Heat Exchanger

[WindLove]

Maybe if I don't have a problem I should leave well enough alone but.... Recently I went to a discussion on Diesel engines and the guy said one of the most important routine maintenance tastes is to remove and clean the heat exchanger. He said the little tubes would get clogged and the engine would start to overheat.

I think it's been years since the heat exchanger has been removed. If everything seems to be working fine, is this something I should proactively do. How difficult is it to remove the heat exchanger, and what is involved in cleaning it. Is this something better left to a mechanic?

Any advice?

[Sailmonkey]

Really depend on what engine as to the ease of cleaning, but in a lot of the engines are oI-rings that become hard over time allowing seawater and coolant to mix (in impossibly small quantities).
If regular (for me every two years) tube bundle pulls are part of your routine then ease of pulling the tube bundle is increased.

[Pirate999]

Of it's not broke, don't fix it.

[skipmac]

Not sure if I would call it one of the most important routine maintenance jobs but if your engine overheats then it will quickly move to the top of the list.

How hard it would be will depend on your engine and how long it has been since the job was done. I recently cleaned out mine on a 30 year old Westerbeke and it wasn't too bad. Considering the lack of recent maintenance when I bought the boat it had probably been many years (if ever) since it had been cleaned.

The water hoses to the exchanger were old and hard so I ended up having to cut them off. They needed replacing anyway so no loss. On my engine it was attached by a couple of brackets and hose clamps so after the hoses were off it removed easily. It has been over a year now so details are getting fuzzy but I don't remember any serious trouble removing the end caps to access the cooling tubes.

At that point it was just a matter of a little rinsing and poking with a long metal rod and various tools to clean out the deposits but it really wasn't blocked up to any degree and I probably could have gone for years without a problem.

If you can run your engine hard under full load and the temperature doesn't go up at all you are probably not in imminent danger of burning up the engine. But if you have no idea how long it has been since the heat exchanger was cleaned and you have nothing else to do (yea right, you have a boat so when does that ever happen) then not a bad idea to take a peek.

[GordMay]

Yanmar Heat Exchanger Servicing (2GMF / 2GMF20)
Yanmar Help ➥ HEAT EXCHANGER

[DeepFrz]

Expressions like "if its not broke don't fix it" are what lead to overheated and possibly destroyed engines. Taken to extremes one would never change the oil, for instance. Routine maintenance, done properly, will keep an engine running properly for years with very few problems to fix.

[athene]

My engine is a Volvo Penta MD30A and advice from the professionals is to clean the heat exchanger at least every two years. I cheat a bit, since I don't take it off the engine unless it really needs a good clean out. On the Volvo, you simply remove the front cover and I then flush it through every year in situ with a hose clamped to the pipe outlet at the back end (i.e. against the usual raw water flow).

I only remove it from the engine if on inspection it's badly encrusted with salt - which doesn't happen in my experience if you flush it annually.

Also I flush through the entire raw water system with a freshwater/antifreeze mixture and leave that in for the winter to kill any marine organisms lurking in the heat exchanger and engine cooling channels.

[leftbrainstuff]

Follow the OEM guidelines in the first instance. For a system with an unknown history then i build 3 lists.

The first is must do list. This is your corrective maintenance list and is primarily for stuff that is broken or at end of its useful life or poses unacceptable risks to use or have.

List 2 is your will do list. This is for planned maintenance that you will do at a time and place of your choosing.

List 3 is a wishlist. It allows you to add stuff you want but that isn't critical for safety, efficiency or ease of use.

Prioritise the lists and start at priority one and work down. If you ever get to the bottom, don't relax. Rebuild the lists.

[skipmac]

By the way, here is a link to a step by step how to guide with photos, published by forum member Maine Sail.

Autopsy A Westerbeke / Universal Marine Heat Exchanger Photo Gallery by Compass Marine at pbase.com

[bletso]

Don't forget the zincs!

[twistedtree]

The more critical "heat exchanger" is the aftercooler if your engine is so equipped. If it starts to leak because of hardened or failed o-rings, or any other source, the engine will start ingesting seawater which is very bad.

[twistedtree]

Oh, the other reason for regular maintenance is to keep them lubricated so it's possible to disassemble them. If left for too long they can end up completely seized up and impossible to take apart without damage. Then you are replacing it.

[lancelot9898]

It's been over ten years since I've removed the heat exchanger for cleaning. As long as the coolant temperature is within spec then there really is no need for cleaning. I have a Perkins 4-108 and during the 25 plus years of ownership, I removed the tube 3 times over the years when high temperature reading were noticed on the gage. I put the tube into a muric acid solution for just a few minutes, then baking soda to neutrilize the acid and finally rodded the small tubes with a gun cleaning patch. It's really easy to do in the case of my diesel and while maybe most requite a zinc, this particular model with the rubber end caps on the bowman heat exchanger does not.

[Stu Jackson]

My experience is that it is rare that the tubes get clogged, since the water is moving through them pretty fast. Check the inlet port on the HX from the raw water pump which is where you are liable to find blockage from the salt dropping out of the cooling raw water. That's why I suggest people remove their HXs every few years to check that possible build up.

[WindLove]

Lots of great, if conflicting, advice. It sounds like it would be a good think to do.