Update October 2022: Oh, FFS! The solution was staring me right in the face all along.

For those just tuning in, the backstory is this: When I first bought this sailboat, the guy I bought if from said, “Oh, by the way, you have to add a little water (a pint or more) to the radiator every time you start up the engine.” So, since October 2010, that’s what I did. Apart from being a pain in the behind, though, I alway had this nagging feeling that something wasn’t quite right about that. But it seemed to work, and I was intent on sailing, so the years rolled by.

But that nagging feeling never quite went away. So diving back into this fall, and after doing some research (actually reading the frickin’ Perkins M20 user’s manual thoroughly for once!) I thought the real problem with the missing coolant might have something to do with not having coolant in the reservoir underneath the galley sink (a related part of the solution, as it turns out), but there’s more to the story. 

I also thought, after reading up and studying the “caps” on the end of the pipe stack, that the assembly might be missing O-rings on each end (are there supposed to be O-rings?, I thought), to better seal the caps to the tube stack. I was getting closer. 

My new best friend and role model Ancil (the fellow sailor who lets me keep my boat in his pasture in the winters and a very mechanically inclined guy) came aboard as I was winterizing Splendido the other day, and I told him what I was up to, and then he said, “let me take a look at the engine.” I had already opened everything up, so I invited him into the cabin and he started examining the engine front and back. 

It Was Missing a $2 Hose Clamp on the Exhaust Side, Dagnabit!

At length, Ancil noticed something I hadn’t noticed in all the years I’ve owned the boat: the “cap” leading to the exhaust only had one (1) stainless-steel hose clamp instead of the requisite two (2) hose clamps — the missing hose clamp was the one that encircles the tube stack itself — so this oversight was allowing the cooling lake water and the radiator coolant water to blow right out the exhaust. (Fortunately, since we only sail four months in the summer, I have only been using tap water as coolant all these years because I didn’t want any antifreeze going in the lake. I just drained all the water out of the engine’s water course when winterizing every fall.)

Ancil tossed me a $2 hose clamp and suggested I get a wire brush (and maybe some steel wool) to brush away the corrosion on the male ends of the heat exchanger housing where the caps connect, and also using some dielectric grease applied to the rubber caps to help in sealing those to the heat exchanger. Then, tighten tighten tighten the hose clamps (all four, in this case) — especially the one exiting the tube stack, and that should fix things.

So, that’s what I did. Then, I topped off the tank with real 50/50 mix coolant (after gently hammering the rim where the radiator cap sits into perfect flatness, as it looked a little high on the front end), attached the fake-a-lake hose to the seawater intake thru-hull, and fired up the Perkins Perama diese engine. I let it run for about 30 minutes to get it up to temperature, then went full throttle for about 4-5 minutes on Ancil’s advice, to blow out the carbon that had built up in the engine. After shutting it down, I came back the next day and opened up the radiator cap, and voila: the coolant was filled right to the rim. For. The. First. Time. Since. I’ve. Owned. The. Boat.

Yes, folks, the Mystery of the Missing Coolant is finally — and somewhat embarassingly — solved.

Addendum: Filling the Undersink Coolant Reservoir

I should note that, before Ancil showed up, I filled up the coolant reservoir (no easy task — for starters, it’s incredibly hard to reach, as it sits on the aft wall underneath the galley sink, and it is quite high up. Access is through the cupboard door below the sink, so it took some serious contortions to get coolant into it. I started putting it in cup by cup, but then took a stab at slithering the 1-gallon jug throught the hoses and gently angling it toward the top opening. My back was beginning to ache, as was my core, so I grabbed the life sling bag and used that to cushion my backside. Ever so slowly, I was able to get the jug’s mouth over the reservoir opening and fill it about 2/3 of the way up. (Hint for next time: Use a sports bottle or get a shallow funnel to catch the spills.)

Happy to Take One For the Team
A lot of folks wouldn’t even admit to making such a bone-headed mistake as this one with the missing hose clamp, but if it helps even one sailor out there fix a similar problem, then I’ll take the hit and be happy that someone else doesn’t have to go through the same hassle as we did. Occam’s razor, folks: The simplest solution to a problem is the most likely solution. Painful lesson learned.

Fair winds and smooth sailing. DB