Yanmar Water Pump Leak

[tahoebyrne]

I am cruising down the ICW on my Lagoon catamaran. One of the engines has been leaking a small amount of antifreeze. Today the antifreeze (greenish) appears to be mixed with oil and specks of metal. When the engine developed a strange intermittent squeal I cooled it down and shut it down. The oil appears to be coming from the freshwater pump behind the pulley. The antifreeze also appears to originate from there although I can't see behind the pulley. My question is what is the most likely cause of the problem and any suggestions for repairing it. I am trying to arrange a mechanic in Brunswick Georgia to do the work.

[tahoebyrne]

After reading a previous thread I used a mirror and a flashlight to look behind the water pump pulley and there was a 1/4 inch hole with oil and/or grease coming out of it. It appears that the antifreeze is also coming from there. Does the presence of oil or grease indicate a more serious problem? The amount of antifreeze that drips is about 1 ounce per 6 hours of operation. Although today fluid appeared after only 30 minutes of use. Do you think it will be safe to run the engine?

[sailorchic34]

Odds are the pump seals have reached that point when they don't....seal. So either a rebuild (bearings and seals $) or replacement ($$$) would be the next step. Odds are the other engine's water pump is getting close to R&R time too.

[TacomaSailor]

Yanmar designed the seal on the shaft to dribble a little and leak more and more as it wears out. I went thru your experience several years ago on my Yanmar 4JH2E at 2,750 hours. I ignored the leak for about 50 engine hours and it kept getting worse.

I installed a new water pump and the leak stopped.

More research, after installing the new pump, revealed that many reciprocating engine water pumps have this designed in "weep hole" feature to provide the owner/operator plenty of early warning that the water pump needs replacement.

Google "diesel engine weep hole" and find thousands of references - here is a good one

https://www.flowkoolerwaterpumps.com..._failures.html

[Lepke]

Most likely, the water pump bearing is failing. As the bearing gets worse, it effects the seal because the shaft no longer runs true. Shortly the seal will fail and much more coolant will flow.
As long as the engine has coolant and the pump can circulate it, the engine should survive, but the pump should be changed asap.
If the pump is rebuildable, the longer it is run, the more it is damaged. Eventually it will be un-rebuildable. First the bearing, then the seal is damaged. In a short time the shaft and housing will be damaged.

[boatbod]

First the seal on the coolant side of the pump failed enough to start weeping, then the shaft rusted a bit and wore out the seal on the block side of the pump. Now the pump is leaking both coolant and oil and it's only going to get worse. Soon the bearings will fail due to water ingress. Do yourself a favor and get a new pump installed asap.

[01kiwijohn]

Almost all pumps have weep holes. Leakage indicates that the bearings are worn, so the shaft isn't running true, causing the sealing faces to allow leakage.
It will fail soon, only a question of when.
When you replace or repair, do not run the belt tighter than specified. The

[a64pilot]

Darn, your all right.
I doubt it's oil though, more likely worn out metal mixed with antifreeze that is slippery, there should be no oil near the fresh water pump.
Easy fix, although I'd flush the coolant too while your there and half of it is drained anyway, but then I'd clean the heat exchanger, just cause too.
So far as running it, I wouldn't or I'd wait until docking or another maneuver required both engines, then I'd run it. I'd hate to be running it when I didn't need it and the pump go out completely and then not have it for docking.

Might even consider servicing the cooling system on the other engine as they are likely the same age, same service interval etc.

[tahoebyrne]

Thanks to everyone who replied, I appreciate the information. I have ordered a new water pump and will pick it up in Fernandina and install it asap. All the boatyards and marinas are booked up because of Hurricane Matthew so I will be doing the install myself. The heat exchangers have recently been overhauled so I will just drain and replace the coolant when installing the pump. I bought a service manual online which should help. Any other tips than don't overtighten the belt?

[jhulmer]

I agree, seals failing "permanent" lubed bearings leaking account for the oil mixed with coolant and the squeal you heard is the bearings starting to seize. replace asap.
I've had it happen to me, tried to rebuild the pump but the vanes had cut into the aluminum body rendering it s....crap.
Jim

[a64pilot]

Water pump is easy, but you may be threading bolts into aluminum so don't overtighten. I'd get some antiseize for the bolts. I use grease for the gasket, no leaks and easy removal later. If you feel the need to glue the gasket on only do so to the pump as that way one day you wont be scraping glue off of the engine side.

[MikeTC]

I have been advised to use Yanmar coolant...correct PH etc. Hope it all goes well for you.

[boatbod]

Originally Posted by MikeTC

I have been advised to use Yanmar coolant...correct PH etc. Hope it all goes well for you.

Any DexCool (orange, extended life) antifreeze it's ok in a Yanmar.

[a64pilot]

I have always had good luck with Dexcool, but not everyone has, if you don't maintain your cooling system as in preventing any air into the system, Dexcool can become a nightmare.
Never, ever mix anything with Dexcool except water. I don't know the chemistry, but its not compatible with other forms of coolant and mixing apparently leads to sludge and blocked cooling systems.
Dexcool was intended to be a long life coolant, and I think it is, but as has been pointed out here by I think Ranger42 the likely hood of salt water contamination of your coolant is high, that along with your likely to be cleaning your heat exchanger more often then every five years, makes a long life coolant not what you want on a boat.
I would do a very, very through flush and just use plan ole Prestone and plan on changing it ever couple of years when you clean your heat exchanger.
I installed the Prestone flush kit into my water heater hose and flushed it just like a car, cause it is just like a car.

Google Dexcool problems

[boatbod]

Over the years I've seen many different types of coolant contamination and resulting problems. None are immune to neglect...

That said, use the manufacturer recommended coolant and service intervals and your problems will be minimized.