Yanmar engine water pump

[Halo]

Did my routine engine check yesterday and found coolant tank nearly empty. Traced the leak to water pump which drips when engine warm. This is second pump failure in 3 years. Does anyone know an equivalent to a 3YM30 engine water pump? Has anyone else suffered the same?
All the best
Martin

 

[RichardS]

If you are using the correct 50% long life coolant mixture and the fan belt is not too tight and the engine is not running too hot it sounds like bad luck I'm afraid.

I've had no issues with either of my 3YM30 coolant pumps over 7 years but have had water pumps on cars which have lasted 30,000 miles and 120,000 miles for no discernable reason.

Richard

 

[FullCircle]

A known problem with 3YM30 pumps I am afraid.The answer is to have a hardened/plated spindle which Yanmar wouldn't cough up for with Johnson pumps.

However, I rebuilt mine using parts from Aquafax, much cheaper than a Yanmar pump. Also mine has now gone 700 hours which is better than the 300 for the first one. DO heed the 'not too tight' belt advice though.

Here are the prices from 2010

3YM30 part numbers & prices from Aquafax Luton

Impeller & Cover gasket 09-810B-1 £20.51

Bearing Front 05-08-124 £6.28

Bearing Rear 05-08-130 £9.80

Seal 05-29-139 £3.59 2 required

Shaft 01-46541 £38.00

all plus VAT

 

[Tranona]

Did my routine engine check yesterday and found coolant tank nearly empty. Traced the leak to water pump which drips when engine warm. This is second pump failure in 3 years. Does anyone know an equivalent to a 3YM30 engine water pump? Has anyone else suffered the same?
All the best
Martin

Are you talking about the seawater pump or the one in the engine for the fresh water coolant? Leaking seawater pump would not necessarily result in loss of coolant unless the engine overheated badly.

 

[RichardS]

A known problem with 3YM30 pumps I am afraid.The answer is to have a hardened/plated spindle which Yanmar wouldn't cough up for with Johnson pumps.

However, I rebuilt mine using parts from Aquafax, much cheaper than a Yanmar pump. Also mine has now gone 700 hours which is better than the 300 for the first one. DO heed the 'not too tight' belt advice though.

Here are the prices from 2010

3YM30 part numbers & prices from Aquafax Luton

Impeller & Cover gasket 09-810B-1 £20.51

Bearing Front 05-08-124 £6.28

Bearing Rear 05-08-130 £9.80

Seal 05-29-139 £3.59 2 required

Shaft 01-46541 £38.00

all plus VAT

In my response I've assumed that we're talking about the centrifugal coolant water/antifreeze pump otherwise why would the coolant have gone?

I think you're referring to the seawater cooling pump which is self-priming (although not always!) and works on a different principle.

Richard

 

[FullCircle]

In my response I've assumed that we're talking about the centrifugal coolant water/antifreeze pump otherwise why would the coolant have gone?

I think you're referring to the seawater cooling pump which is self-priming (although not always!) and works on a different principle.

Richard

Yes Richard, you are correct, this is the seawater pump.

No problems to date with the coolant except for a leaking rad cap.

 

[jwilson]

Yes Richard, you are correct, this is the seawater pump.

No problems to date with the coolant except for a leaking rad cap.

My local Yanmar agent says "nice engine but #%*# Johnson pump"

 

[Halo]

Many thanks for the replies to date. I can confirn that it is the coolant pump and NOT the seawater pump that has failed. The belt tension is about right at 1/2" play and no overheating I am aware of to date. All further thoughts re equivalent pump would be appreciated.
Martin

 

[FullCircle]

My local Yanmar agent says "nice engine but #%*# Johnson pump"

Unfair to Johnson. Yanmar specified the cheapest possible options......