Drilled Hole into Engine Block

Hi dejohnson88
Please let us know how you do effect repair on this. You have a lot of suggestions to choose from! Good luck!

Many, many valid points.....and truly a difficult decision.....
Besides the low but constant 15 psi of the water pressure on one side of the repair there may be a constant much higher pressure (oil pressure) on the other side of the repair. It should be possible to determine if in fact the hole on the backside coincides with moveable engine components and how much room there is behind it and how much space is available on the frost plug side of the hole. These distances woud dictate how much room is available for some kind of plug or repair. There may in fact be a "sandwich" type of plug which may be of more help than a treaded type of plug. But what will the thickness of the block at the hole site be able to bear? Another question to be considered is who is going to effect the repair. I don't want to comment on the posters skills but there is a hole in the block. If I were the one starting this post after my error I would likely be looking for a pro to remedy the problem. He will likely have to be paid. Not too many pro's would be willing to stake their rep on a risky repair. Not that a risky repair can't be done or wouldn't be effective. The question is who is going to perform it and at what cost with what assurances? The final answer will depend on what will be the most cost effective and best repair for the owner. I would'nt want to be in his shoes. Good luck to him!!!! I am sure all responses have his best interests in mind.

hav24wheel said:

Just because a dealer won't do the repair that way, doesn't mean it won't work, or last. Remember, dealers like to make $.

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Well true and false.
True: a valid repair could be one that a dealer would not promote.
False: It's not about money when the dealer has FULL liability to the outcome of the repair. For this reason they don't cheap out because that is what we call a "wedding ring", the problem will come back and never go away and it will cost huge money and time in the long run.

One other option I can think of.................. "pinning the hole".
A machinist can "pin" blocks and heads in areas where sealing is required and ample material is present. The cylinder walls are the original thickness so pinning can work with the area much like the original material.


If I were going to take an inexpensive route but utilize a repair that could possibly last, I would sleeve the cylinder or "pin" the block. Pinning would be my first interest since no more material is removed and it is probably the cheapest.

If I were going to sell the tractor in the future and I didn't want to disclose previous block damage (required by law in many states of the USA) then reloading a new block would be the way out.


Best of luck to you and I am really sorry for your circumstance.

And plaease go back to that someone that told you to drill the hole in the first place and explain the danger of doing that. Might prevent someone else from being in the same place ,, a sinking boat.

dejohnson88 I have been reading this since first posted read a lot of good ideas. eserver and aquaforce are giving you good information and the right way to fix it. The correct way hav24wheel hit one thing on the button concerning welding it. It is specific steps to welding cast. This is where I will give my 2 cents worth.I have been welding for 40 years. I started with boilermakers then transfered to pipefitters. I have welded everything weldable and some things people said is not weldable. Wish I was closer but I am in tennessee. If you decide to weld it GET A WELDER THAT IS CERTIFIED. SECOND SOME OF THOSE YOU STILL NEED TO WATCH because they usually certify on carbon or stainless pipe in most cases.Make sure he has welded cast and a lot of it when you put heat on cast it does crazy things. I have welded a bunch of it over the years engines, intake manifolds,exhaust manifolds etc.The problem you will run into is someone that thinks he can weld cast and really has no clue and when he finishes on the inside of cylinder where he has rushed will cause cylinder to swell you will try to start guess what happens when piston passes where he welded? It will bust cylinder or lockup. not everyone that says they can weld cast CAN. Hope I dont step on anyones toes, in my area and I do check no one in a engine repair shop really can weld cast. Wish you were closer I would try to help you.Hope it dont break you but do it right the first time. Sorry know I wrote a lot but one thing I can do is WELD and do it RIGHT.If you do have it welded ask him if he will need to peen it if he acts like he dont know what you are talking about DONT WALK BUT RUN. good luck let all of us know what you do.IT can be welded but not the wrong way. I tried to stay out of this one and keep my opinions to myself. Again good luck Handyman

dejohnson88 sorry for prior message being so long but didnt want to see you make a mistake in your decision about welding it and then still having to take it to machine shop to have repaired PLEASE DONT USE JB WELD THEN SELL TO someone without them knowing it. I wont post that long of a responce any more if you want to ask me anything about the welding process please send me private message so it wont take up so much time and space for people to read because it is certain things you have to consider OH YES NOT 40 YEARS JUST 35 or so. handy

handyman said:

dejohnson88 sorry for prior message being so long but didnt want to see you make a mistake in your decision about welding it and then still having to take it to machine shop to have repaired PLEASE DONT USE JB WELD THEN SELL TO someone without them knowing it. I wont post that long of a responce any more if you want to ask me anything about the welding process please send me private message so it wont take up so much time and space for people to read because it is certain things you have to consider OH YES NOT 40 YEARS JUST 35 or so. handy

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My opinion handyman , i'd like to see all you have to say about the welding process of it because that's what the site is about, giving an opinion based on knowledge and experience to try and help other Kubota owners out when in a jam. How many others had a similar experience and looked for some help, who knows? I like reading what you have to say and what others have to say on it, its teaches people what you should and shouldn't do sometimes.

