RT 25 engine removal to clean heat exchanger?

[sereid]

Hi
Ranger tug 25 2012 - Yanmar 4BY2-180 engine, 650 hours
The engine is running without problems
On the last service I was told that my heat exchanger is becoming blocked and that to de-scale it requires taking the engine out. And that this is a good thing to do because then the oil pan can, at the same time, be checked for rust and replaced if necessary. Apparently, rusting oil pans on these boats, in general, is a problem (?). Please confirm that all of this is correct and reasonable.
Thanks!

 

[NorthernFocus]

Have you tried chemically cleaning the exchanger? And presumably they're talking about external rust on the oil pan? If so it's easily inspected with a boroscope that can be had on Amazon for under $50. Or if there's enough room an old school mechanic's mirror.

 

[sereid]

Thanks for the quick reply
Thanks for the tip on the Borescope - seems a lot easier (and cheaper) than taking the engine out...
I presume by "chemically cleaning" you mean running Ridlyme or similar through the system without having to remove the
heat exchanger? Can that be done with the 4BY2?
thanks

 

[NorthernFocus]

Thanks for the quick reply
Thanks for the tip on the Borescope - seems a lot easier (and cheaper) than taking the engine out...
I presume by "chemically cleaning" you mean running Ridlyme or similar through the system without having to remove the
heat exchanger? Can that be done with the 4BY2?
thanks

Yes. Flushing can be done on any engine with raw water cooling. If you're a DIY kind of guy it's not difficult. All you'll need some sort of circulation pump, a reservoir, some hose/fittings, a few feet of wire, and a couple of alligator clamps. A small bilge pump and a rubbermaid type tub will work fine. Also a good idea to put some screen on the bilge pump inlet so it doesn't ingest any large chucks of solids that might come out. Either size the bilge pump to move less water than the engine can pump at idle or put a valve on the pump outlet hose so you can pinch back the flow to avoid overflowing the raw water strainer and running into the bilge.

FWIW this is how I flush my engine with fresh water after every trip. Only difference is that without the chemicals I don't have to worry about overflowing into the bilge. On my Mercruiser(aka Cummins) a 750 gph pump is about right. With the boat on the trailer I just put the tub under the exhaust to catch the cooling water in the tub. The pump is in the tub with a hose routed into the raw water strainer. If you build such a system you probably want to test it out before charging it with chemicals.

If you don't/can't haul the boat out of the water it gets a little more complicated because you'll have to set it up to circulate without the engine running.

I'd post pictures but on this archaic site it's just too much hassle.

 

[Martin610]

I'm following this with interest.

I happen to have a 2013 Volvo D4-260, I have had a mechanic tell me the same thing. It is easier to remove the heat exchanger on the D4, I had to do it once already. It was a pain, but did not have to remove the engine. I do flush the engine with Barnacle Buster once a year or so.

From photos I have seen, the Yanmar might be more of a challenge.

Is your engine running hot?

Also, I thought the Yanmars had an aluminum oil pan? Doesn't mean it wouldn't corrode though.

It would be great to hear from experienced people and get their input on this.

-martin610

 

[sereid]

Thanks Both, very helpful info.
The engine is not running hot but apparently the heat exchanger had some build up. Sounds like to me flushing the system is the way to go.
Does anyone know if the oil pan on a Yanmar 4BY2 -180 is aluminium?

 

[irwinengineering]

While I am not sure of the access on the R-25, I can say that removing the heat exchanger and charge coooler on a 2011 4BY2 equipped R-27 was quite do-able with the engine in place. Look through the diagrams here to get a sense of where the fasteners and hose clamps are to determine if you can get to them http://www.marineengineering.pl/wp-cont ... 801_en.pdf .

This spring while changing the engine mounts I also did a full dismantling/cleaning of the cooling system, some details here viewtopic.php?f=5&t=14872&p=143424&sid=a36dab8e11acef2631ba44402e89302e#p143424. The heat exchanger was pretty easy to get out, the charge cooler had some bolts on the bottom that were difficult to reach.

After fully descaling the internals, I reassembled using thick grease as detailed here https://www.sbmar.com/articles/cummins- ... intenance/. The o-rings were not as special as Yanmar would have you believe with their $24/each pricing. They were easily sourced from McMaster Carr, all delivered for less than $20/total.

Good luck,
Brendan

 

[sereid]

Bendan,
Many thanks for the links and the advice - much appreciated. Hopefully I will get this sorted out. I found information saying that the 4BY2 has an aluminium oil pan, so rusting there is presumably one one less thing to worry about!
Thanks again.
SR

 

[CaptT]

A mirror view of the oil pan can help but placing a magnet on the surface of the oil pan should tell you if it's aluminum or not. The flushing of the heat exchanger worked for my D4 260hp Volvo. I took out the impeller and connected some cheap plastic pipe to a bilge pump then to the intake, raw water line, and let the disconnected exhaust water line drain into a five gallon bucket. I used Barnacle Buster and let this recirculate for a couple of hours. The discharge water was black and " chunky".
The moral to the story??? You can make a big difference doing a flush like this.
If you want more info on how to do this either PM me or try looking on YouTube, they have some great videos on this.

Good luck!