Engime block

This is not my block but my original 4020 block was cracked between every hole just like this one . what would cause this and is the block still useable ?

I guess that years of heating and cooling causes it. It is not uncommon on 3020 and 4020's to find. Sometimes they will be cracked at the bottom also. Top cracks do not bother me if in my own tractor and I have overhauled some with bottom cracks as well. I have a 4020 that I started farming with that is cracked top and bottom between all six. I went to a salvage yard to get a used block and he told me to try a Loctite sealer either 505 or 515 (can't remember which). I used plenty in the oring grooves and up top under the hear gasket and it lasted for over 20 years as my big tractor. The head gasket seals on the sleeves and not on the block so the top in not a big issue to me. On a customers tractor I would want them to buy another block. Just my experience and I am sure other will disagree. Tom

I too have seen a lot of small top cracks and didn't worry about them,, the bottom cracks can be a problem..

Personally..cracked blocks scare me. However besides a 3400 telehandler I've not seen a John Deere engine block that was cracked unless it had thrown a rod or froze;

The telehandle I mentioned belonged to my neighbor. I'm not really certain what happened to it's engine block but suspect it either got hot or froze and busted. It's 4045 engine was cracked between all the cylinders from the top to down into the main bearing webs! The local Deere dealership had rebuilt the engine twice with new pistons and liners...plus worked it over a third time with new Timing cover and waterpump trying to keep coolant out of the engine oil...never noticed the engine block was busted

Somehow or other the owner decided he needed another mechanic...didn't even ask me about working on his telehandler. I would've turned it down...I had worked on the very same 3400 at the dealership and just hate-em(fortunately not many around!)! After spending a pile of money on the thing at the dealership(with no satisfaction) he just had his hired hand drive it over to my shop and the hand told me the whole sad story.

I thought about it a month or so and finally put it in my shop and pulled the oil pan(the only easy thing to get to on a 3400)...pressured-up the cooling system and it was obvious that coolant was leaking around the liners. Pulled the head and some liners and looked...Yep..bad busted block.

I was hoping he would scrap the thing...but no..neighbor had me install a Deere long-block. Now that fixed the coolant in the oil issue! I hate working on Deere 3400 telehandlers...

No personal knowledge but I've heard that some Masseys
were repaired by drilling through the block and squeezing
them together with all thread rods. Seems it was a common
cure. Webbing must have been different?

Are farm mechanic when I was growing up fixed a cracked engine block on a 4 cylinder Allis Chalmers pump engine that way drilled through the block between the cylinders and squeezed it together with all thread he used some type of epoxy as well on the top of the block

I have seen that on a lot of blocks. If it is just at the top they usually will seal and be OK. If it runs down the web very far then they will usually leak. As for the cause I think it is usually over heated in the head area. This can be because of a motor turn up and getting too high of combustion temperatures as well as just the water boiling.

Was kind of common on the early JD 4020 blocks on tractors turned up and running turbo kits. Some of those where turning 175 HP. Neighbor chopped with his for years turn up that way. I would replace the PTO clutch once each year. I went to stiffer springs and that helps some. That engine had every web cracked when I overhauled it. He would not spring for a different block So I put it back together and turn it down some. That has been 20 years ago and it is still running. No longer uses it as a "BIG" tractor but it still works.

I sent a Mack Thermodyne engine block off to some machine shop. The engine had chunked rods and knocked holes in the block. Somehow or another the machine shop put the humpty-dumpty Thermodyne engine block back together again!!..and it was fine

I will say that I(the poor mechanic) wanted a new or replacement block...but upper echelon say no...we fix scrap-iron...

5020'S Were good for that. JOHN DEERE SERVICE DEPT. said don't worry about that they all do .

That?s a lot of hp from a 4020 I thought mine was doing good at 112 hp.