Engine Anode Failure?
Hello Gulfstar 36,
I can see your anode problem, but I think you are missing the condition of your HE tubes!, I would say you are in dire need of a good flush/clean to get the HE Tubes working again to transfer the heat from your fresh water re-circ system to to the raw water running through your HE!.
You can actually make your own Anodes from Zinc Bar Stock, you can usually buy any diameter Zinc Bar from most anode supply companies to suit you application, you can cut them to length then use a suitable die nut to cut the corresponding thread to suit your Anode adaptor, as Xsbank mentioned, check them at 3 mth. intervals until you establish the eroding/loss cycle on your engine, I would also recommend an electrolysis test at some stage to give you an idea of your vessels negative mv value perhaps pre-slipping then post to correlate your normal anode replacement regime to see if you are within values that last the season?.
Please note: I do not recommend Muriatic Acid as a stripper for HE systems, reason it is very harsh on Aluminium etc. and is not completely neutralized simply by flushing with fresh or salt water, it can still carry on reacting with Aluminium etc. to their detriment effecting sealing surfaces etc. - There are safer solutions commercially available ie: Acetic Acid and Phosphoric Acid at the recommended dilutions with water that you can re-circulate in your Raw Water system that will strip the whole system without removing your HE, G/B Cooler, After Cooler etc. this process will save you money if carried out with the right concentrations and flow rates/direction etc. to regenerated your raw water systems ability to transfer your engines heat to maintain normal running temps, see att. pic. using Phoshoric Acid 5:1, these pics. were taken pre-flush then 2 hrs. later. on a Cummins 555, this process eliminates the physical removal of you engines HE's - G/B etc.
This flush rectified over heating symptoms immediately, the owner now carries out this procedure annually, I still recommend a physical check by removing HE end plates occasionally to confirm flush has been successful and to ensure health of HE Tube patency Silver Solder etc. and HE Housing.
I hope this helps?.