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Old 05-27-2019, 07:41 PM   #1
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City: Raby Bay Marina. QLD
Vessel Name: M V Justace
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Heat Exchangers cleaning Cat 3208T 260 HP

Hi Guys,
Have just taken end off one and checked heat exchanger due to over heating last time out. Sure enough its blocked seriously!. My question is after looking at u-tube videos on various engines where they use the flushing method to clean the system, is this the easiest way to do this on both these Cat engines.
I have had to drop out two buckets of fresh water from the system to get the end cap off and would like to avoid doing that to stab engine if possible. My mechanic is not happy with me using the flush system because "the O rings need replacing and once cleaned may leak". Only one needed if I don't take any others apart. I have ordered replacement O rings and gaskets in case we do open all caps. As the exchanges are attached to header tanks its a major job to take them out....don't want to and can't afford to do that! Keen to hear from those of you in the know on how best to handle this problem. Robin

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Old 05-27-2019, 08:52 PM   #2
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City: Punta Gorda, Florida
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No experience on 3208 but, I have cleaned a heat exchanger on a 120 Lehman. I would expect the basics to be similar. I used barnacle buster and a spare bilge pump. Did a great job at cleaning the junk out.

I think Ski has used wooden dowels to clean exchangers as well and I would expect him to chime in. Dowels used carefully do not have the potential to attack the good metal as well as the junk. Good luck.


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Old 05-27-2019, 08:58 PM   #3
City: Anacortes
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If they are that clogged, Iím not a fan of trying to rinse them. No good way to monitor how clean they are getting and you will either not do enough or too much. If you think you wonít do damage with a weak acid, put a piece of brass in household vinegar and Leave it for a week and see whatís left of the finish. Even weak solutions left to soak can be too much. Which is why I prefer to pull the tube bundles out. If I recall itís the port side of the end cap. So one engine typically comes out easily. The other you may or may not have room. If you have properly cleaned the. At least once, Iíve typically been able to pull an end cap and rod them out with a small bore rifle cleaner. Pulling the whole heat exchanger is a bit of work, but Iíve done it as a winter project and bring them back perfect.

If you go to the hardware store you can buy a short length of abs tube just slightly wider than the width of the tube bundle. Makes it easy to boil them out in an acid solution. As they start to come clean, start gently ridding them to help the process along quicker. Wear a respirator and properly glove up. Better to bring them to a radiator shop and have them do this part safely.

If you have a mechanic who would rather not replace a frickin o-ring, well Iíd fire that guy quicker than I can snap my fingers. You will need more than just an o-ring. You need two gaskets on one side and one on the other. If the end caps are iron, inspect and donít be surprised if they are rotted. If they are the plastic style, follow cats torque recommendation. Brass was the best, but they were an expensive upgrade and might not even be available.

I unknowingly went over 200 miles on my first season and found the tube bundle to only have maybe 3 or 4 tubes actually flowing. I donít recommend it, but if you need to get through a summer at trawler speeds, they will easily do it. Rod out at least half of the capacity and then do it right in the off season.

Personally Iím not much for short cuts. Iíd do the cleaner for a follow up, but not as the primary means of cleaning a fouled unit.

If the engine is old enough and somebody used the old cat gasket cement, you will have the joy of sanding the gasket off, and it could be asbestos too. Be very careful to keep the surface flat. Mini nightmare.
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Old 05-27-2019, 09:05 PM   #4
City: Anacortes
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Sorry, just re-read and see your mechanic was actually arguing against flushing, so read that wrong the first time.

One last point. If you get ankles deep and find you just donít have the last 4 inches to slide the tube bundle out, the he unit is actually not that hard to remove. Itís just that they are north of 75 pounds and a pita to wrestle with. But, for reasons, I got to pull one off about 6 times in a row to get to the front cover. Your back wonít like you, but at some point itís just quicker and easier than continuing to wrestle over an inch or two.
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Old 05-27-2019, 09:45 PM   #5
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City: Raby Bay Marina. QLD
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Thanks Guru for your report and time.
The end plates are brass so that one good thing. I could try rodding them the holes are pretty small compared to others i have seen on U-Tube. No way I can slide the port exchanger out without taking the whole top tank with it so not going down that track. Starb one may come out into middle of engine room. May well have to go with mechanics way of capping both ends and soaking exchanger over night empty the solution into a bucket recap with new seals & gaskets and see how we go. Engine only went over 200 when I was giving her stick on way back home temp dropped when I went back to 7-8 knots. Finally I am a 73 yrs old reasonably fit but a little guy so no big mussels and my back would say stop pretty quick. Cheers
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Old 05-28-2019, 09:44 AM   #6
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Hire someone, not worth the pain you will suffer long after the job is done.

Do it correctly or cause some damage or breakdown somewhere inconvenient. Ghost’s advice is golden. Try flushing out with freshwater when you put her away, might delay the NEXT time you need to do this.
Don't believe everything that you think.
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Old 06-21-2019, 07:04 AM   #7
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I think that the best way to clean heat exchangers is to rod them first to open the tubes and then soak or circulate Barnacle Buster solution or similar.

I would agree with your mechanic if you had an after cooler but I suspect the 260 hp version doesn't. The chances of springing a leak in the o-rings due to acid are slight, the scale would have to be blocking an underlying leak. The consequences of a leak are not catastrophic unlike one in an after cooler.

So first rod the tubes so you know all tubes are open, then circulate BB solution through for a few hours using an old bilge pump in a bucket or something. Just filling and soaking the tube stack or bundle can also work, but I would do it 2-3 times as the limited acid will quickly get depleted.


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