Hello, I have twin Cummins C series diesel's in my motor yacht that are approx. 17 years old with only 950 hours on them. They run great, but I've recently noticed seawater dripping at the end cap of the port heat exchanger (1 drop every 5 to 10 seconds). My mechanic is recommending I replace both heat exchangers at a cost of $7400 for both including labor and coolant. My question is, does this seam reasonable? It does look like the ends of the heat exchanger tubes have been JB welded once before. Can the leak be patched again? What are the ramifications of letting it go for awhile. Heat exchangers, aftercoolers and transmissions were serviced 5 years ago (approx. 300 hrs ago). Thank you in advance for help/advice. Bob
Do you trust your mechanic? Downside if they are bad is that you will destroy the motor when they do leak. Have them pulled, inspected and go from there.
Pretty much what Ess says, get them pulled and inspected. I just wrote on the Volvo 330 thread about the same thing, almost (I'm a Cummins dealer/ex-Volvo dealer). Get them looked at by an experienced engineer and get an unbiased appraisal for repair or change.
Thank you ESSRTEE8. So, it's probably not recommended to run them until I swap them out? Thinking of doing it myself as I found OEM exchangers for $1600 ea. and they look pretty easy to swap out.
You have a host of reputable boatyards in your NB to contact and at the minimum, get a recommendation for Cummins service. Basin Marine and Newport Harbor just to name a few. There is Seaboard Marine in Oxnard that has published a lot of information on Cummins issues: https://www.sbmar.com/category/articles/marine-aftercoolers/
ENPROEP, If it is the end cap on your "heat exchanger" they are available as replacements, http://www.mrcool.us/end-cap-4-inch.html If it is the "after cooler" these won't help, but after cooler parts are available also. https://www.sbmar.com/product/cummins-aftercooler-cap-for-c-series-engine/ Rich
If you have not solved the problem. The Cummins C Series heat exchangers have removal plates at each end and can be resealed with new gaskets and seals ( the seal is for the center bolt ). Check the plates for cracks ... change the zinc while you are there. If there is not enough room to remove the plates you may need to remove the heat exchanger. You should not need to replace the heat exchanger.