Handyman you didn't learn to weld cast overnight, That you are willing to share your knowledge is pretty cool. Me and others on here like me appreciate what you are sharing and we thank you for it. Dusty

Thanks brokersdad and also to you dusty like your new blade to. I keep up or try to. I dont want to see dejohnson88 make a bad mistake cast is different and your rod choice and technique is not always the same most welders will go to welding supply and ask for Ni rod but sometimes that is not the best choice. Also its always possible to start welding in the cylinder wall area and inexperience will cause you to drop weld thru to cylinder wall and he would have even a bigger problem. Ihave brazed cast, tiged, and sticked according to the use from engine to my grandmothers pot bellied cooking stove ( darn that tells my age). Dusty if you ever get to the Smokey Mountains let me know.Good luck again dejohnson88

The saying “Fools rush in where angels fear to tread” may apply to me, since this my first post to this excellent site.

It appears from the recent posts of dejohnson88 that the hole is below where the piston last stopped. I would suggest you make an effort to deburr the backside of the hole before you turn the engine. Although I would expect the piston to break off any burr, it’s possible that a burr could get wedged between the piston and cylinder wall causing a gouge in the piston or wall if the piston moves down past that level.

Most of the suggestions so far seem to have concentrated on filling the hole in some fashion. I don’t think filling the hole, with possible negative side effects such as material extending into the cylinder, is necessary. All that’s needed is to seal the hole to prevent leakage. I suggest that bonding a small steel disk or plate to the outside of the hole can do this, somewhat akin to patching an inner tube. (Steel and cast iron have similar thermal expansion properties so there would be negligible thermal stresses.) I would avoid welding the patch for at least two reasons. First, welding involves heating metal to the melting point and I cringe at the thought of heat-caused distortion in a cylinder that has rather tight tolerances. Second, the comments that handyman made convinced me that it is a difficult welding task. I have not used JB Weld, but the web site claims it is an epoxy resin that is waterproof, oil resistant, and good for up to 500 F. In this application it would be used as an adhesive. A disk or plate provides plenty of bonding area to hold any expected load as long as the bond covers up to the edge of the hole. (Since the hole is only 0.125 inches in diameter, even peak combustion pressure would result in a load less than 30 pounds force.) Actually, if the hole is through the water jacket into the cylinder below the piston ring travel then the real load will probably be water pressure, and that would be forcing the repair tighter against the hole. If the repair leaked, you should be no worse off than you are now. The repair can be checked at any time for deterioration by “carefully” removing the freeze plug. If you were going to sell the tractor you could tell or even show the prospective buyer.
dejohnson88, good luck on whatever fix you choose.

He is going to put a blockheater in that hole so it would be as easy as screwing it out to inspect the repair.

eserv said:

He is going to put a blockheater in that hole so it would be as easy as screwing it out to inspect the repair.

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But if it did leak, water could get into the oil through the hole and do quite a bit of damage before it was discovered. I wouldn't trust any kind of adhesive to be reliable enough in this application.

I might be a little off base here on how everything is laid out and on my idea at all, but hey, sometimes thinking outside the box is needed. And sometimes the best outside of the box ideas come from people who don't know how to fix things on engines.

I would abandon the heater idea, at least on that particular plug. I would make a new plug to go inside the plug hole. Possibly with a tight fit, or if possible maybe even tap the hole. I dont know how much room there is before you hit the back of the cylinder wall. I would make that plug out of brass because it's soft enough to fill the hole when forced in. I would drill and tap a hole in the center of the brass plug. Maybe 10-32 I don't know what a metric equiv might be, but a small fine thread, but larger than the 1/8" hole. Then i would take a brass screw with that same thread and file, grind or turn a nice 45 degree point. The screw will then thread into the plug and align with the 1/8" hole in the cylinder wall. The point should go right into the hole and seal off the cylinder from the water passage. You would also have a lock not on the screw to lock it in place.

This may or may not work, but would do no harm in trying. It's easy to inspect and re-tighten. and if your hole is indeed below the piston ring level, this could be a good solution. just food for thought.

I thought about this quite a bit this afternoon while I was stripping paint off of my B8200 parts...

Good suggestions for a repair have been mentioned but IMO, most are applicable to an older tractor and not a relatively new Kubota. We also don't know if the OP is intending to attempt the repair himself or have it done.

If I were going to have it welded, I would at least remove the piston in the cylinder with the hole. If you're paying someone to do it, you're probably looking at a fair amount of cash already. I really don't see a cheap way out of this.

Sooner or later, the tractor will be sold. If it's repaired and disclosed, it may be very hard to get a good price for the machine. Personally, I probably wouldn't buy it even at a reduced price. Assuming it is disclosed and sold, somewhere down the line it won't be. I sure would hate to be the guy that goes to replace a failed block heater and notices a gob of JB Weld on the cylinder wall of my tractor...

If you replace the block, you'll end up with a reliable tractor again and it should retain it's value. If you use a band-aid, you're never going to trust the tractor.

Long story short, you're either going to pay now or pay when you sell and if the repair doesn't hold, you could end up paying a lot more.

paulg its not a difficult task for someone who knows how to weld cast and has done some of it. It would be a easy task for me, but I am afraid to suggest anyone to have cast welded unless they know the welder has a lot of experence with cast . I didnt want dejohnson88 to get someone that hasnt done a lot of cast and end up worse off. A lot of other people are also giving him good advice of new liner etc. I dont want him to get someone inexperenced and end up worse off. Wish he was closer to me. handy

Maybe it would be worth it for him to strip that block bare and shop it to you handyman to get it fixed right. Spend a little now, save alot later