Odd types of head gasket leaks, air in radiator, water pump seal reverse leak?

[bigalpha]

Just came across this thread.

I was curious if you ever solved your problem or figured out what it was?

 

[Ecomike]

Just came across this thread.

I was curious if you ever solved your problem or figured out what it was?

I know part, if not all of the problem was a leaky gasket between the water pump and the engine block on the suction side of the water pump. Seems it would seal up as the engine warmed up. It has been parked for other work for some time, so it may still have a head gasket issue, or other issue still. The radiator hose does get hard and the coolant system pressures up normally now (up to about 13 psi versus only 7 psi before), after replacing the water pump and water pump gasket, so that was part if not all of the problem.

 

[ceb0217]

its kind of funny that some one brought this up cuse we have 2 tow trucks (nissan truck with a hino/toyota motor) that have had the air in the rad. semptoms the dealer said its sucking air through the pump shaft seals.

 

[Ecomike]

A friend of mine that is a diesel, Nissan expert suggested the water pump seal as a possible source of the air. It looked shifted from the normal position and might have contributed as well, but I also found a leak path in the old gasket area as well. May have been both. It seems that water pump seals have been known to let air in but not coolant out.

its kind of funny that some one brought this up cuse we have 2 tow trucks (nissan truck with a hino/toyota motor) that have had the air in the rad. semptoms the dealer said its sucking air through the pump shaft seals.