My truck has been consuming the contents of it's overflow bottle recently...

Found no evidence underneath until today.....

The right front crossemember (under engine) is wet....

Had a quick look and coundn't pinpoint the source.

Hoping it's the waterpump or a hose....Truck has 120K on it and appears that all hoses are original.

Doesn't appear to be from head gasket or block heater....

Any clues/info is appreciated......

 

You can rent cooling system pressure testers.
They connect on rad cap opening and then you can pump up cold engine cooling system to 16psi pressure, normal hot engine pressure(when it leaks most) is 16psi.

Doing this on a cold engine allows you to pin point the leak easier since you can feel around cold engine parts.

You can also get dyes that are added to coolant, then run the engine and shut it off after it warms up, you need a UV(ultra-violet) light to see the dye on the outside of the engine.

Water pumps have a hole on the underside that will leak when the shaft seal starts to fail, that should be easy to ID on cold engine.

 

Did you find out what the problem was.

 

The coolant was coming from the block heater frost plug and where water pump bolts to block.....

A half dose of Risolene block seal.......and we're good to go....