70's IH 674 gas has coolant leakage -Is this a common deal?

First post here so please bare with me...

We have a 70"s IH 674 gas that has a problem of leaking coolant. Site of the leak is where the water manifold and the water pump come together to act as what appears to be a water passage to bypass the thermostat. When we replaced the expired head gasket, during disassembly, we noticed clear silicone (alot of it) had been shot into and around this area to help with the rubber "grommet" that is used to butt these two pieces together. Obviously it had been leaking for the previous owner.

We used a new head gasket set which included the new "grommet" which we used. All surfaces were clean and true.

After reassembly, when checking the coolant level between uses the level would drop. Site of the leak is/was at this point where the two pieces mate.

What appears to be happening is, during use at operating temp, the surfaces expand and sealing is accomplished. However when the tractor is shut off and cools down things must contract and at that point allow the coolant to escape allowing a low level in the cooling system.

At this point in time, I am considering a couple of things. In hind sight maybe we should of applied some silicone sealant on the grommet when we put this back together. The other thing under considerstion would be block the existing passage holes and relocate and drill two new holes, insert a couple of pipe nipples and use a length of hose to complete this passage.

I"m not the worlds greatest mechanic but I would rate this design as an engineer"s dream gone bad.

Wondering if any one else has experienced this same dilema and if you did... How did you deal with it?

Thank you in advance.

Lebby

Sounds like a classic case of a bad water pump. Shouldn't need a generous dose of silicon to stop the leak. The silicon could also block other water passages.

It should be moderately easy to drain some coolant, and split the housing at that point. Take the Oring (what it is called) to a automotive store like NAPA, and find a replacement that is a little bit fatter. If that is not an option, have the surface nilled down a tiny bit (maybe .020") to allow more compression of the existing oring into the interface of the two components. Remember the Challenger Shuttle disaster was caused by a cold leaky Oring. !! Jim

I would take off what part that is there at the leak and look real close for a small crack around a bolt hole or nearby. I've seen this sort of thing on other engines where some one puts lots of silicone to stop a leak cause of a small crack at a bolt hole.

(quoted from post at 15:38:47 03/02/14) It should be moderately easy to drain some coolant, and split the housing at that point. Take the Oring (what it is called) to a automotive store like NAPA, and find a replacement that is a little bit fatter. If that is not an option, have the surface nilled down a tiny bit (maybe .020") to allow more compression of the existing oring into the interface of the two components. Remember the Challenger Shuttle disaster was caused by a cold leaky Oring. !! Jim

Click to expand...

Thanks Jim!!! Now knowing that a problem still exists will force me to be just a little more critical on the reassembly and use less assumption. Make sense? :?

Also thank you to "Stick welding" and "John B.". Close examination (eyeballing) and some silicone will be in order. :lol:

Will update on progress as it becomes available. This will probably happen once it warms up a bit. Frozen fingers and toes can take the fun out of a project real fast.

Great site you have here on YT!

Lebby