Heat Exchanger Replace - Yanmar 4JH3-TE

[BareProductions]

Hello,

Need to replace the heat exchanger on my Yanmar 4JH3-TE. The internet doesn't have great info on it (at least not where I'm looking). Anyone done this before?

Specifically:
- Is the heat exchanger held to the block with bolts or studs?
- Does the turbo have to come off first? I would think if the exchanger is on with bolts I could maybe just pull them and slide away from the turbo / exhaust rather than removing it all?
- If the turbo does have to come off are there any other associated parts that need to be removed that I may be forgetting?

Ordinarily I'd just start tearing into it. However, the boat is in GA and I'm in DC...so I'm trying to collect up all the right parts before hand and avoid leaving any necessary tools 10 hours away, ha.

Thanks!

[BareProductions]

Nobody? Once I start digging into it I'll try to post some pics here incase anyone else needs to work on one.

[sailormed]

No knowledge on the mounting questions you have. I was just wondering if you are going to replace it with Yanmar parts or are you going with an externally heat exchanger? After all it is just a big tube full of small pipes.

[jimbunyard]

Are you replacing the heat exchanger bundle or the complete H/E/manifold assembly?

The assembly is typically held on by 2 studs and 6 bolts. You might be able to get it off with most everything else in situ, but to put it back correctly, you must clean off all the old gasket residues and corrosion, and to do this efficiently, good access to the sealing surfaces is mandatory. It is generally a false economy to attempt to 'save time' by not removing attaching parts, but where to draw the line is sometimes not entirely clear...

From this image





I would say that removing the turbo makes sense, and maybe the alternator, rather than trying to fight with access removing the H/E, as well as alignment when replacing it (that's what the 2 studs are for on the H/E).

It may be easier to leave the turbo connected to the manifold/H/E and remove it as a unit, and separate them on the bench, if you're actually replacing the manifold...

Without having a parts manual in front of me, a bare minimum is exhaust manifold gaskets, H/E seals or gaskets, turbo/manifold gasket or seals and never seize. Depending on the age of the engine, spare clamps, hoses, wiring, belts, impeller, etc. might also be useful; while not particularly difficult, this is a pretty big job, and anything you can change 'while you're in there' will be a plus in the long run...

[BareProductions]

Thanks for the replies! Yeah I'm replacing with a stock Yanmar H/E unit since I've already got one.

Ok, I can see at least one stud in your picture. I assume there is one on the back end as well.

Yeah I'll def do as much "maint" work while I'm in there. I guess if I pull the exhaust hose from the elbow and disconnect the turbo oil lines I should be able to pull it as a unit like you say.

Think I've got all associated gaskets (exhaust, cap assembly, turbo/exhaust).

[Jeanneau 45.2]

BP: I have your engine in my 2000 Jeanneau. There are actually three heat exchangers: an engine oil cooler, a transmission oil cooler and an engine block heat exchanger. The first two are bolted onto the rear of the engine, and of course the last is atop the engine. Before I can offer advice, which are you asking about? Appears by your parts list to be the engine block heat exchanger, but wanted to be sure.

[BareProductions]

Yep this is the large block heat exchanger on the top / side of the engine.

I've got the 4JH3 with turbo but no intercooler.

[serendipitous]

I pulled the core from the heat exchanger on our 4JH3-TE several years ago without having to remove anything other than the end caps (and probably loosen the alt to slide it out of the way). I did find that some of the petcocks to drain the coolant first were brittle plastic which broke easily and ended up replacing them with newer versions that were metal (purchased from our local Yanmar parts dealer).

For context, I am not a mechanic although I am handy and did take the Mack Boring diesel maintenance classes.

[BareProductions]

Yeah unfortunately the H/E tank part is my problem. Got corrosion/cracking around an end cap and it's slow leaking. I patched it for a while with epoxy/silicon but want to get it fixed right.

[feebs]

I had same problem on my 3JH5E’s . Did same as you initially of epoxy & silicone but wasn’t confident it would last. All the radiator shops & mechanics I took them to stated cost of repair would be greater than the $3000 per new HE from Yanmah. So purchased two new ones.... lesson here is service end caps regularly by replacing end cap O rings. Once you see them leaking, salt water is eating away at alloy HE housing..

[BareProductions]

Hello all,

I finished this project last weekend. All went well. I ended up disconnecting the turbo-to-intake manifold pipe, exhaust elbow, turbo oil lines, and turbo coolant lines. Pulled the turbo. Disconnected all fresh water lines and slid the heat exchanger off the two fixed studs. No frozen bolts or hoses to deal with and all went smooth.

For anyone looking to complete the same project I'd recommend having the following on hand:
-Heat exchanger O-rings (2)
-Rear heat exchanger cap gasket (varies from year to year, see parts diagram)
-Exhaust manifold to turbo gasket
-Turbo to exhaust elbow gasket
-Turbo to intake manifold gasket
-Thermostat gasket (pretty much the only way to get the H/E front top hose joint off is to first remove the thermostat housing, best to have a new gasket ready)
-Crush washers (4) for the upper turbo oil line
-O-ring for the lower turbo oil line (although you can probably reuse what's there)
-Tube of gasket maker incase you bugger anything up.
-Torque wrench for the heat exchanger bolts (think spec is around 27.5 ft lbs)
-Open end wrench set and crow foot wrenches came in handy for hard to reach bolts

Depending on how your engine is situated, prepare to stand on your head for a bit, ha. Any questions PM me! I've got the parts manual and can provide part numbers if anyone is interested.