Got the engine rebuilt but the thermostat housing leaks!

Yooper Farmall · Dec 9, 2010

So finally got my "41 H engine rebuilt with new valves and high compression pistons. Reattached the manifold and carb, pressed the starter button, it turned over for about 2 seconds and fired right up!

We had a pretty big leak around the thermostat housing even though I put in a new gasket, a little extra gasket material fixed it, but now there is a little bit of fluid dribbling from the heads of the two 3.5" bolts that holds the two sections of the housing together. Is there supposed to be brass or copper washers or something to seal this up??

Yooper Farmall · Dec 9, 2010

Rebuild Project Pictures

Brownie 450 · Dec 9, 2010

Fel-pro recommends Pli-o-seal on bolts going into coolant areas. Just use Permatex #2 or blue silicon. Were both surfaces smooth/ flat? on the thermostat housing / head contact surfaces?

Yooper Farmall · Dec 9, 2010

They were relatively smooth, I sanded them clean but the housing had what I would call some slight mold flaws, either way we sealed the housing to the block with a gasket and some "The Right Stuff" gasket maker. The problem I am having now is coolant slowly dripping from the top of the housing, right at the head and lock washer for the 3.5" bolt that holds the two halves of the housing together. We were thinking maybe a rebuild gasket kit would come with some sort of copper washer to seal this up, maybe what I need to do is dip the entire bolt in blue silicon.

rustyfarmall · Dec 9, 2010

(quoted from post at 12:03:57 12/09/10) They were relatively smooth, I sanded them clean but the housing had what I would call some slight mold flaws, either way we sealed the housing to the block with a gasket and some "The Right Stuff" gasket maker. The problem I am having now is coolant slowly dripping from the top of the housing, right at the head and lock washer for the 3.5" bolt that holds the two halves of the housing together. We were thinking maybe a rebuild gasket kit would come with some sort of copper washer to seal this up, maybe what I need to do is dip the entire bolt in blue silicon.

To the best of my knowledge, the gasket between the teo halves is all there is to guarantee a seal. I am guessing there is some deteriation/rust pits, etc. that is preventing the gasket from making a complete seal. Rather than adding some gasket material, I think the solution would be to start with a new gasket and apply the blue silicon to both sides of that gasket before installing, and make doubly certain that the blue silicon goes completely around the bolt holes, while being careful to not get an excess of the silicon in where it could interfere with the operation of the thermostat.

Wayne in MN · Dec 9, 2010

No washer needed; the housing halves must be flat to properly seal. Just the gasket should do the job IF the mating surfaces are true.
Tape a sheet of 120 or 150 grit wet-dry abrasive to a glass plate & sand the parts (use water for lube) until each surface is completely flat.
I have a small table model belt sander that works great.

GordoSD · Dec 9, 2010

Why o why o did you mount that new rubber on those rusty old rims. Now you have to demount sandblast , prep and paint all over.

Gordo

Yooper Farmall · Dec 10, 2010

I bought the tractor as is, but they aren"t new tires, the backs are worn and weather cracked so badly that I am going to replace them. The cracks down show up in the pictures, but they might be 30 years old. The front tires aren"t new but I think I will keep them.
The rims are so rusted out that I"m going to replace them. So, old tires and rims out, new tires and rims in, no sandblasting needed!

pat in wis · Dec 11, 2010

looks like it has a lot of potential !

Got the engine rebuilt but the thermostat housing leaks!

Yooper Farmall

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Yooper Farmall

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rustyfarmall

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Wayne in MN

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GordoSD

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Yooper Farmall

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pat in wis

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