Finaly, the licsence tank shows leakage along the top seam.  Could  a
leaky
> tank be my problem, or is that just an other symptom of gasses in the
> system?
>
>
>
> > ----------
> > From:         Per Lindgren[SMTP:lindgre@ONLINE.NO]
> > Reply To:     Per Lindgren
> > Sent:         Wednesday, September 29, 1999 12:03 PM
> > To:   vanagon@GERRY.VANAGON.COM
> > Subject:      Re: Head leaks & a GM mechanics suggestion.
> >
> > David Hayward wrote:
> >
> > > The product is simply a GM COOLING SYSTEM SEAL TABS (part no.
1051687).
> > The
> > > make up (as shown on the back of the pkg) states it is made from
GINGER,
> > > ALMOND SHELL & BORIC ACID.
> > >
> > > Do any of you engine experts know anything of this product or have any
> > > experience with it ?
> >
> > I've heard an ancient tip from generations ago, to drop some cinnamon
> > powder
> > into the coolant to stop seeping coolant from small holes in radiators.
> > I've
> > tried it once, in a friends Peugeot, it worked for a couple weeks.
> >
> > PerL
> > 87 Syncro 112i
> >
>