Yanmar Antifreeze Pump Bearing Problem

[arcadiahunter28]

I bought my 1990 Hunter 28 ten years ago last month, and during that time I never had hot water that came from the heat of the engine because the valve next to the heater had meet turned off. I opened it and of course it started leaking so I replaced it and I now have hot water.

That was two weeks ago. All of a sudden yesterday I heard a strange noise from the engine just as I was docking. Sounded like grinding. After doing some investigation, changing the belts, the oil, and the oil filter I ran it today and it still just didn't sound right. I found the problem: turns out the antifreeze pump wheel is REALLY loose, so much so that antifreeze is steadily leaking out when I wiggle the wheel.

Yanmar Antifreeze Pump

youtube.com

It's a Yanmar 2GM20F. Looks like I need to replace the pump. I found some info from an older post, looks like I can buy a new one and replace it.

Amazon.com

Has anybody run into this issue?

- Mark

 

[Tally Ho]

Yeah, it looks like the bearings are shot, and who knows what else.

You can probably rebuild it if you are mechanically inclined…or just purchase on.

I have a 2GM20F in my 1988 O’Day 322. I haven’t had any issues with my fresh water pump. I am in fresh water (Lake Michigan).

Greg

 

[arcadiahunter28]

Yeah, it looks like the bearings are shot, and who knows what else.

You can probably rebuild it if you are mechanically inclined…or just purchase on.

I have a 2GM20F in my 1988 O’Day 322. I haven’t had any issues with my fresh water pump. I am in fresh water (Lake Michigan).

Greg

I'm on Lake Winnebago, High Cliff State Park

 

[arcadiahunter28]

New pump is installed, and I’m about to flush and refill the coolant. There’s an in-line vent on the highest part of the hose - does that automatically bleed air or do I have to open it while the engine is running and then close it when fluid leaks out?

 

[jviss]

I'm not a Yanmar guy, but that looks like a regular petcock, and used to bleed. I like to pump coolant in through the block bleed at the bottom of the engine, have found that method fool proof, and not requiring fussing with "burping," bleeding while running, etc. But, you need a block drain petcock with a hose barb on it. My Universal M25 had just that.

 

[jviss]

By the way, you might want to rebuild the old pump and hang on to it. I'm sure those are not cheap for Yanmar.

 

[BigEasy]

I'm not a Yanmar guy, but that looks like a regular petcock, and used to bleed. I like to pump coolant in through the block bleed at the bottom of the engine, have found that method fool proof, and not requiring fussing with "burping," bleeding while running

Yes, that is a manual petcock; have to open it to bleed any residual air in the system. On my Yanmar 3YM30, there is a Schrader type fitting that can be used for bleeding air. I like to use same method as @jviss. Pump the coolant mixture through the entire system, including water heater, to prevent air lock, overheating, and minimal bleeding , if any.

PS: Those are generic orange colored electrical wire nuts as seen in your photo. Crimp type connectors are indicated for that application.

 

[kappykaplan]

PS: Those are generic orange colored electrical wire nuts as seen in your photo. Crimp type connectors are indicated for that application.

Just to pile on, wire nuts have no place on a boat.

 

[jviss]

wire nuts have no place on a boat.

Sounds like a good title for a new thread.

 

[BigEasy]

New pump is installed, and I’m about to flush and refill the coolant.

Hate to bring this up; however, those hoses appear to be the original hoses that were installed during building the boat. They are now over 30 years old and over due for replacement. I would not only replace the hoses but also clean out the heat exchanger & replace the thermostat & raw water impeller. Then you should have a trouble free cooling system for the foreseeable future. Sorry, know that you probably didn't want to hear that!

 

[arcadiahunter28]

I just put a new impeller in two weeks ago. And you’re right about the hoses. And the wire nuts.

 

[Ken13559]

I bought my 2GM20F cheapo FCW Pump from AliExpress (3rd party). Fit it in and it works great. Tried to service the leaky ones and finally gave up as its too much trouble.