David,
I've been thinking about this posting for awhile and really need to respond as I feel very strongly you are putting out some very bad info, or at very least, giving mis-guided info based on a very limited amount of field data.
My goal here is to help all, not to disagree, but to show that what you are saying, has no basis in long term application--It's really no different than the couch engineers at Cummins that never heard the term "Marine Age" nor understood what really is going on inside any aftercooler of mixed metal construction in the field... What is "says" on paper , including "zincs" has ZERO value is real life or in actual application........ Here goes:
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Give me an honest & accurate answer on this one..
Tell me, as best you can, how many Cummins aftercoolers on mid-range engines you have put into service when new, (like you had from when the engine was brand new), and then maintained that engine over the next few decades, and then serviced the same aftercooler over and over throughout the years, by pressure testing it over 10 to 20 years on a regular basis, and then put together all those experiences together based on what you observed and tested over the 10-20 years that these base designed aftercoolers have been around? How many would you say?
What I am really having an issue with is your current thoughts on fresh water flushing and zincs.
On this subject—How many aftercoolers and engines have you worked on that spent 10-20 years in Lake Michigan or any fresh water lake and then had the 1st opportunity to take apart and service the entire engine-seawater side since launch date of the engine – 15+ years and/or about 500 total hours since new, or something similar?
Fill me in here as maybe I am missing something in the 30+ years I’ve been dealing with Cummins aftercoolers on the mid-range engines. Maybe close to 1,000 coolers later with notes and pictures of 100’s of them..
Help me help the readers on these forums to get this all into a true perspective based on real experiences over decades and not “one or two off” observations…
Tony