Volve 5.7 w/ SX - Fuel Pump Whine?

[98LarsonGM57]

I've got a 98 Larson that I put a new crate vortec 5.7 in last season - it has 92 hours on it now. <br /><br />Anyway - I've been hearing a whinning noise come from the engine compartment for a while now - perhaps forever, but it is making me more and more paranoid as the days go by and now that I have the full cover on for winter it is really noticable at low speed/idle. At first I was thinking it was the alternator - but now I am shifting my thoughts to the fuel pump..<br /><br />It runs perfectly smooth and powerful, etc. Should I be worried? Will it just crap out one day or will it start running badly?<br /><br />Also is this an easy fix? I'm about out of money for the season so I don't want to visit the mechanic - but don't care to get stranded on a cold night either. <br /><br />Any advice / thoughts are greatly apprecieated. <br /><br />Lee

 

[tommays]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

that is the 64 million dollar question <br /><br />if there is a noise it is a warning that something is wrong and is asking to be fixed generaly speaking if a part is makeing noise it will fail at the worst possable time<br /><br />i can only recomend you try to find the real sorce of the noise i think you would have heard it before if it was always there<br /><br />tommays

 

[Dunaruna]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

Under bonnet noises can be difficult to locate, noise travels.<br /><br />Couple of easy things to try: Remove belts and run the motor for a few seconds (no longer), if the noise disappears you know its something that the belts spin (alt/water pump etc).<br /><br />Borrow or buy a mechanics stethoscope, put it on the fuel pump and surrounding areas, you'll know when you are close to the source of the noise - don't poke around anywhere near electrical contacts or spinning pulleys/belts.<br /><br />May even be a small vaccum leak.<br /><br />Aldo

 

[98LarsonGM57]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

I determined that the buzzing sound is coming from the black cylindrical device located above the fuel filter - I am going to go out on a wild guess here and assume it is a fuel pump - it has the number 5850810 on it.. I am assuming since I hear it over the engine growl with the cover down that it is a cry for help. Should I just replace it or start with the fuel filter and for as a novice is there anything else I need to buy/know - it seems pretty straightforward..<br /><br />Any advice is greatly apprecieated.

 

[tommays]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

98<br />it would be a good time to buy a service manual as you wont have to guess what the thing is<br /><br />if it is the fuel pump it has to be replaced with a marine rated pump and best if its the same one for easy swap<br /><br />tommays

 

[98LarsonGM57]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

It is the pump, looks like I need a 18-7330, I found one on boating solutions.com for $150.<br /><br />I hear ya on the manual but it looks like I can pull a cord and turn two screws to switch it out.

 

[98LarsonGM57]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

Do I have the wrong pump on my engine? I have a 350 vortec volvo and the parts lists are telling me I need part 18-7330 (boat is a 98, engine was bought in a crate last year) but the pump has the number 3850810 on it which corresponds to an 18-7331 which supposedly fits a 454 or a 502?? <br /><br />Any advice on what to replace it with?

 

[98LarsonGM57]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

Do I have the wrong pump on my engine? I have a 350 vortec volvo and the parts lists are telling me I need part 18-7330 (boat is a 98, engine was bought in a crate last year) but the pump has the number 3850810 on it which corresponds to an 18-7331 which supposedly fits a 454 or a 502?? <br /><br />Any advice on what to replace it with?

 

[Red Fuel]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

The whine you have discovered is the combination high and low pressure fuel pump system. I've encountered this particular scenario several times on volvo engines and seen no reason for it and no problems associated with it. I had one customer with 1200 hours have the noise go away and another who had it come up with 235 hours and we changed it immediately at his request. The procedure is simple if your doing it yourself, but if it's fuel injected you'll have to bleed the air out of the pump at the schrader valve (bicycle air valve at the bottom right hand side of the pump).

 

[98LarsonGM57]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

Thanks Red, I was going to change the filter (it is nearly a year old anyway - perhaps it is a little clogged and causing the pump to work harder) to see if it would help. But it sounds like your telling me that the noise is not necessarily an indication of anything alarming and that it could go on for many hours (ie. 100's)like this... <br /><br />This is a 98 boat - but I put a new crate 350 in it last year - so I assume the block is a 2002 or a 2003 as it was a new one and not a rebuild, but I believe it still has the fuel pump from the old motor on it and accordng to the book it should be and 18-7330; but cross checking the model number from my existing pump it is a 18-7331 which is supposedly for a 454/502...? <br /><br />Is this a problem?<br /><br />Thanks again for everyones assistance. <br /><br />Lee

 

[Don S]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

Don't go by the number on the pump. It isn't the pump number.<br />Assuming you have a carbed engine (mostly because you never mentioned having 2 pumps) the Volvo part number for the pump is 3858261. So you can convert to your sierra numbers from that one.<br />There are several different ones used by Volvo, and all look the same physically but have different pressures. Just make sure you have one that crosses to the Volvo number.<br />And yes the Volvo pumps whine. It's quite normal and no reason to replace the pump, because the new one will whine also.<br />If it does concern you, buy a new one and keep it as a spare. The pumps doen't go out very often, running dry is the usual cause of failure. That's why I always fill the fuel filter before installing.

 

[charleswmoore]

Re: Volve 5.7 w/ SX - Fuel Pump Whine?

Thought i would throw in my two cents. My volvo 5.7DP also uses a dual pump. This pump also whines.<br />It seems to change as the season goes on. Also I notice that when I feel it is the loudest I change fuel filter. Maybe twice a year. The filter is relatively small and very easily changed. Unless it is squealing I doupt i would be concerned. Also don't run it dry. Something else to consider is that <br />since you did a motor changeover mine is water cooled? Did you connect water lines to it? Ps I have almost 1400 hour on a 2001 so she definetly is used.