Replacing the Freshwater Pump on aYanmar 3YM30

[Dan_Y]

Noticed drops of engine coolant forming at the water pump shaft on our 3Ym30. Only 750 hours on it and have been careful to not over tighten the belt. Seems fairly straightforward to change the pump. Anyone here done this and have any pointers or tips?
Thanks,
Dan

 

[NYSail]

Had my water pump go on my 3HM35f while out cruising years ago and had to change while in Newport. Pretty straight forward......

Good luck!
Greg

 

[seadaddler]

Are you sure it’s the pump and are we talking about the internal pump.
Nick

 

[Dan_Y]

Thanks Greg. Good to know.
Nick- yes is the internal coolant pump, like the water pump in a car.
The fresh water coolant pump impeller shaft is dripping antifreeze now. I wrapped the shaft with a paper towel and that’s where it leaks. Nothing coming out of the gooseneck, hose clamps, or hot water heat exchange plumbing. I’m getting a price from the Yanmar dealer. Around $350 I think. Have read they are very difficult to replace the shaft seals and it’s better off to just replace the pump as a unit.
Dan

 

[seadaddler]

I be interested on how the replacing of that pump and if possible take photo’s and post them here.
I do have 3YM30 in my 2007 H-36 and good to know how it’s done
but hope I won’t need the info.
Nick

 

[Jerry Clark H356 SV Persi]

I’ve got a pump for my 3GM30F but haven’t changed it yet because I have decided I should change the hoses at the same time. Have a similar small leak. Anyone bought new hoses for the 3GM30F water pump and how much are they?

 

[NYSail]

And one other thing with mine all I needed was the pump I did not need the housing. But check the housing as when the pump is going it could damage the internal housing. When my pump was going I heard the whining from The bearings. Take this time also to replace your hoses and flush the system completely and put in some nice new anti-freeze

Greg

 

[Dan_Y]

Good points Greg. I’ll be sure to take some photos and post back to this thread Nick.
I have the parts book and shop manual so that should help. I don’t expect to get to it until early March. I’m currently doing a major bathroom renovation and the Admiral would have low tolerance for boat projects while the master bath doesn’t have a shower or commode...ha!

 

[Scott B]

@seadaddler I uploaded the Yanmar 3YM30 Service Manual to the General documents downloads.

https://sbo.sailboatowners.com/dl/downloads.php

 

[seadaddler]

Thanks Scott B.
Nick

 

[Dan_Y]

Update. The freshwater pump replacement went pretty easily. Made one error at first and didn’t order the copper washer gaskets for the banjo fitting that supplies water to the the hot water tank. They leaked until I replaced them. Will post photos soon.
Dan

 

[Ken13559]

You might want to consider swapping out the spring clip of the oil seal with rubber o-ring of suitable size. The spring clip will eventually rust away results in leak. I had that leaks annually until I did the swap.

KenY

 

[Dan_Y]

KenY, what clip are you referring to? Take a look at the parts breakdown in the attachment to my post below. I didn’t see anything that looks like what you describe.
Thanks
Dan

 

[Dan_Y]

Well, I decided to document the fresh water pump replacement for my ships log. Plus this way I won’t forget the details a week after it’s done in case someone asks me about it.
Dan

 

[BigEasy]

Dan,
Thanks for posting the water pump replacement procedure. Excellent documentation! I saved a copy for future reference.
So how many hours did it take to complete the repair?

 

[Dan_Y]

Thanks!

If you were only changing the pump (heat exchanger not removed), and the new pump was painted, it would take me about 5-6 hours. I’m pretty slow. “@#$&*...the tool I need is on the bench at home 45 min away”. Drain coolant, remove alternator belt, remove coolant radiator hoses, hot water heater hoses, remove gooseneck and thermostat, then swap the hot water fittings and temp sensor over to the new pump, and put it all back together. An hour is included talking to buddies on the dock.... Another 5-6 hours was needed to R&R the heat exchanger and clean/paint the engine and pump. Total it was a 10-12 hour job over a week/weekend.

I need to up date the document. The triangle looking gasket that seals the water pump to the engine must be ordered separately-it did not come with the pump. The O-ring did.
Dan

 

[Ken13559]

Dan_Y, sorry my mistake. I was referring to sea cooling water pump. Whereas yours is fresh water pump.

KenY

 

[Dan_Y]

Ohhhhhhh....no problem Ken.