At 06:46 PM 7/10/2001 +0100, Dr David McNaughton wrote:
>Am loosing a fair bit of coolant - can not see any external leaks! ....
thinking that the head gasket may be a culprit - much bubbling in water
when I remove filler cap - and - white smoke on revving engine.............
Yup, sounds like a bad head gasket, allowing combustion gases to pass into
the water jacket (bubbles in the radiator), and also allowing coolant to
pass into the cylinder when there is pressure in the cooling system (steam
out the tail pipe).
>Can anyone out there give me a good diagnostic test? ....
Fill the radiator to the top with water, leaving no air space (or at least
as little as possible). Install a presure test air pump and pressure gauge
in place of the radiator cap, apply about 10 psi pressure and observe the
pressure gauge for a while. The pressure may drop a couple of PSI in the
first minute or so as the hoses expand a bit, after which the pressure
should remain stable. If the pressure continues to drop you are losing
coolant somewhere.
If the coolant dribbles on the floor you should be able to see where it
leaking from. If the coolant goes into a cylinder, then you remove the
spark plugs and crank the engine, and the coolant may shoot out of one of
the spark plug ports. In only an extremely rare case there may be a crack
in the block that could allow coolant to leak ditectly into the oil sump
without going through a cylinder.
If you do not have a radiator pressure tester, don't want to buy one, and
can't beg borrow or steal one, then any radiator shop can do the pressure
test for you.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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