Hydrolocked? Yanmar 4JH2-TE

[Geoff54]

I've been busy so you have probably resolved all this by now anyway. And again, I'm quoting from memory because I don't have the manual available so.....

Theoretically you might be able to get away without completely removing the coolant pump but it has a projection that locates into the block and seals with an 'o' ring, so you would need to slide the head forward. In practice, I think you need to remove the pump.

IIRC there is a drain valve on the block but the quick and dirty answer is just to pull the bottom hose.

I think you should remove the heat exchanger and manifold so that they are out of the way and you have a good space to whack the head with a mallet to loosen it. There is also a raw water pipe immediately below the heat exchanger but I don't recall where the bolts are. Don't risk damaging it.

I did manage to undo and pull off my cylinder head by myself but it is quite heavy, so the more stuff you remove, the easier it will be. That heat exchanger is heavy just by itself.

There is a section on dismantling at the back of the manual that you have a link to. Unless you are sure that you can skip a specific item, I'd just go through the lists there.

The head will probably be stuck on and require some pounding to remove. You have removed the rockers and push rods, right? And there are a lot of bolts, triple check that you have undone them all.

How's it going?

[IsaakOker]

Originally Posted by Geoff54

I've been busy so you have probably resolved all this by now anyway. And again, I'm quoting from memory because I don't have the manual available so.....

Theoretically you might be able to get away without completely removing the coolant pump but it has a projection that locates into the block and seals with an 'o' ring, so you would need to slide the head forward. In practice, I think you need to remove the pump.

IIRC there is a drain valve on the block but the quick and dirty answer is just to pull the bottom hose.

I think you should remove the heat exchanger and manifold so that they are out of the way and you have a good space to whack the head with a mallet to loosen it. There is also a raw water pipe immediately below the heat exchanger but I don't recall where the bolts are. Don't risk damaging it.

I did manage to undo and pull off my cylinder head by myself but it is quite heavy, so the more stuff you remove, the easier it will be. That heat exchanger is heavy just by itself.

There is a section on dismantling at the back of the manual that you have a link to. Unless you are sure that you can skip a specific item, I'd just go through the lists there.

The head will probably be stuck on and require some pounding to remove. You have removed the rockers and push rods, right? And there are a lot of bolts, triple check that you have undone them all.

How's it going?

Yep, the issue is that 3 of the 4 coolant pump bolts that are in the cylinder head are round and very hard to get off.. So would like to avoid them for now..
I've Release the two that go into the block and are sealed by an o-ring. The bottom of those two screws released water/oil mixture which I found dmstra ge because it should be dry, right?

As for the manifolds, I was thinking of taking them off once the head is out as its really dirty in there and wanted to avoid as much undoing as possible.

The hose under the exchanger has been released ages ago and I can't seem to find the fresh water drain bear the oil filter so I'm going to try to pull it of and dry it out once all the cool t spills everywhere...

Hopefully can get it off in the next two hours as I'm in GA and night is upon me soon.

Also, thanks for the tip. Been following the section at the back the whole day hahaha

[IsaakOker]

Originally Posted by Geoff54

I've been busy so you have probably resolved all this by now anyway. And again, I'm quoting from memory because I don't have the manual available so.....

Theoretically you might be able to get away without completely removing the coolant pump but it has a projection that locates into the block and seals with an 'o' ring, so you would need to slide the head forward. In practice, I think you need to remove the pump.

IIRC there is a drain valve on the block but the quick and dirty answer is just to pull the bottom hose.

I think you should remove the heat exchanger and manifold so that they are out of the way and you have a good space to whack the head with a mallet to loosen it. There is also a raw water pipe immediately below the heat exchanger but I don't recall where the bolts are. Don't risk damaging it.

I did manage to undo and pull off my cylinder head by myself but it is quite heavy, so the more stuff you remove, the easier it will be. That heat exchanger is heavy just by itself.

There is a section on dismantling at the back of the manual that you have a link to. Unless you are sure that you can skip a specific item, I'd just go through the lists there.

