Yes, you are certainly correct about the high cost.

The only time that the old Ford lost water was while it was being driven.
There was never any trace of water anywhere, and the engine never leaked
while it was idling.

I believe that the crack happened as a result of delayed valve repair.
However, it might have been a flaw in design.  1954 was the first year of
production of the Ford OHV V8.

Jim

Had this on my 740i V8 and it turned out that the plastic thermostat housing
would start to leak when HOT but not when cold.  Swapped it out with new
thermostat and all is well - been down to Spain twice in it and still Ok.

Not too expensive but the tell tale sign is NOT dripping water on the ground but
traces spun out from the drive belt tensioner wheel (on the V8 at least) and
disappearing on the inside of the belt NOT THE outside or the engine
compartment.

Well worth a look!

Sir Hugh of Bognor

The difference between men and boys is the price of their toys.

Intelligence is not knowing the answer but knowing where and how to find it!

Hugh Gundersen
hsg@h-gee.co.uk
Bognor Regis, W.Sussex, England, UK

The E39 has a cooling system that isn't designed for longevity.  The
radiator, water pump and thermostat all start to cause problems in the
60-90K miles range (lower end for V8's, higher for I6's).  You've replaced
the pump?  Probably look elsewhere.  That coolant is going somewhere
(although it can take a couple runs to get all the air out of the system
after a drain and refill).

The radiator plastic will develop cracks, particularly in the upper hose
fitting.  Check the thermostat and its housing (I think there's an
aftermarket aluminum housing for the M52), a preventative replacement would
be a good move if it hasn't been replaced already.

Check all hoses.  If they're original, they're of the age where leaks can
develop.

If the fan clutch has failed, it'll overheat in stop and go traffic, then
cool when moving at speed.  If you've been running the A/C on a warm day
(mid-March?) an aux fan failure can cause the temps to go up.

A pressure test on the cooling system would be a good idea.

A cracked cylinder head is a possibility if one of the overheating episodes
was significant (it doesn't take much on these cars).  Tell-tale is water
vapor in the exhaust, particularly on start up (personal experience there,
albeit with an E12).  Or it could be the head gasket (the less expensive
failure).  We'll hope you parked it sooner rather than later when the temps
began to soar.

The temp gauge on these cars doesn't really reflect actual engine
temperature.  The normal straight-up indication covers the entire spectrum
of acceptable temps (it won't move for minor variations).  When the coolant
reaches a certain level of "hotter than normal" it will finally climb into
the red.  This can be quite rapid, accompanied with the instrument panel
warning light.  When this happens, the car has to be parked ASAP (you don't
have time to drive 5 miles to the next exit) or the engine will be damaged
severely and expensively.

R / John

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