Heat Exchanger Challenge

[Dan Corcoran]

I have the version of the 3YM30 where the heat exchanger is on the port side.

After removing the three bolts on the front face (not to mention removing the alternator), the small front plate in front of the heat exchanger element won't come out.

Can't find a way to get any purchase. Any ideas?

2007 Hull 332.

Dan

[Vento Solare]

See figure 15 on page 19 of the parts catalog. I would use a wooden block and hammer on the edge of the bonnet inlet to try and break it loose.

[Dan Corcoran]

Position wood / hit it in which direction? Sheering left to right?

[Vento Solare]

Try and rotate the flange to break the seal.

[TSweather]

If you remove the top step from the companionway you should have more room to work in there. I would use the wood with a hammer from multiple angles to try to break it loose. Possibly some penetrating oil as well.

[Dan Corcoran]

Would you believe it self disassembled, simply leaving it on the workbench it came apart on its own, the two ends fell off.

Next up is to slide out the heat exchanger, it isn't moving.

Does the newer heat exchanger matrix on the 2007 engines slide out, like it does in the video of the older yanmar heat exchanger? There are sevearl things that do not match the helpful 109 video on youtube, including what side of the engine it is on.

Dan

[Dan Corcoran]

For the 3YM30, some things I learned to share:
There were not many skills needed. Completing a general marine diesel class is a reasonable prerequisite so you know your engine before getting started. Lots of caution is needed. Although the acid did much of the work, it took me 16 hours to complete it: 3 hours to disassemble, 8 hours at home, and 5 hours to assemble. Doing this the first time, don't expect to complete the work in under 4 days.
- Taking pictures before getting started was insufficient to capture all the electrical connections to the alternator, take the effort to write them out also.
- Purchase all parts in advance, I went to toadsmarine for parts. Stock is awful, had to wait 10 days for some parts (October 2024)
- Plan to remove the entire heat exchanger assembly from the engine when purchasing parts like gaskets attaching to the engine and exhaust.
- There is a video of the heat exchanger being cleaned by a J109 owner, watch it. Very good. Note however, it is a different engine. The heat exchanger is now on the port side, and no longer divided into two chambers at each end cap, so there is no bar gasket, rather they are simply round x 4 of them.

- Expect to use 3 gallons of CLR. Expect to spend more time on this step as you discover more parts you want to remove rust from
- Don't get carried away removing rust. The bolts for example lose their gold coating even after a short time
- 2 hours is good starting point for the first immersion in CLR for most parts, then add time as necessary.
- When at home and removing the six bolts at each end, just let it sit a couple of days, it becomes easier to take apart. Also be familiar with which way the heat exchange slides to understand which direction you want to use force.
- Like in some of the vidoes, give the acid wash a head start, by first cleaning each of the individual tubes with a rifle cleaning kit. This is what I used:


- A dremel tool with 515 bits (180 and 280 grit) was useful too.
- Putting it back together is a two-person job. Attach the gasket between the engine and assembly with two long strips of electrical tape that you can pull completely out after you get a couple of bolts in. A person in the cabin supporting the weight from underneath leaves the person above to drop it in, line it up, and push the first bolts in.