Cummins Marine Aftercooler Maintenance

Joint Custody

Well-Known Member
Sep 20, 2017
1,242
Lake Powell Utah
Boat Info
2001 460 Sundancer
Engines
Twin Cummins 6CTA8
Just wondering all your opinion.
If the boat has been in fresh water its whole life when should the after coolers be cleaned ?

Should they be serviced at the same interval regardless of fresh water or salt water.

Thoughts
 
I bought my boat in August of 2016 and had the raw water/cooling train "cleaned" as a condition of sale. In the Fall of 2018, I performed my first raw water/cooling train cleaning. This was approximately 180 hours of operation in a skosh over 2 years. They looked good! I cleaned the aftercoolers per Tony's recommendations and also had the heat exchangers "boiled out" at a local radiator shop. Also, I had the radiator shop pressure check the regreased/reassembled aftercoolers and also pressure check the heat exchanger. Going back with grease at the mating surfaces on the after coolers is the key.

I am scheduling my next raw water/cooling train cleaning for the Fall of 2021, which will be three yours of service. I am in a uniqure situation where I live in fresh water, and I can get to brackish water and salt water.

My methodology is to always keep the after coolers and heat exchangers on the same maintenance schedule. If you're down there, just do them all! Oh, and by the way, when the aftercoolers were off, I pulled the gear oil coolers. I had no records of them ever being serviced, so I erred on the side of caution. I replaced them with new. AND, since I had all of that equipment stripped off the engines, I went ahead and changed the T-stats while we were there. You have to drain off a portion of the coolant to remove the Heat Exchanger, so I went ahead and tackled the T-stats.

Jaybeaux
 
Just wondering all your opinion.
If the boat has been in fresh water its whole life when should the after coolers be cleaned ?

Should they be serviced at the same interval regardless of fresh water or salt water.

Thoughts

They don't need to be serviced as much in fresh water. My aftercoolers were serviced for the first time just after we purchased the boat. It was nine years (about 6 months/year in the water), all freshwater, and they were in good shape. The only thing that needed cleaning was the top of the cores as they had a layer of mud sediment on top of them from the Original owners too shallow marina. I took them apart again after 4 years, which included the time of our loop so there was 6 months of saltwater use. Again, very good shape, but I could see that just from 6 months of salt water use, the core had some (not a lot) of growth forming on the end plates. There also was some fouling from the anodes on the end plates due to anode erosion in the salt water. The cases were in fine condition. The marine growth and anode fouling could have been taken care of with a Barnacle Buster flush. We took the boat back south last winter and if we do not do any more salt water travel, I probably will not service the after coolers for another 5 years. For all fresh water use, I would do mine every 6 years or so, not that I think they would need it but mostly to just keep an eye on things.
The general feeling from the salt water guys seems to be every three years for them because of the corrosion that can happen on the air side of the cases from the salt air and to clean the cores good of the marine growth.
 
I firmly believe they need to be serviced every 3 years. It’s not a fresh or salt thing. It’s the corrosion of dissimilar metals from the copper core and aluminum housing. The grease is the key (alco metalube ) and it just doesn’t last forever. The aftercoolers are 3600.00 each so I would service them versus taking a risk when it’s really just an afternoon job anyway.
 
They still need the air side cleaned. I freshwater flush my QSC after every use. The last time I had the cooling system cleaned the Cummins mechanic recommended I have the aftercooler cleaned every three years and the rest of the cooling system cleaned every other time I do the Aftercooler.
 
Just wondering all your opinion.
If the boat has been in fresh water its whole life when should the after coolers be cleaned ?

Should they be serviced at the same interval regardless of fresh water or salt water.

Thoughts


My boat has lived in fresh water all of its life. When I bought the boat one of the first things I did was pull the after coolers and cleaned them. They had 17 seasons of service and looked like new. I cleaned them and put them back together. My plan is to re-inspect them in 2028 if I still own the boat.
 
If they had 17 seasons of use without cleaning you would have known it. If they looked new then they were recently serviced. Feel free to wait 10 years to check again but budget 7k for new ones if you wait that long. Now the key here is the metalube. If you service with that and you’re in freshwater I think 300-500 hours or 3 years would be acceptable. The new aftercoolers have a black coating on the interior so if you have those that’s another attempt to stop the corrosion from dissimilar metals.
 
If they had 17 seasons of use without cleaning you would have known it. If they looked new then they were recently serviced. Feel free to wait 10 years to check again but budget 7k for new ones if you wait that long. Now the key here is the metalube. If you service with that and you’re in freshwater I think 300-500 hours or 3 years would be acceptable. The new aftercoolers have a black coating on the interior so if you have those that’s another attempt to stop the corrosion from dissimilar metals.

After coolers had never been serviced. They are original. I have all the records for the boat since she left the factory. I did use the lube from Seaboard that Tony recommended.
 
Great lakes Pirate: If that's the case you're the only one of 20 boats with these engines I've seen. I would love to see a picture of your housings and core but it's definitely not typical.

JayBeaux: I wish I knew exactly. Its black. I think it may be aluminum black by birchwood casey but its just a guess... I got some aluminum black for touch up. It's a thin coating and it will flake off over time.
 
I have one new aftercooler with the black coating and drain holes and one old one without either of those things. I remove/clean every two years in salt. The black coating one is pristine on the inside when I pull it apart. The old style has a little more of the housing etch away each time. Even with the grease. I am saving my pennies to replace it with the new style. That black coating is some expensive stuff. When they added it the price of the aftercooler went from $1700 to $3400.
 
I have one new aftercooler with the black coating and drain holes and one old one without either of those things.

To those that have the new and improved version, are the drains self draining or do you have to manually drain them? If manual, how often do you do it? I have not seen any of these type but have heard about them.
 
To those that have the new and improved version, are the drains self draining or do you have to manually drain them? If manual, how often do you do it? I have not seen any of these type but have heard about them.

I have a QSB 6.7, and the aftercooler drain is self-draining. IIRC, it's supposed to drain when the engine is cooled down and there's no pressure in the aftercooler.
 
I asked my marine yard about this today since the boat is only a year new to me. The response: "Talked to our diesel tech and he said there isn’t really a recommendation since most recreation motors aren’t getting enough hours to need it. Unless you’re seeing issues with it specifically."

So, I may do this this winter just to see. Boat has been in FW it's whole life. Mike
 
To those that have the new and improved version, are the drains self draining or do you have to manually drain them? If manual, how often do you do it? I have not seen any of these type but have heard about them.
Sbmar told me I could add a fitting with a smaller hole to let the water drain out, but they recommended to just take the plug out every couple of months. Which is what I do. Sometimes it's dry. Sometimes a tablespoon or so of water comes out. But mine is on the easy access starboard side. When I put a new one on the port side I'll add the fittings since I really wont be able to get a wrench onto the plugs.
 
I have a QSB 6.7, and the aftercooler drain is self-draining. IIRC, it's supposed to drain when the engine is cooled down and there's no pressure in the aftercooler.

Just to follow up on my comment, I pulled this out of the service manual for my QSB. I'm not sure if the same would apply to other engines, or when this drain valve was added. Mine was built Nov 2017. While Cummins calls it a "check valve", my local service guy described it as a "drain valve" that lets condensation drain out of the aftercooler.

Inspect the aftercooler check valve when zinc anodes are checked. The valve should flow air freely under low pressure and close under high-pressure. A pressure of over 0.5 psi [3.45 kPa] from the threaded side of the valve should make it close. Operation can be checked using compressed air. The internal piston should rattle when shaken. Replace the valve if not operating properly.
 
I have the auto drain plug bill is speaking of. works perfect.
 
Great lakes Pirate: If that's the case you're the only one of 20 boats with these engines I've seen. I would love to see a picture of your housings and core but it's definitely not typical.

Must be due to our short boating seasons along with the cold fresh water that kept my coolers young at heart.
 
The condensate drain is needed due to the condensation created by the temperature change when the charge air is cooled. Just like the dew point. Engine off and low boost running, it’s open. You can feel charge air coming out at low engine speed. As boost pressure increases, the valve closes and seals the vent. Compression set takes place on all rubber. To that point, take the coolers off the engines and reseal them with factory seal kits. It makes a difference. Coolers that sit for long periods run the risk of the internal water drying and leaving it’s suspended particulate behind. It gets hard as concrete and plugs stuff up. Clean em out and they will live.
 
Question for those of you who do their own heavy maintenance IE after cooler, turbo and exhaust removal, what manual do you use and where did you find it. I down loaded a QSC 8.3 manual but its not specific to the marine version of the engine. I don't see a repair and maintenance manual at SBMarine.
My winter project is to remove and boil out my cooling systems.
Thanks
 

Forum statistics

Threads
112,943
Messages
1,422,704
Members
60,927
Latest member
Jaguar65
Back
Top