yanmar 3ym30 overheating

[Solar Wind]

My 2005 yanmar 3ym30 overheats above 2600rpm. I have replaced the impeller, waterfilter/sieve and had the thermostat removed and it is still overheating, any advice

[Zanshin]

Is this 2600 rpm under load? You are most likely overpropped if this is happening while motoring. What is your speed through (calm) water at 2600rpm and which boat do you have ( the LWL is relevant).

[Solar Wind]

I have a so35 and the 2600rpm is under load. shes fine at full throttle in the berth. I believe there may be a mod required and should have been done under warranty

[Zanshin]

I think the boat is incorrectly propped. If you get hull speed (let's call it approximately 7 knots) at less then this RPM you will need to change the prop angle (if that is possible) or the gear reduction. What sort of a mod do you mean?

[Solar Wind]

I ahve been told that the early versions of the 3ym30 had a service recall to change the heatexchanger and i'm trying to find out if my engine is affected.

[Admiral]

I see so many boats motoring along with the owners blindly unaware that there is little water coming out of their exhaust or even worse steam!
The inlet hose could be increased from 1/2" to 3/4" (if yours is 1/2") and the other thing to do without delay is to withdraw the heat exchanger and make sure that it is not blocked.
This is a very simple task and is well worth doing. I have a feeling that this will help a great deal.
Admiral

[Full Circle]

The 3YM30 serial numbers under 5000 (in an SO35 this would be prior to 2006) are subject to a heat exchangers designed for a specific Coolant. Jeanneau supplied the worng coolant, and the silicates congealed on the heat exchanger.
2 things to note.

1. Yanmar will exchange your heat exchanger for a 28 fins per inch version, was free, but its been a while now.
2. Replace the coolant with the recommended, which is a Texaco Havoline Orange coolant. Here in the UK, that was difficult to find, but the equivalent is the OEM GM/Vauxhall/Opel coolant at around £5 per litre, which isn't too much to pay.

[Solar Wind]

Yanmar have agreed to replace the core of my heat exchanger but i have to pay the labour. Reasonable outcome i think. Thanks for suggestions

[Solar Wind]

Heat exchanger core replaced last weekend and engine runs perfectly at full throttle

[reverie]

Hello all,

I also have a early 3YM30 (#817) in my 2004 SO35. Last summer it began overheating after approximately 30 minutes while running above 2,800 rpm. The engine has 600 hours on it.

The raw water pump was dripping fairly badly - so perhaps air was getting sucked in by the pump and causing the issue. As a winter project, I replaced it last month. However, I also wanted to inspect the heat exchanger. I got both end caps off with little difficulty - although I did need to loosen the alternator to get at the fore cap.

However, I have been struggling to remove the bronze (copper?) spacers (gaskets) at either end of the heat exchanger. I think perhaps the gray paint Yanmar used to coat the engine is holding them fast. Hitting the front of the heat exchanger with a rubber mallet and block of wood is not budging the heat exchanger or the aft spacer - and I don't want to whack it so hard that I damage things. I also tried wedging in an old chisel between the spacer and the engine block, but gave up quickly when I thought damage was inevitable.

The good news is that the tubes of the heat exchanger look very clean - perhaps a function of sailing in fresh water. However, I would still like to remove the heat exchanger so I can inspect and clean the coolant side.

I've attached a picture (I'm pointing to the spacer with a screwdriver).

Any suggestions on how I might proceed to remove these spacers/gaskets?

Thanks,

John

[Don Reaves]

John,

Do you really have a 3YM30 in Reverie? My SO35 was commissioned within a week of yours at the same marina, and it has a 3GM30F engine.

Don

[reverie]

100% positive, Don. No mistake. Confirmed by the plate on the engine, the survey, and the documents that came with the boat.

Very strange that your's is different.

[j]

Dec 4, 2012 18:55:23 GMT reverie said:

I also tried wedging in an old chisel between the spacer and the engine block, but gave up quickly when I thought damage was inevitable.

Try using a sharp thin blade between the spacer

you'll probably cut up the o ring by doing that but I guess you would be replacing that anyway.

If that doesn't work you could try blowing some hot air on it with a heat gun briefly (which will soften any paint or sealant that's keeping it stuck on)

Let us know what works.

[celine3]

Hi
I just changed the heat exchanger so this is what I did to get it out.
See the 3ym30 attached file, page 1
The spacer #16 is actually fixed to the element #19 at the back of the engine. the spacer #16 forward is loose.
Here is what I did:
I made myself a wooden cylinder with a diameter slightly smaller than the element.
First of all I took off the exhaust/seawater mixing elbow to get good access.
afterwords i plied away the O-rings forward and aft.
Removed the forward spacer
Gave the wooden cylinder a very light knock with a wood hammer and I was able to pull the element off by hand at the back of the engine. Of cause some more force may be needed. But do not use any metal tools directly on the element or at the aluminium heat exchanger.

Once you have taken out the element you need new o-rings but they are inexpensive.

The parts list you can download here:

Attachments:

[reverie]

Thanks Celine3,

My challenge was that the spacer at the rear end of the exchanger was firmly stuck to the engine block (likely with the gray engine paint), so it blocked the heat exchanger unit from exiting the stern end of the engine. Several good whacks with a rubber mallet on a block of wood would not not make things budge.

After inspecting the tubes in the heat exchanger and judging that they were ok, I gave up and reassembled the thing.

Maybe Yanmar used a bit less paint on your engine.

John

[rick63]

I had a similar winter project. Given the whole system had to be drained I found it easier to remove the complete header tank and then the removal and refitting of the heat exchanger was easily achieved on the bench.

The reason I removed and cleaned it was the same SO35 overheat problem. I had the premod heat exchanger unfortunately my dealer would not replace as it was well after the original date. What I did find was a broken piece of impeller which was blocking about 20% of the tubes. The outside of the tubes were covered in a layer of slime. Every thing was cleaned, new O rings fitted and the whole assembly reinstalled.

This weekend I ended up motoring the last hour into a F5 at 3100 rpm and the engine ran great, no overheating. Previously anything over 2900 for more than 10 mins and the warning light came on. So a successful repair.

[reverie]

That's a great idea. Thanks. I will certainly take that approach if I feel the urge to access the exchanger again.

[sailbleu]

It's not always the heat exchanger that is giving some hardship , also the exhaust elbow gets blocked . Happened to me 2 years ago . Dont know anything about the yanmar setup in that department , but sand, calcium , or whatever substances pile up/clog up in the elbow, gradually and eventually closing the holes where seawater comes through cooling down the exhaust fumes.
That means no more cooling of the primairy circuit and a pressure build up in the rawwater pump causing seal leaks.
Just my 2 cents

Regards