The head will probably be stuck on and require some pounding to remove. You have removed the rockers and push rods, right? And there are a lot of bolts, triple check that you have undone them all.

How's it going?

Also, push rods, rockers and all 18 bolts have been released and taken away successfully

[Wotname]

IsaakOker, i'm all out of ideas at this stage but I do want to wish you good luck with this mission and I will be looking forward to hear the outcome once you find the problem.

[IsaakOker]

Originally Posted by Wotname

IsaakOker, i'm all out of ideas at this stage but I do want to wish you good luck with this mission and I will be looking forward to hear the outcome once you find the problem.

Thank you very much for all your imput.. Either today or tomorrow the head is coming off and then I'll post a few pictures to see how to continue as I suppose I'll have to turn the engine around to get the connecting rods out before freeing the pistons.

I actually think I might just pull the engine out as I will have to anyways at some point and I don't think that I will have to lever the crankshaft much anymore so no newt to have it fixed to it's mounts..

Only thing is that I've released all 18 bolts so to be able to lift the engine out, do I have to put all 18 bolts back or would 10 of them suffice?

Once again, thank you very much and I'll keep posting here daily

[skipperpete]

Originally Posted by IsaakOker

Thank you very much for all your imput.. Either today or tomorrow the head is coming off and then I'll post a few pictures to see how to continue as I suppose I'll have to turn the engine around to get the connecting rods out before freeing the pistons.



I actually think I might just pull the engine out as I will have to anyways at some point and I don't think that I will have to lever the crankshaft much anymore so no newt to have it fixed to it's mounts..



Only thing is that I've released all 18 bolts so to be able to lift the engine out, do I have to put all 18 bolts back or would 10 of them suffice?



Once again, thank you very much and I'll keep posting here daily

Try this link to the parts catalogue
https://www.marinedieselbasics.com/y...parts-catalog/
Sadly I don't see any replaceable liners in the block expanded view so that introduces a slightly higher level of difficulty.

[roverhi]

Get a piece of chain and a couple of metric bolts the same size but shorter than the head bolts. Use those bolts to secure the chain to the block and attach your 'come along' to the chain to lift the engine out. That's assuming the you've pulled the head. If you haven't pulled the head, stick a few of the head bolts back in to secure the head in place and use two bolts with the chain to lift the engine out. Don't know what Yanmar recommends but some engine mfg suggest you get new head bolts when reassembling the engine.

[Geoff54]

Originally Posted by IsaakOker

Only thing is that I've released all 18 bolts so to be able to lift the engine out, do I have to put all 18 bolts back or would 10 of them suffice?

You can certainly get away without replacing them all but why? It will only take a few minutes and it will spread the load of that heavy engine, reducing the risk of stressing a bolt or damaging the surfaces if the head breaks free from the block. Low risk but why not take a few more minutes?

Originally Posted by roverhi

Get a piece of chain and a couple of metric bolts the same size but shorter than the head bolts. Use those bolts to secure the chain to the block and attach your 'come along' to the chain to lift the engine out. That's assuming the you've pulled the head. If you haven't pulled the head, stick a few of the head bolts back in to secure the head in place and use two bolts with the chain to lift the engine out. Don't know what Yanmar recommends but some engine mfg suggest you get new head bolts when reassembling the engine.

Unless someone has removed them, there are lifting eyes on the cylinder head. And no mention that I've seen of Yanmar recommending replacing head bolts.

[IsaakOker]

Originally Posted by Geoff54

You can certainly get away without replacing them all but why? It will only take a few minutes and it will spread the load of that heavy engine, reducing the risk of stressing a bolt or damaging the surfaces if the head breaks free from the block. Low risk but why not take a few more minutes?






Unless someone has removed them, there are lifting eyes on the cylinder head. And no mention that I've seen of Yanmar recommending replacing head bolts.

Yep, now that I've taken the head off, I would put them all in to take the engine out.. Yesterday had a different feeling about it.

