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thron 04-30-2013 12:08 PM

Westerbeke 12B Two Coolant Flush/Replacement

I was wondering if anyone had any pointers for replacing the coolant in my Westerbeke 12B Two.

I currently have the old green coolant that is starting to look not so fresh. I don't have any history behind when it was last replaced. I'd like to go to a long life coolant but I don't know exactly how to go about that. The manual is lacking as to where the drain plugs are to eliminate the old coolant.

I should mention that I also have a water heater so the coolant does circulate through it.

Any pointers would be greatly appreciated.



liquidus 05-08-2013 09:51 PM

Re: Westerbeke 12B Two Coolant Flush/Replacement
I also have a Westerbeke 12B-Two and am about to do a flush for the first time... I would love to hear some pointers from anyone with experience with this engine.

W, Since it sounds like you may be a bit newer to this engine than me you might like to know that it is actually a "marinized" version of a Mitsubishi K2AS Diesel Tractor engine. If you look up the manual for the K2AS you will see that Westerbeke copied some of the pages right out of the original Mitsubishi manual. This is useful knowledge because it can help you find cross-referenced parts for the diesel tractor engine at a fraction of the cost that Westerbeke sells them.

Things like the raw-water heat exchanger, water cooled exhaust, and the extra pulleys to run the raw water pump are the marinized parts that Westerbeke added.

Here's my list of commonly replaced parts with cross-references to commonly available parts. If anyone else has anything to add to this list please share the knowledge!

Engine Oil: 10W30 Marine grade, Diesel Grade, 3.3 quarts

Oil FIlter: Napa Gold 1334 or FRAM - PH3593A or similar cross reference

Westerbeke Water Pump: 46120
Westerbeke Replacement Impeller: 46622 (OEM kit) , Globe 1112 (aftermarket run-dry impeller avail from Defender)
Also found a reference to a "volvo-penta-3586501-R13" fitting the 12B-Two raw water pump

Replacement Alternator: Advance Auto Parts Part No. 186-0486 which is an alternator for a 1983 "Mitsubishi Cordia" Cost $65 compared to $400+ from Westerbeke

Hope this helps!


tatracy 08-25-2013 10:39 AM

Westerbeke 12B Two Coolant Flush/Replacement

I have same setup, thanks so much for the info here. Wondering if you Havedetails on gearbox fluid change. I have the manual, but it does not specify if fluid level should be checked with engine running or stopped. Any thoughts on this?

liquidus 09-05-2013 09:04 PM

Re: Westerbeke 12B Two Coolant Flush/Replacement
Assuming you have the original Hurth transmission you should check the fluid level with the engine off. Don't screw the dipstick back in when checking your fluid level either... Unscrew it, wipe it clean, then reinsert until it stops at the threads but don't screw it down, then pull it back out and look at the level. I always checked mine when the transmission was cool. It is usually suggested to replace your fluid once a year or every 250 hours of use.

If you poke around on the Westerbeke website long enough you should be able to find the technical manual for this engine. It has lots of extra information including info on the transmission.

Incidentally, I ended up replacing the Hurth HBW-10 transmission that was originally on my Westerbeke with a Twin-Disc TMC-40P 2 seasons ago. So far it has worked very well with about 250 hours on it and no problems at all.

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