This info applies to at least the latest V8-380/430 and any other Volvo Penta using impeller part number 2170045.
First, on some boats, the impeller can easily be changed in the water. On others, when you remove the plate off the face of the seawater pump or a pump hose, water will continue to flow into the boat. I learned the hard way that the R5 is in the latter category. You can still do the change in the water if you are brave or must - the bilge pump easily can out-pump the flow of water into the boat, but a much better idea to do it on land. Seating the intentionally slightly oversized O-ring with water rushing by can be tricky, and it is just more risky stressful overall. If you are brave, changing in the water has the advantage of allowing easy testing as soon as you are done.
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What you will need:
- 8mm socket
- VP impeller kit 21700445 (DO NOT buy the non OEM/VP copy - it is not threaded and will be very difficult to remove!) Don't just get the impeller itself either. The new o-ring is a MUST, and its nice to have the new sets of bolts, lock washers and o-rings.
- A tool to pull the impeller. This impeller is really tight in the housing. The housing metal is soft, and scoring it with a screwdriver or needle-nose will impair the function of the pump. I got the plastic Sherwood 25105 (look on ebay - $19 delivered). I also ordered a metal bolt 3/4"-16 thread, but the Sherwood is well made, threads in the impeller nicely, and provides a convenient grip for removal. Mark (mdadgar) has ordered the VP part (I cant find it) which is a bolt inside a bolt. This might be even better - we'll see.
- Glycerin - don't skimp here. Get Glycerin. CVS sells it here. Volvo used to include a small tube but stopped. You will want to lube the new impeller so it doesn't get damaged when it briefly runs dry after the change. Do not use anything like Vaseline as it eats away rubber.
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Time to change the impeller...
- You're out of the water, time to remove the old impeller. Use the 8mm socket to loosen each of the 4 bolts until the housing face can come loose. Dont pull the bolts out - just get them out of the thread - there are small o-rings on each that hold the bolt to the housing face. Avoids bolts, washers, etc dropping into the bilge too. Note how "loose" the bolts are! When re-installing you must not over-tighten or you will ruin the pump. Remove the pump housing face.
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. . - Remove the single large o-ring. It probably is still sitting in the pump, but can fall out into the bilge. Put it somewhere you wont confuse with the new o-ring.
- Now thread whatever you are using to pull the impeller into the center of the impeller. If there aren't threads, the last change was done with a non OEM part, or it was installed backwards. In this case, you have no choice but to try a couple needle-nose pliers to work it out, but take care not to scratch the inside of the pump.
- As gently as possible, work the old impeller out of the pump. It will take some force. I found that the puller I had alone was not adequate. Some light tapping on either side of the handle with a ratchet made it easy to work out. You can also see that simply threading in the puller as far as it would go caused the impeller to push out. The "bolt in a bolt" puller is likely to be a better solution. Could also insert a bolt or plastic "shim" before threading in the puller.
- Lube the new impeller liberally with glycerin. Insert into pump. Don't worry about the direction of the vanes - they will self correct once the motor is running.
When it inserting the new impeller, it is critical to insert with the threaded side facing out to make subsequent removal easier. Perhaps use the puller as a pusher to be sure.... - Remove the old bolts, lock washers, o-rings from the housing face, and install the new ones - bolt and lock washer on the outside, o-ring on the inside.
- Put the new o-ring into the groove on the pump. You may notice the old one seems to fit nicely, and the new one seems too big. You must use the new o-ring. I didn't (because my first try I couldn't pull the impeller), and after reassembling it would leak badly. Since it is a little large, do your best to center on the groove.
- Push the housing cover in place and hold in the center to keep the o-ring in position. Tighten bolts (I used alternating/progressive tightening)- DO NOT OVER-TIGHTEN! I don't know the torque, but it isn't much.
- Once in the water, it is imperative to test, observe, and be able to have the boat out of the water if you have a leak. If there is a leak, and you used a new o-ring, it is most likely the o-ring out of the groove - don't just tighten the bolts - the housing metal is easily stripped.
- Once the engine is operating, Closely monitor engine temps - at least more intensely for the next hour of operation. Brand new impellers have been known to fail!
Hope this helps. A bit verbose, but figured better to help anyone that hasn't done stuff like this. Please add any other tips/corrections!
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Impeller tool 25105:
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