gdrosen":3bxdivkg said:
I am referring to the salt water pump not the impeller.
This is from previous post. This is inspecting the pump rather than replacing the pump. Volvo uses recommendations based on different conditions of use. They also know that the average boater is not going to inspect the pump tp see if it needs to be replaced. The average marine technician is not either. Volvo recommendation is to just replace it. Volvo says Buy our parts and pay our service technicians to install it and you will have a dependable raw water system. A good DIY boat owner can also inspect the pump for wear, seal failure and bearing failure. At each impeller change. The DIY owner knows the conditions that the boat and equipment has been operated in.
Was the pump ever run dry? Has the boat been grounded and powered off ? Has the boat been moored in a shallow yacht basin where silt, sand and mud have been stirred up and pumped through the raw water system? Is the boat used 100% in Salt water?
Water conditions with silt can damage wear surfaces, mechanical seals surfaces can be damaged from dirty water, The seal uses the raw water pumped to keep the seal area flushed so the seal faces do not get damaged. Dirty water can damage pump seals. Proper belt tension and belt care, pump pulley inspection and inspecting and replacing the impeller also helps keep the pump busy and components in good working order.
The servicing technician familiar with your boating conditions knows to inspect pump components when replacing the impeller. At this time he /she should advise replacement of the pump or rebuilding the pump. The service centers do not rebuild any more. Their labor is to replace. Many technicians will damage the pump rebuilding it. (lack of knowledge and experience.) Service managers don't want the liability of rebuilding. They would rather swap the pump out with new and use the manufactures warranty to pay for technician quality issues. This is the reality of service work today.
This is not to say that there are not good technicians out there. If you know a good one, support him/her and follow their recommendations. They know the area and the common failures associated with the way a boat is operated in the area.
Volvo makes recommendations based on worst case! My opinion is they are slack at some maintenance items and over the top on others. They sell parts and sell engines. Parts sales is a money maker. Reliable engines is marketing. Keep new parts installed reliability increases. There is a cost for that type of reliability!!
The Raw water pump in a Volvo is made by a pump company. Not Volvo! There are several engine manufacture that use the same pump. I have a Johnson pump in a Yanmar. Yanmar's recommendation for impeller replacement is 1000 hours or 4 years . Pump inspection is 2000 hours (wear) No years associated with pump wear. The pump is the same as Volvo's but the recommendations are completely different. Yanmar recommends at 2000 hours rebuild the pump and all raw water components ,Exchanger, after cooler and oil cooler.
Your question is "should I replace the pump or pump components at 4 years with 550 hours because that is what Volvo Recommends?" Use your knowledge of how you operate the boat. Remove the impeller and inspect the pump.
When I do my yearly impeller replacement. I may only have 150 hours since last replacement. I still remove the impeller and why put an old impeller back in? I put a new one in. Before installing the impeller I get my mirror out with a flash light and do a full wear inspection of the wear plates . I grab the shaft and feel for play deflection -Up/down/side to side play. If the belt is removed I would rotate the pulley and feel for a smooth rotation. Look for any signs of pump leakage. You will see if it leaked. If I have 700 hours on the pump and the engine has been in service for 6 years and all inspections proofed this pump to be in good working order. I'm putting a impeller in and I am confident that I will have smooth sailing.