As for the lifting eyes, yes, there's on on the cylinder head and one on the heat exchanger which I would have to mount back on.

[IsaakOker]

So, I've finally managed to get the head out without taking the fresh water pump nor intake Manifold off as specially the water pump bolts are worn-out.

I'll try attaching some images so that you can have a look but basically looking from the crankshaft towards the gearbox, cylinder 1&2 look a little corroded on the walls & the other two were quite black.
All of them had a mix of marvel & coolant I believe although the oil wasn't white, it just felt like a mix of both.

The images were taken after pre drying them and after adding a slight bit of WD40 while I go to the store and get paper & penetrating oil to dry them out properly and let the oil sit for a day or two.

What are your thoughts?

[IsaakOker]

https://ibb.co/pdWzdDd
https://ibb.co/sPWG1m3
https://ibb.co/xXTc0PY
https://ibb.co/BrG1R4w
https://ibb.co/ydcdNyQ
https://ibb.co/sgWYj9N
https://ibb.co/v4L9BVP
https://ibb.co/FDNFwRC

[Cheechako]

Originally Posted by IsaakOker

https://ibb.co/pdWzdDd
https://ibb.co/sPWG1m3
https://ibb.co/xXTc0PY
https://ibb.co/BrG1R4w
https://ibb.co/ydcdNyQ
https://ibb.co/sgWYj9N
https://ibb.co/v4L9BVP
https://ibb.co/FDNFwRC

Well that pic 122503 shows some pretty bad cylinder wall corrosion. Or maybe I'm not seeing it well and it's just oil and rust on the surface?. The water must have been in there a while to do that, especially fresh water. At this point there is no harm in taking some scotchbrite and oil and trying to clean that up to see what is left. It appears that cylinder has a sleeve (?) So maybe it can be re sleeved. Are the other cylinders ok?
If you are in to fixing this I would have the head looked at and pressure tested, valves checked etc.

[IsaakOker]

Originally Posted by Cheechako

Well that pic 122503 shows some pretty bad cylinder wall corrosion. Or maybe I'm not seeing it well and it's just oil and rust on the surface?. The water must have been in there a while to do that, especially fresh water. At this point there is no harm in taking some scotchbrite and oil and trying to clean that up to see what is left. It appears that cylinder has a sleeve (?) So maybe it can be re sleeved. Are the other cylinders ok?
If you are in to fixing this I would have the head looked at and pressure tested, valves checked etc.

I'll clean them up when I'm back at the boat and will sen dnew pictures.

I took all these photos with HDR on the phone to highlight even more the contrast so it looks a lot more dramatic than in reality but I can slightly feel the corrosion patches on that cylinder, yes.

That's the one closer to the fresh water pump. Would that be cylinder 1 or 4?
I can't get to understand what is considered front and back of the engine...

[a64pilot]

Usually #1 is the front of an engine, the end without the flywheel.

[jimbunyard]

Does the engine turn over now?

I don't see anything in the top end that would preclude it from doing so; you're almost certainly wasting your time by trying to free it up with oil in the top of the cylinders.

As for what is holding it, at this point we're all just guessing. Did you take the raw water pump off as suggested?

When you removed and replaced the starter, did anything fall off the old starter and go into the flywheel housing?

Did the engine have oil in it when you initially tried to start it?

There's no need to put the head back on to pull the engine out. As previously advised, just take a head bolt to the auto parts or fastener store and get two that fit and are about a couple of inches or 50 mm or so long, and use those and a piece of chain to pull the headless engine out. It'll be much easier because of the reduced size and weight, and it may help to balance or angle the engine, as required for your application, in removal. The manufacturer-supplied lifting points are often not as well-placed for specific installations as they could be...

Though it's notoriously difficult to tell from pictures, there doesn't seem to be any serious mechanical problem with the top end, all the cylinders are equally carboned, and there are no apparent leaks from either coolant or compression in the head gasket, at least that I can see.

While you've got access to the freshwater pump and its' rounded-off bolts, remove and replace them or have someone else do it.