Westerbeke Weirdness

fwebster

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TECHNICAL Contributor
Oct 6, 2006
12,150
Middle Tennessee ; Panama City Beach, FL
Boat Info
1996 450DA
Engines
3116 Caterpillars
I have a Westerbeke 8BTD generator that has run flawlessly for a lot of years. It has required paying attention to the cooling water flow because it will run and cool itself well past the useful life of its impeller. Getting to the impeller is a real pain, so it is better to stay ahead of the maintenance clock and change it proactively rather then when it quits cooling. Well, last Fall I noticed the flow was less than it should have been, so I replaced the entire water pump (every other impeller change) and all was once again good in the Westerbeke world.

So here we are about 20 hours and 4 months later and the flow is down again. It still cools, starts and runs fine, but not nearly as much flow as usual. It has been about 5 years since I cleaned the heat exchanger, so I figured I'd pull the end caps and see what it looked like. I was hoping to avoid losing my coolant by removing the heat exchanger from the boat to acid clean it......the over flow bottle had nice pretty green coolant in it so I was hoping. The tube bundle was iffy, so I proceeded to take the heat exchanger off the boat to give it an acid bath. When I drained the antifreeze it could not have looked worse. Rusty, dirty, smelly and full of crud. The heat exchanger had parts of the hose reinforcement that had rusted into pieces in it. Even though the expansion bottle was clean, the cooling jacket on the engine was definitely not.

We pressure tested the heat exchanger and it tested ok, but it was about 65˚, not up to operating temperature. We could get a bucket of water up to about 140˚ so we heated the heat exchanger then pressure tested it again. Low and behold we got bubbles in the cooling side with 10psi of pressure. All I can figure is that the heat exchanger acted like a radiator cap and allowed the pressure and coolant to escape thru a small leak when it got up to room temperature only to have it draw sea water back in as it cooled down, thus acting like an expansion tank only opening at a lower temperature than the radiator cap releases at.

We are going to replace the heat exchanger since we found an aftermarket source on a replacement exactly like the Westerbeke OEM one. I am going to flush the cooling side with Salt-Away then flush it with a radiator cleaner before buttoning it back up with new coolant in the system.

Lessons learned here are don't just look at the coolant in the expansion bottle.......take the radiator cap off and look down in the expansion tank. Also, this happened to be on my generator, but it could happen to any engine with a closed cooling system.
 
Thanks for the heads up Frank. This is an item I would not have considered. Can you share the replacement heat exchanger source?
 
I bought it thru my marina parts department direct from the manufacturer, whom we think is where Westerbeke gets them. The Westerbeke OEM replacement was $890......this one cost $460. If you need one, I'll put you in touch with the parts guy at the marina.
 
Frank,

Is there such thing as Westerbeke recommended HE service (similar to what Cummins recommends every 5 years)? Obviously, my gen is made by Onan, but in "Cummins world" we follow the same scheduled interval.
 
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