Farmall M--persistent coolant leak after overhaul

After overhauling my M this winter, I am now having a persistent water leak into the crankcase. I took the head off and replaced the gasket. I also replaced the head studs with an ARP stud and nut set. Used spray sealer on the gasket and re-torqued after 10 hours.

When I took the head in to the machinist for the valve job, I asked him if it should be checked for leaks. He said if I wasn't having any problems before it should be ok.

I'm right in the middle of field work for spring planting, so this is really a bad time for this to happen.

Would using a block sealer in the radiator help for this? Can anyone recommend a particular brand? Any other advice I what I can do before tearing the whole thing down again? Thanks for any advice!
 
Pull the pan & see if you can find where it is coming from. There is a soft plug in the front that may be rusted through.
 
teddy---thanks for the advice. I will do that.

Can you elaborate a little more on this "soft plug in front"? Maybe a little more about the location? Is this something that is accessible after the oil pan is off? Is it behind the front engine plate? I can't seem to find anything about it in the M parts diagram....
 

You mentioned an overhaul. Was this just a quick in frame or was the block stripped down and cleaned?
 
I would lay odds that the head is cracked. If head bolts are not tightened down in the right sequence you may have cracked the head.
 
Get the head magna-fluxed for cracks. You probably should pull the oil pan to see if any coolant is dripping from the sleeves. Hal
 

If the head is still on you can look into the spark plug holes and see if coolant in on the pistons after sitting a few hours also.
 
who is this machinist saying a stupid thing like that. when a head is brought in it goes straight to the dunk tank and is soaked in caustic. then it is cleaned and inspected for cracks. then the normal work starts on it once it checks out good. it is part of the normal head rebuild. once a head is soaked cracks show up that are not otherwise visible.
maybe it is a backyard guy that just removed the valves and ground them.
the other thing to do is pull the pan and inspect around sleeves for leaks. even let it sit overnight with cardboard on floor to see if leaks appear.
 
Iknow thIS ISN"T the proper way or the the correct way, but is there any chance some good old Bars-Leak would stop it for a while? Only costs a few dollars.
 
I actually had a sealer running in the system in hopes of stopping the leak.

I purchased some Alumiseal yesterday and am going to give that a try.
 
Unless somebody bored the block and put wet sleeves in an M had dry sleeves. SO for it to leak by the sleeves the block would have to be cracked.
I would suspect the head is cracked or the head gasket is not fitting around the top of the sleeves right.
 
Mine did the same thing due to arp head studs were
leaking. Mine leaked on studs under the valve cover
which will put water in the oil. I drained the
water and pulled head bolts one at a time and
resealed with permatex sealer. Now evething is
fine.
 
went through the same thing with a H that was rebuilt ,due to sickness owner said it stuck before he was able to start it and never run until we bought it,we unstuck it ran fine then the water leak started,i replaced a new head gasket, block surface was good and had the head checked, machinist said it was good, i had it resurfaced anyway still leaked water into the oil pan,installed a large bottle of bars leak block sealer according to instructions ,haven't had any leaks sense but found out later there is a freeze plug behind the timing cover that's most likely the problem,when it decides to leak again then i'm going to replace it
 
I seriously doubt it is the head. Most likely cause is sleeves are protruding too far over block. That has become a real problem in last years. The head gasket seals across that sleeve flange, not all the way around on it. Second most likely cause is cracked block unless it is a very early block with the frost plug behind timing cover. The thing is you do testing before you tear it down. Once you pull the head you can't tell where it is leaking. I always pressurize the cylinders one at a time and if nothing shows up in radiator doing that, I drop pan and pressurize radiator.
 

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