It seems like a tell tale sign of a failing water pump but I guess I'm in
denial. It started leaking coolant just after the 30 K service and has
gotten gradually worse. I've got 45K on the odometer now. Overnight it drops
about one to two teaspoons of coolant on the floor. I've gotten under there
and can't see where it's coming from but it may very well be the water pump.
It's definitley the front of the motor.
My question is are there any service bulletins covering a premature water
pump failure or gasket failure for these engines (5.3L)? or should I just
bite the bullet and make the repair. Or do i just keep driving it and wait
until it starts to become a major issue?
Is it possible it's coming from the radiator cap? There is a bulletin about
coolant loss from a bad sealing surface on the radiator filler neck, it
advises polishing with 400-grit sandpaper backed with a block of wood.
Robert Hancock Saskatoon, SK, Canada
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There are no bulletins that I'm aware of for premature pump or head
gasket failure. There should be on the head gaskets, but that's another
story. The three items I've seen fail on these engines are: water pump,
water pump gaskets, and head gaskets. The head gaskets just split
along the outer edges and leak coolant, usually though...the leak
will run back along the parting line (head and block) and appear
to come from the rear. Replacing the water pump is fairly straight
forward, and probably quite expensive, as the pump comes complete
with the pulley pressed on, and new thermostat and housing. That's
a GM one, but I'm not sure if they have reman or aftermarket one's
The thermostat housing is separate (ie: it can be unbolted from the water
but the thermostat is part of the housing, so when a thermostat is changed,
have to buy the housing and t/stat as a unit. And for whatever reason, new
water pumps come complete with a new housing and t/stat.
If you just had the 35,000 mile service, maybe you got the pin hole in
the radiator hose trick performed by some good wrench ?
1991 Pontiac Bonneville LE
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