6BTA aftercooler core

Just wondering what y'all think of this aftercooler core. My buddy just bought a Meridian 36 with QSBs. Strangely, the boat had two different types of aftercoolers. Anyway, I got the "luxury" of helping him take both of them apart...the first time I have done this personally. The newer AC had never been serviced(my guess) because it was an absolute bitch to get the core out. But once out, it was in excellent condition. The second one came out MUCH easier likely because it had been serviced before and greased up properly. I was just wondering about that ring of corrosion. Does that signify a leak? He will be pressure testing it anyway but just curious. Also no high amounts of sodium for either engine during the pre purchase oil analysis.

John,

There is almost always a certain amount of condensate that collects in the 'air' side of these vertically-oriented Cummins SWAC's. That ring is likely the level of the water that collects in that engine. The inlet from the turbo is located at the bottom of the housing just at/above that ring. When the engines run, any water in the aftercooler is drawn/blown into the engine. It sounds horrible, but it is essentially just humid air by the time it hits the intake ports. The latest Cummins aftercoolers even have a condensate drain port drilled at the very bottom of the housings.

Have it tested in a tank. But generally it's not good when you see that. I always err on the safe side even if they check ok. Because It will cause more damage when it fails and that's never cheaper than the new core. Also waiting for the problem to show in an oil samples is not a good thing.

BIG CAT said:

Have it tested in a tank. But generally it's not good when you see that. I always err on the safe side even if they check ok. Because It will cause more damage when it fails and that's never cheaper than the new core. Also waiting for the problem to show in an oil samples is not a good thing.

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He just bought the boat so it is not waiting for it to show in an oil sample. An oil sample was just done as part of the prepurchase survey and did not show any elevated amounts of Na.

BIG CAT, do you have experience with these engines? I certainly understand your point of "erring on the safe side". But in this case, that core is almost $2k! So if there is a way(which there is) to save the 2 grand, then that would be dandy.

Baker said:

He just bought the boat so it is not waiting for it to show in an oil sample. An oil sample was just done as part of the prepurchase survey and did not show any elevated amounts of Na.

BIG CAT, do you have experience with these engines? I certainly understand your point of "erring on the safe side". But in this case, that core is almost $2k! So if there is a way(which there is) to save the 2 grand, then that would be dandy.

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I'm not an expert on those specific engines. But I am a epg(generator) field service tech for a cat dealer in South Ms. I primarily do just gen work but do engine work when the other guys are tied up. I know what you're saying about the money. It's a hard pill to swallow but in my experience when something like that fails it does more damage down stream and ends up costing more in the long run. If you don't want to change them. I would at the very least keep a real close watch on them. You can get inspection cameras that plugs into your phone and can be a great tool for looking for leaks and whatnot.

Thanks BIG CAT. Yeah, a leak in this case would go undetected as it would just be blowing salt water/raw water right into the engine intake....obviously not good. But a pressure test would immediately detect a leak. He did pressure test them and they turned out fine. THe Cummins experts always seem to prep people something to the degree of "Don't freak out....there will be corrosion". But it is still disconcerting because the stakes are so high.

Baker said:

Thanks BIG CAT. Yeah, a leak in this case would go undetected as it would just be blowing salt water/raw water right into the engine intake....obviously not good. But a pressure test would immediately detect a leak. He did pressure test them and they turned out fine. THe Cummins experts always seem to prep people something to the degree of "Don't freak out....there will be corrosion". But it is still disconcerting because the stakes are so high.

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Ok. Sounds like that is common for them. They must use different core material than us. I know when we see that it's not good. I know I never like to hear the customer say "your other guy never said x". So I always explain the different options and potential for failure. It's best to let the customer make the final decision. And that's one of the reasons I love this field. No pressure to "sell" I don't make anymore or less money if they don't fix it.

Visit sbmar.com for good info on this topic.

BIG CAT said:

Ok. Sounds like that is common for them. They must use different core material than us. I know when we see that it's not good. I know I never like to hear the customer say "your other guy never said x". So I always explain the different options and potential for failure. It's best to let the customer make the final decision. And that's one of the reasons I love this field. No pressure to "sell" I don't make anymore or less money if they don't fix it.

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Good Information Big Cat, our flushing crew does similar they will suggest testing and get the opinion of the testing place and pass it onto the owner also. Some of the $$ are hard to swallow

Looks ok to me. Once assembled in the housing, put 30psi water into the water side and leave it sit for an hour. Check air side for any water, should be none.

And yes, condensation absolutely forms in these and will pool at the bottom.

Ski in NC said:

Looks ok to me. Once assembled in the housing, put 30psi water into the water side and leave it sit for an hour. Check air side for any water, should be none.

And yes, condensation absolutely forms in these and will pool at the bottom.

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Thanks Ski. I knew it was fine as I have done lots of research and have seen a LOT worse...that were also fine.

kapnd said:

Visit sbmar.com for good info on this topic.

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I have and I have given them thousands and thousands and thousands of dollars!!!

Baker said:

I have and I have given them thousands and thousands and thousands of dollars!!!

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So have I, and I count it as money well spent.
There is no guesswork in Tony’s shop!

kapnd said:

So have I, and I count it as money well spent.
There is no guesswork in Tony’s shop!

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It’s not rocket science. And it is appreciated for sure. But I don’t blindly trust one source. Just my nature. And he has been wrong before.