Upgrading my Universal/Westerbeke Heat Exchanger: The dumbest repair I’ve ever made

This is a tale of folly and failure. My lack of research and trust in manufacturers led me down a long path of woe.

Universal5424

The Universal 5424 in our 1982 O’day 34 was overheating. The 3-cylinder diesel motor was rated to run at 2800 RPM. However, if we pushed it past 1900 RPM, the temp needle began rising and never stopped.

Decades ago, Universal/Westerbeke admitted that the 2″ diameter heat exchanger was too small for the 5424 and the M-25 and recommended upgrading to a 3″ heat exchanger. Despite our engine allegedly being rebuilt in 2008, that never happened.

At the very beginning of this debacle, a friend said I should just buy a cheap generic 3″ heat exchanger with screw-in bungs, so I could size them to my hoses and just do a quick swap. I decided against that because I wanted to keep the engine as OEM as possible with an “official” upgraded part, and I thought finding the barbed bronze bungs might be a pain. Oh, how foolish I was.

Catalina Direct had factory style replacements heat exchangers starting at $500, but I wasn’t ready to pay that much, so I searched eBay. One seller claimed he had a 3″ Universal heat exchanger. It looked very similar to the one I had. I made an offer at $150 (plus $20 shipping), and he accepted! I probably should have paid more attention to the last line in his auction that said, “measurements are not exact.”

A few days later the eBay exchanger arrived. It did look very much like the one on my boat — because it was the exact same 2″ diameter heat exchanger mounted on the back of my motor.

I contacted the eBay seller, and after a photo with a measuring tape showing that he had definitely listed this part incorrectly, he agreed to refund my money. Unfortunately, I had to spend another $20 to ship it back.

Before the project even started, I was down $40.

I browsed the Universal/Westerbeke options on Catalina Direct, and they all had the same hose inlets/outlets listed. I took that to mean they were standard sizes that would be the same as the heat exchanger I was removing. That was a terrible assumption.

heatexchanger01

Approximately $550 later, I had this 3″ x 17″ behemoth that didn’t share a single intake or outlet size with my old unit. In fact, despite being the “factory” upgrade, some of the outlets didn’t even point the correct direction.

I slowly began the process of adapting the hose sizes and directions to make it fit.

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Why have four hoses and eight leak points when you can have 15 adapter pieces, nine hose sections and 63 leak points?

The worst part of it all was the 7/8″ raw water intake port. My oberdorfer pump had a 1/2″ barb and hose coming off of it. I found a 3/4″ barb, but a 3/4″ hose will not fit on the 7/8″ intake — even if you boil the hose first. There are no 7/8″ fittings available ANYWHERE.

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I ended up running the 1/2″ hose to a 3/4″ adapter and then triple clamping the 7/8″ hose onto that to keep it from leaking. However, since the soft 7/8″ inlet got slightly out of round as the heat exchanger was being moved around for three weekends, the 7/8″ hose doesn’t make a perfect seal on it, and I’ve now got an ever-so-slight drip of sea water leaking into my bilge for the rest of my life.

Another $500 in adapters and hoses later, I finally had the entire coolant system put back together.

Since I had to drain all the coolant anyway, I decided to replace my thermostat.

thermostat

That was an easy process, but you have to special order the molded hose that connects the thermostat housing to the water pump. Be aware of this fact ahead of time because if you’re not, you have to put the project on hold for another week while you wait on that hose to show up.

Once I finally got it all back together, I fired up the engine, and it promptly overheated.

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Yes, I had an airlock. I did not know that after filling the coolant system, you must remove the bolt in the top of the thermostat housing and then pour more coolant in there to remove the air pocket.

After overheating the engine twice dealing with the airlock, I finally got it running. We ran it in the slip long enough to verify the thermostat was opening correctly, and that she wouldn’t overheat anymore.

It took three weekends and about $1200 after the expense of the heat exchanger, hoses, adapters, clamps, thermostat, and impeller, but we can finally push into the wind at 2200 RPM without overheating.

