Aftercooler & Heat Exchanger Zinc Replacement Periods

[FSP]

Hello, I'm a new owner of a Carver 405 with Cummins 6BTA5.9 330hp engines. I'm just servicing my aftercoolers and found the zincs were either gone or well overdue for replacement. Fortunately, there were no issues with the housing and cores. I'm in salt water year round. I'm wondering what your experiences are with an interval on changing these out before it's too late and they are gone or are at the point they can't be extracted.
Thanks in advance.
Frank

[mjk1040]

Frank doesn't your manual suggest a change out interval. Also does it suggest what type of anode your should use based on the type of water you are located in? I'm guessing 3>5 years? Then again if you have no service records, the present ones may be the originals!

[Viper]

Under those conditions, you can't really put a number on a replacement interval as there are several variables affecting their longevity. My suggestion is that you pull the easiest one to get at every couple of months and once it's given up a third of it's mass, replace them all unless you're prepared to check them all at much shorter intervals. Under the right conditions they can go quickly but unless one of the variables changes suddenly, you should be able to come up with your own timelines after monitoring over the course of a year so you can add that task to you maintenance schedule.

The right alloy for your application is zinc though there is a move underway to aluminum for salt water as well.

[ssd1439]

I have the volvo tamd63's and I change them once a year at end of season and they are almost gone by then. I have 3 on each engine not too hard a job.