Coolant Leak

[bsteinborn]

I've got an M35A2 that I picked up in CA and drove to TX back in September. The truck ran great and the temperature never went above 190 degrees. On a recent short drive I
smelled antifreeze inside the cab and then noticed the antifreeze coming in along the drivers floor and on the left front fender. Brought it home, opened the hood and it appeared
that the leak was coming from the rubber coolant hose behind the oil filters. Replaced the hose, drained the coolant that was remaining in the radiator and re-filled with new coolant.
It idled great so thought it was fixed. Took it out for a short drive and the same thing happened. Brought it back, added 3 gallons of water to fill radiator. Had planned to do
a pressure test but my tester doesn't have the correct cap size. Any thoughts on why it would dump so much coolant and yet appear fine while idling? I would expect any serious leak
to continue even during idle. Anyone know of a coolant pressure tester with the correct radiator cap size? Thanks!

 

[gimpyrobb]

It leaked in the same place?

 

[doghead]

You can easily pressurize the system by pulling out the temp sending unit(or a plug next to it) and installing a gauge and schrader valve. Your cap will act as a safety relief. Put 5 psi in and watch for your leak.

 

[bsteinborn]

It doesn't appear as though the hose I replaced was the problem. The leak must be someplace else.

 

[gimpyrobb]

Some guys have had the oil cooler cover rust through. Can you see anything wet?

 

[bsteinborn]

A shrader valve? Is this something I can pick up at NAPA? I'll do a google search too. Thanks for the tip!

 

[doghead]

http://www.spudfiles.com/spud_wiki/index.php?title=Schrader_valve

 

[bsteinborn]

Thanks, I did't know those valves had an official name. Should be easy enough.

 

[Heavysteven]

You can easily pressurize the system by pulling out the temp sending unit(or a plug next to it) and installing a gauge and schrader valve. Your cap will act as a safety relief. Put 5 psi in and watch for your leak.

You've been holding out on us....I wish i would have know this last summer. Excellent idea.

 

[drgreg]

I have seen a heavy flow of coolant, on that side due to a bad radiator cap, but 3 gallons seems like too much for that.