Let's start a thread where everyone can summarize which parts of the cooling
system have failed when (at what age of the car and what mileage). This
would be helpful for preventive maintenance. Focus on parts other than the
head gaskets, because there has been enough discussion on them.

My 87 Syncro cooling system had the following failures:

head gasket drip                7 years         ca. 140000 kms
corrected with bars leak
still running same gaskets
at 247000 kms

hose connector 
at right rear of engine
pump to cylinder head broken    8 years         ca. 170000 kms   
replaces

expansion tank cracked          9 years         ca. 190000 kms
replaced

pinholes in pipe to left
of engine                      10 years         ca. 205000 kms
replaced

low level sensor cracked       10 years         ca. 215000 kms
replaced

plastic manifold split          10 years        ca. 220000 kms
replaced

small line to overflow tank
broken                          11 years        ca. 230000 kms
all small lines replaced

flange to 2nd cyl broken        12 years        ca. 247000 kms
replaced

note: the last incident just happened and the new flange is made of metal
(the previous one was plastic which appeared to be quite soft and brittle).
It cost an outrageous $32 Can at a VW dealer, but I would include the
replacement in preventive maintenance. It connects to a small hose linking
with the expansion/equalizing circuit around the engine.

greetings,

 
Bj�rn Ratjen

Mill Bay, B.C. 

1987 Syncro Est Alia (self camperized)
1995 Passat TD
(1982 Vanagon Diesel)
1979 VW Bus (self- camperized)