Cracked head, universal

[galway2004]

Learned that the universal 5424 on our sailboat has a cracked head. Coolant had been draining from return tank and oil test confirmed water/coolant in the oil. Only other thing we had checked is exhaust manifold which was in good condition. If we just replace cracked head i.e. don't take engine out and do a full rebuild, will our problem be solved? Interested if others have similar experience with similar engine. Trying to figure from a cost-benefit standpoint what we can/want to do. Thanks

[Lepke]

Don't know your engine, but have rebuilt dozens of diesels.
Coolant in the oil can result from a crack or a head gasket failure. Unless you can see the crack, the head needs to be pressure tested to verify it has a crack. All the coolant connections are blocked (head removed) and the coolant passages are pressurized, a gauge mounted, and wait to see if pressure goes down. This can be done by any shop that rebuilds heads.
A new head should solve the problem unless there's a crack is in the block.

[sailingunity]

I went through a similar exercise recently with my engine. I suspected a cracked head because I found coolant in the intake manifold (the only way I figured it could get there was by filling a cylinder). Took the head off and had it magnafluxed and pressure tested, they found no leaks but did replace some valve guides for me, the whole job was about $400. So yes it's possible to do this without removing the engine.

The problem turned out to be the coolant tank / manifold assembly, the mating surface between the tank and the exhaust portion was so thin coolant leaked between them. While the boat was on the hard all of the coolant in the manifold and the overflow take filled up the exhaust, the #4 cylinder and then the intake. I had a machine shop fill and resurface it.

[tkeithlu]

Welcome to the forum, galway.

Yeah, be sure that indeed it is a crack in the head. You want to find the actual crack, not throw parts at the problem. A crack can also be spotted with dye. There is no need to remove the engine unless the crack turns out to be in the block. If you have to replace the engine (let's hope not), find one like it. Changing engines can be a nightmare of hoses, cables, seacocks, and wiring all being in the wrong places.

Good luck with it.

[galway2004]

Thanks all, very helpful. Yes, we can actually see the crack in the head so leaning towards having that replaced and should fix out problem. Hopefully no other damage that we can't see, but really don't want to go through trouble of having engine pulled if we really don't need to.

[Island Time O25]

See if you can get the new head at Kubota tractor dealer. Probably will be half the price of marine parts dealer.

[FPNC]

Your engine should be a Kubota D1101. Start looking for a new or used head on the internets or a local Kubota tractor store.

[capt jgw]

You can actually get a whole used Kubota engine if you have too. Might be cheaper than just the new head. Lots of them on eBay and other sources. Just take all the "marine" stuff off the old and bolt onto the new. Transmission & bell housing, heat exchanger, exhaust manifold, water pump">raw water pump. A couple years ago I bought a used Kubota D850 and made the equivalent of a Universal M25 out of it. Works great. Hardest part of course is getting the old one out of the boat and new one back in.

[Cheechako]

Originally Posted by galway2004

Learned that the universal 5424 on our sailboat has a cracked head. Coolant had been draining from return tank and oil test confirmed water/coolant in the oil. Only other thing we had checked is exhaust manifold which was in good condition. If we just replace cracked head i.e. don't take engine out and do a full rebuild, will our problem be solved? Interested if others have similar experience with similar engine. Trying to figure from a cost-benefit standpoint what we can/want to do. Thanks

There is no way of knowing as we dont know why the head cracked.

Did it freeze?
Was the engine pretty good before or gulping oil?

Getting the head off may tell you quite a bit more. How gummed up is it inside and the head?
How much ridge is there at the top of the cylinders indicating wear?
Etc.
It should be an hour or so to get the head off so go for it!

If the head just cracked for an unknown reason, wasn't frozen, wasn't badly overheated, the probability of renewing the head and being "good to go" is pretty high in my experience of boats and cars.