How do I clean a engine heat exchanger

[bluemax]

I have an Ericson 32-200 with a Universal M-25XP three cylinder diesel engine. The engine overheats after about 15 min. of running at 2500 rpm. I have checked the sea water pump and the thermostat and they are OK.. Water is comming out of the exhaust but maybe not as much as there should be. The fresh water seems to be circulating. The Elbow where the water is injected into the exhaust is only a few years old. So I think the problem must be the heat exchanger is fouled with sediments much like what builds up in a car radiator. Or there could be marine gunk in the sea water side.

So my question is: How do I dismantle the heat exchanger and how do I get the stuff out?
Is there anything I am overlooking?

This happened once before and I hired a service company to fix it. I wasnt present when the work was done, but I was told the exchanger was full of shells. I dont know if they were barnacles that grew in there or something that got sucked in. Neither seems likely.

 

[sailaway78]

Simple operation

Cleaning the heat exchanger is a pretty simple operation. There are commercial boiler de scalers available, and I have used diluted muiratic acid which worked well. Just disconnect your raw water hose from the intake, stick it in a bucket of whatever your going to use, and crank the engine. Be sure to shut off the sea cock. Soon as it sucks the bucket dry, put the intake hose on and flush with raw water. It's cheap and quick. OH You do not want to breath the fumes of any of this stuff.

 

[Maine Sail]

These photos will give you an idea of what you have and are dealing with. I prefer Rydlyme to clean the HX and it really works very well.

HX Photos (LINK)

 

[AXEL]

Be sure to have NEW end cap gaskets. If the end caps have been on for a while the gaskets will need to be replaced once you take them off. Don't find out the hard way! Also you might want to replace the end caps as well. Replace the zinc too. You should use Teflon tape around the zinc threads. I usually take the HX off the boat, remove the 2 end caps and blast water thru with a garden hose. That said, I would suggest taking the HX off and bringing it to a local radiator place and let them boil it out and pressure test. A few years ago I sprung a small leak in my HX. Lucky for me the place that manufactures most of the marine HX for the country is a few blocks away from where I work. I spoke with the guys there and they told me that the HX should be considered and expendable part. It's better to replace than repair. I bought a new one for $300.

 

[Steve Dion]

Remove the exchanger and take it to your local radiator shop. They will boil it & rod it out. You will need new gaskets, but they can get it a new lease on life.

Your other option is to open it up and try cleaning it with a gun cleaning kit.

 

[Stu Jackson]

Most of the time the tubes are fine. The buildup of salt occurs on the inlet port from the rw pump to the HX, where the salt drops out when it hits the hot water. Take it off, and shake it. If it sounds like a mariachi band, you'll have all sorts of gunk to clean out. If it is indeed an XP engine, it should be a 3 inch HX.

Also, check all of the hoses and the inlet thru hull for good raw water flow.

Can't understand how shells got in?!? You have a strainer, right?

Have you checked the rw pump impeller?

Here's a ton of good M25 engine info: http://www.c34.org/wiki/index.php?title=Diesel_Engine

Read this, too: http://c34.org/bbs/index.php/topic,4635.0.html

 

[Steve Dion]

Stu:

The shells usually come from shell fish. There may be some exceptions <g>!

 

[Dan H]

Cleaning the heat exchanger is a pretty simple operation. There are commercial boiler de scalers available, and I have used diluted muiratic acid which worked well. Just disconnect your raw water hose from the intake, stick it in a bucket of whatever your going to use, and crank the engine. Be sure to shut off the sea cock. Soon as it sucks the bucket dry, put the intake hose on and flush with raw water. It's cheap and quick. OH You do not want to breath the fumes of any of this stuff.

But it's OK to dischagre this stuff into the Gulf of Mexico?