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Our last time out in that type of wind we were running at 2 – 2.5 knots. Making trips down to Galveston in a strong headwind were completely out of the question. Now we should be able to plan trips at an average speed of at least 4 knots no matter what the weather is like.

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We still don’t have one of those speed demon sailboats that can motor at 6.5 knots, but four is twice as nice as two. However, if I could do this project again, I definitely wouldn’t be so freaking dumb.

Don’t be like me. Get the generic heat exchanger and screw in the barbs that fit your existing hoses. You can even get 90-degree nozzles and twist them to the exact direction required.

I’m going to apologize now to any future captain of Gimme Shelter. Projects like this are the reason people hate previous owners.

 

 

Maintaining the raw water system: seacock, strainer, impeller, zincs

My sailboat to-do list has been growing all year, and there was no way around it, this weekend I had to do some maintenance and work off some of my lingering projects.

Universal 2420 Diesel

Auxiliary power on Gimme Shelter is supplied by the original 1982 Universal 5424, a marinized Kubota diesel. This weekend I decided to work through the raw water system.

Raw water seacock

I checked to make sure it moved freely open and closed. I checked the hose for cracking, and I checked to make sure the hose clamps did not show any signs of corrosion. Everything looked fine, so I closed it and moved on to the next piece of the system. (Closing the raw water seacock is a key step in all raw water maintenance and repair, as is opening it before you start the engine again!)

Raw water strainer

The strainer is basically a jar with a metal basket inside. Water is pushed through the top of the basket, and then shoots out all of the tiny holes of the metal strainer while leaving debris inside the metal strainer basket. If you look at the photo above, mine is very easy to access on the port side of the engine. I pulled out the strainer basket and found just a little mud, sprayed it with the hose and put it back together. No problems.

Raw water pump impeller

It’s recommended that you change the raw water impeller annually. I hadn’t had any water flow issues, and we hadn’t put many on hours on the engine, so I had let Gimme Shelter go two full years without replacing it. It was still working, but when I pulled it out, I could see the difference between the old and new impellers.

impellercomparison

I really like the Oberdorfer pump because it’s easy to access on the front of the engine, and it only takes four screws to open it up.

rawwaterpump

The impellers just push onto the keyed center shaft, and you’re ready to go. The only catch is that you have to replace the paper gasket every time you open the pump. You also have to make sure you remove all of the old paper gasket before you install the new one or you won’t get a good seal. In the past I have resorted to cutting a new gasket out of construction paper with a pocket knife, but it’s definitely easier just to order a new gasket when you order the new impeller.

Sacrificial zinc anode

From the pump, the raw water moves to the heat exchanger where the antifreeze moves through tubes and transfers the heat of the engine into the seawater before it’s sent overboard in the exhaust. A sacrificial zinc anode is screwed into the heat exchanger to protect it from corrosion. If the heat exchanger tubes corrode out, you’ll end up with seawater in your antifreeze and vice versa, so this zinc is very important.

I’ll admit it. I’d been as lazy about the zinc as I had been about the impeller, and it hadn’t been changed in two years. When I unscrewed it, this is what came out.

zinccomparison

On the left is the two-year-old zinc. On the right is a new pencil zinc. This was bad. However, I didn’t have any seawater coming out of the hole, so I resorted to taking a selfie with the heat exchanger to see what was going on down there.

heatexchangerselfie

There was still zinc left in the hole. However, two or three pokes with a screwdriver, and that little bit of zinc left crumbled to pieces and fell right out. I then installed the new zinc and promised myself I’d start checking it every six months.

zincinexchanger

Once the new zinc was installed I opened the seacock and watched for leaks from the strainer lid as it filled. With no leaks from the strainer, I cranked up the engine and looked for waterflow from the exhaust. Water was flowing, so I popped back into the cabin to check for leaks from both the raw water pump and then zinc.

Once I’d verified that my maintenance hadn’t caused any new problems, I moved on to my next project, which I’ll blog about tomorrow — installing a NMEA 2000 backbone.