Raw water pump seal leaks and causes major damage 5.7gxi

[Fishtales22]

Hoping to get some feedback from other users. I have had two 5.7 gxi Volvo Penta engines in the past 6 years. The engine performs very well and the duo prop stern drive is awesome. The "package" has one serious problem. The raw water pump can leak salt water due to a failed seal behind the impeller housing. It has happened 4 times in the past 6 years. If not detected very early the leak can cause a catastrophic damage when the drip falls onto the serpentine belt and that creates a mist of salt water in the engine room. The mist is not detectable at idle. As the rpm is increased the amount of water dripping increases and the faster speed of the belt revolving creates the salt water mist.. The first time it happened in 2006 the engine was only 1 month old with 100 hours on it. We had gone 55 miles offshore fishing for albacore. On the ride home the seas were rough and the bilge light was going on and off as expected when taking spray from waves. The boat is a Skipjack 25 with a "wet bilge". The engine started losing power when we got near home port. When I arrived at home port I opened the engine box and saw something I had never seen before. The entire engine was coated in white salt crystals. The engine was ruined because it had inhaled salt water mist into the throttle body and all the external components were salt water damaged. The loss of power was from salt crystals blocking the flow of air into the throttle body. The salt got into the cylinder heads and eventually the engine was toast. Volvo Penta eventually replaced the engine but it wasn't easy. I detected a small leak 3 years ago on the replacement engine and had the raw water pump immediately replaced. 1.5 years later the engine running temp began to rise a small amount and soon after the raw water pump started to leak. I replaced that pump and cleaned the heat exchanger. The heat exchanger was clogged with debris mostly eel grass which is thick on one side of our harbor channel. I have avoided ever going outside the channel ever since. . The failed pump seal was possibly caused that time by the backpressure from the restricted flow in the heat exchanger. After cleaning the heat exchanger and replacing the raw water pump the temp returned to normal and the boat ran great. A month ago I noticed the engine had salt crystals on it after I took her for a two hour run. . Same pump seal failure. With the engine running at 700 rpm I slowly sprayed a mist of fresh water through the intake with a spray bottle in attempt to wash the salt through and then slowly dripped 1 quart of ATF through the intake. I replaced the raw water pump yesterday and while doing so discovered that the alternator bearings are ruined and so is the belt tensioner. I am hoping the cylinder heads are not ruined. Has anyone else ever seen this happen? It is strange that this has happened to my engine so many times and Volvo says they have never seen it before. Any suggestions would be greatly appreciated.

 

[Nickypoo]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

I've never experienced this specific situation before, but if it were me I would be making some sort of shield to deflect the leak from landing on the belts. A simple brass or stainless steel sheet metal shroud attached to a mounting bolt or two should suffice. Maybe you could also incorporate some zinc somewhere to help save your components.

If there is a hobby shop nearby you could check there for some brass sheet. Home Depot may have some stainless sheet metal, not sure on that.

I definitely think the raw water pump shouldn't be leaking so often. Perhaps it's a design flaw due to poor engineering by Volvo. On the other hand you could be creative with the problem just to save yourself the headache. Replace the pump seal and install a shield to prevent catastrophic damage if it happens again in the future.

 

[Fishtales22]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

I've never experienced this specific situation before, but if it were me I would be making some sort of shield to deflect the leak from landing on the belts. A simple brass or stainless steel sheet metal shroud attached to a mounting bolt or two should suffice. Maybe you could also incorporate some zinc somewhere to help save your components.

If there is a hobby shop nearby you could check there for some brass sheet. Home Depot may have some stainless sheet metal, not sure on that.

I definitely think the raw water pump shouldn't be leaking so often. Perhaps it's a design flaw due to poor engineering by Volvo. On the other hand you could be creative with the problem just to save yourself the headache. Replace the pump seal and install a shield to prevent catastrophic damage if it happens again in the future.

Thanks Nickypoo. I thought of doing that 5 years ago when this first happened. The is absolutely no room to do this.

 

[kmarine]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

These pumps are generally reliable. was your pump rebuilt or replaced. if only rebuilt there may have been a casting flaw resulting in eventual failure again. Is there an aftermarket pump available? That one might have better seals.

 

[Fishtales22]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

These pumps are generally reliable. was your pump rebuilt or replaced. if only rebuilt there may have been a casting flaw resulting in eventual failure again. Is there an aftermarket pump available? That one might have better seals.

4 brand new pumps since 2008!! Volvo certified from the dealer. Average life span 250 hours. Ridiculous in my opinion. If it was only the replacement of the pump I wouldn't be nearly as upset. The leak causes major engine damage.

 

[brucetruong]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

Wonder if there's a manufacturer that allows us to replace the whole unit,, to a more reliable and more parts accessible Seawater pump.

I have dual motors Volvo Penta ( 5.8Fi by FORD-only to realized that's built by FORD after I bought the boat, if I knew, I would not have bought it, even though it's a nice boat. ) It's a 1995 ,27' Chris Craft Concept,,both with bad Seals and Impellers and I'm having a hard time finding parts for them, Especially the Inner Seals for those pumps.

No offense for those Ford Lovers, but I have no confidence in them at all. And now I got 2 of them on a boat that I need to be reliable and parts are scarce for them too. I'm thinking of selling instead of dealing with these motors unless I can get parts for them.

Any advice would be greatly appreciated ( if you're offended, I apologize and no advice would be understandable )

 

[cptbill]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

is that a Sherwood pump? If so it's the same pump I've got on my 5.7gsi's I have replaced 1 pump in 10yrs. sounds like there is a problem with the casting as was said before or the mounting must be off a little any way the part # to fix the pump should be ( o-ring3858938, washer-827019, sealing ring-827427) easy to replace and bets spending big bucks on new pumps

 

[tpenfield]

Re: Raw water pump seal leaks and causes major damage 5.7gxi

This thread is 2 years old guys. . . . The forum rules frown on resurrecting old threads, unless the OP initiates it.

it may be better to start this discussion as a new thread :noidea: