This week I completed a full aftercooler service on my Cummins QSC 8.3. I thought I’d share what I found. It had 3 years and 235 hours on it, and this was the first service. It looked better than I had hoped/was afraid of. This was in large part because last season my generator’s heat exchanger was completely blocked with scale. I think the regular fresh water flushing was a big factor - I have a flush port on the strskner cap and flush every time the engine is run.
For servicing I removed the core, cleaned it inside and out and reassembled using the Seaboard Marine aftercooler service kit and their protocol with lots of grease.
Observations
What I did for service
For servicing I removed the core, cleaned it inside and out and reassembled using the Seaboard Marine aftercooler service kit and their protocol with lots of grease.
Observations
- The instructions in the Cummins owners maintenance manual are very rudimentary.
- The bolt highlighted by the red arrow i. The pic below is tricky. You have to remove all the other bolts (including 8 under the AC), then slide it over to get access.
- 90% of the weight is the cooler core. The housing is very light!
- The rubber strips on the air side of the core are stupid. All they do is make it hard to remove the core.
What I did for service
- Soaked the raw water side in an acidic solution to remove scale. I left on the caps, poured in the solution, and let soak.
- After, flushed with fresh water and rodded out each tube with a gun cleaning rod/brush. Removed a lot a junk.
- Remove the core. A bit tricky and required patience plus some careful application of force. Also lots of Kroil penetrating oil.
- Soaked the remove core in a bucket of detergent to clean the air side then rinsed.
- Removed the dumb rubber strips for the air side of the core.
- Cleaned the caps of all old grease.
- Carefully sanded/polished minor corrosion from all mating surfaces with ultra fine sanding cloth, plus a lubricating oil. Also lightly sanded the inside of the housing to remove light corrosion.
- Liberally applied Alco Metalube grease to all mating surfaces plus the first 2”-3”’of the housing. This will make any future disassembly much easier and help prevent corrosion.
- Reassembled - it went back together very smoothly with the grease and light sanding.