Concurrences

(2) An oil and filter change is perscribed, by almost every manufacturer of motor vehicles world wide, as routine preventative practice any time moisture is observed in the motor oil.

At least crack the drain plug and look for water, as Jim suggests. Or just change it anyway and have done with it.

Yes, changing the oil cold is less beneficial than changing it with the engine warmed up; however, water in the oil is an EXTRAORDINARY CIRCUMSTANCE. Changing the oil and filter is cheap. Yes, the filters have gone up quite a bit lately; so have bearing kits!

After changing the oil, or at least ascertaining its integrity, start the tractor and let it reach operating temperature, keeping a close eye on the pressure gauge, of course. Warming the engine will help "cook out" excess moisture.

Replacement manifolds are available (try to get a unit cast in the US.

If threading will not work at all, and a new manifold is beyond reason, buy a ---schedule 80--- black Iron 2" NPT coupling and weld it to the top of the manifold with Nickel Rod.

JimN