Water flange on Universal M25XP corroded and leaked coolant

[ragtime]

Hi! I'm x-posting this from CruisersForum per Stu's suggestion over there. Thanks!

I have a universal M-25XP powering my 1989 Catalina 34. I have recently taken her from Seattle up the British Columbia coast to Desolation Sound and back down to the San Juan islands and have had two issues with overheating on the trip, issues that I wonder if might be indicative of a single root cause. I need some help figuring out that root cause.

1. When I was traveling north, just after leaving Point Roberts and about to cross into Canadian waters the engine overheated the first time. The fresh water pump had seized and the v-belt had melted on the edge of the frozen pulley and snapped. With spares for both the pump and the v-belt on board, as well as enough extra coolant, after an hour or two of tacking back and forth against the northerlies we were back under engine power. Things seemed to be working great, so I chalked it up to just an old pump.

Next 3 weeks: I checked the coolant every few days. It had gone down some and I assumed it was just air bubbles getting worked out.

4th week: Coolant level much lower than expected, had to add distilled water to fill up since no more coolant on board. Checked daily for leaks, couldn't find any. Coolant in the bilge so it's coming from somewhere. Bypassed the water heater circuit to rule out a leak along those lines.

2. Back in the San Juan islands now, leaving Stuart Island on my way to Friday Harbor it overheats a second time. Now there is a hole in the water flange, the part that houses the thermostat, that looks like the engine was shot (see picture). We sailed to Jones Island to pick up a mooring for the night, then on to Friday Harbor and dropped anchor. I've been there about a week now waiting on replacement parts.

The corrosion of the water flange definitely indicates to me something wrong and I'm looking for suggestions on how to troubleshoot that problem. Voltage electrolysis as described here: http://www.nitronine.com/diesel-engine-electrolysis-damage/ seems like a candidate, but I can't find anyone talking about this for marine engines or in these forums... is this an issue for boats?

Additional data that might be relevant:
   1. Boat is new to me as of January 2017, I have only guesses about the state and maintenance of her before then.
   2. Replaced a faulty voltage regulator with a Balmar MC-614 in April of this year, alternator was non-functioning for about 8 months before this due to bad voltage regulator. (maybe I did something wrong here?)
   3. I flushed the coolant system in June of this year: emptied coolant, cleaned heat exchanger with rydlyme, re-painted hx, replaced zinc in hx, replaced hoses, put in fresh coolant 50/50 ethylene glycol from an auto parts store
   4. Added solar panels in July. (maybe screwed this up... but it seems like a pretty simple process)

This ended up being a bit more than I meant, so thanks for reading this far! I think my questions can be boiled down to these two:

   1. Has anyone seemed something similar and can explain what happened to them?
   2. Does the troubleshooting route in the link I gave above seem like the correct route forward or are there other paths to follow?

Thanks!

-tony
s/v Ragtime

[Ron Hill]

Tony : I Have never heard of Diesel Electroless before, but it sounds very feasible.
Have you made the multi meter check as mentioned in the web site you posted??

That check should tell you if electroless is present or not.

A thought

[KWKloeber]

Tony

If you googleize the term you'll find other articles about it and procedures to check. I wouldn't think it would be more or less prevalent on Marine vs other engines (except of course that it's proven that sailors care more for their vessels than their autos) 😎

I don't know whether this is electrolysis or voltage induced galvanic corrosion. But as everyone here knows "electrolysis" is highly misused. We carry anodes (zinc, aluminum, magnesium) to prevent GALVANIC CORROSION of parts (strut, shaft, Hx) NOT to prevent "electrolysis."

Electrolysis is what happens to dihydrogen monoxide (splits to O2 + H) when you pass current through it, or did the experiment way back in HS. (We still had High instead of Middle.) Or it's also how your grandmother took care of her chin hair with a depilatory machine. 😳

-k

[lazybone]

Tony

If you googleize the term you'll find other articles about it and procedures to check. I wouldn't think it would be more or less prevalent on Marine vs other engines (except of course that it's proven that sailors care more for their vessels than their autos) 😎

I don't know whether this is electrolysis or voltage induced galvanic corrosion. But as everyone here knows "electrolysis" is highly misused. We carry anodes (zinc, aluminum, magnesium) to prevent GALVANIC CORROSION of parts (strut, shaft, Hx) NOT to prevent "electrolysis."


Electrolysis is what happens to dihydrogen monoxide (splits to O2 + H) when you pass current through it, or did the experiment way back in HS. (We still had High instead of Middle.) Or it's also how your grandmother took care of her chin hair with a depilatory machine. 😳

-k

Both my of my Nonnas outlived their husbands and to celebrate they dressed in black and grew out their beards.

[Ron Hill]

All : Whether it be electroless or galvanic corrosion  - it is NOT need by any boat owner!!  That stray current will eat up metal!!

Still recommend that Tony run some checks and get back with us.

A thought

[ragtime]

I have not run the tests yet, but I will be sure to do so and report back once I have her back together. I'm currently waiting on a gasket and everything seems to take a few days to make it to the island here.

I considered making a new topic, but thought I would ask here first. My heat exchanger was moved from bolted onto the engine to mounted to the fiberglass behind the engine by a previous owner. Now it is only connected to the rest of the engine via rubber hoses. Typically, does the anode in the heat exchanger provide corrosion protection to other parts in the system?

[KWKloeber]

Tony

Typically not, due to the fact that the electrical connection is poor. Exception is if a bond wire is run from an end cover bolt to engine ground.  Otherwise the anode protects the localized "battery cell" (the Hx.)