Mixing Sierra (Propylene Glycol) with any other coolant (Ethylene Glycol) is
a recipe for a mess. The gritty stuff in the coolant system can be from a
number of sources with a common one being poor quality water. The worse
cooling systems are the ones with long term slow leaks. As coolant leaks out
the minerals and debris are left behind. As it is replaced more is added
along with fresh oxygen to get the corrosion process going. It is also
possible the stuff you found is some type of stop leak.

As for the engine being repairable it most likely is. Why did the gaskets
fail? The cause will tell a lot.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
David White
Sent: Saturday, February 12, 2011 11:11 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Coolant sludge?

Can anyone describe what coolant sludge would look like? I had both
head gaskets fail at the same time and I've pulled the engine and
removed the heads. I notice that there about a quarter inch of "sand"
in the bottom of the coolant reservoir. Is this the famed sludge? This
84 1.9L had a mixture of the green Sierra and the Zerex G-05 phosphate
free stuff, probably about 50/50. The heads look like they have been
leaking for awhile, not alot of pitting under the gaskets though, just
gasket failure. Should this engine now be a boat anchor or can it be
saved?

David in Idaho