Volvo Impeller thrown a blade, should I be worried?

[Skylark]

Getting ready for launch, I've today changed the impeller on my Volvo MD2030. After removing the pump cover, to my surprise the old one, fitted about this time last year, has one of its rubber blades missing. First time in my experience I've seen this. I removed the up-stream vertical hose, about 2 ft long, but it was clear. I didn't continue the search for the missing blade.

Should I be worried that it may now be lodged / stuck in a water gallery waiting to give me a problem? Or should I ignore it?

Many thanks for your views.

 

[Norman_E]

If your engine has indirect cooling it has probably lodged in the heat exchanger, but whether it is worth trying to find and remove it is another matter. Most likely it will not do any harm on its own, but check that you have undimished flow of water from the exhaust when the engine is running.

In a direct seawater cooled engine I would be worried as it could block a water passage in the cylinder head or block leading to localised overheating.

 

[sailorman]

Getting ready for launch, I've today changed the impeller on my Volvo MD2030. After removing the pump cover, to my surprise the old one, fitted about this time last year, has one of its rubber blades missing. First time in my experience I've seen this. I removed the up-stream vertical hose, about 2 ft long, but it was clear. I didn't continue the search for the missing blade.

Should I be worried that it may now be lodged / stuck in a water gallery waiting to give me a problem? Or should I ignore it?

Many thanks for your views.

One has to ask why was it still in the pump during lay-up

 

[chuzzlewit]

Surely no harm in leaving it in place if you

were going to discard it before next season?

 

[VicS]

One has to ask why was it still in the pump during lay-up

For the same reason that 99.9% of them are I expect. People dont take them out.

Likewise impellers in outboards who takes them out?

 

[tillergirl]

If its broken off as one piece it will be too big to enter any of the heat exchanger tubes and therefore will be found if you take off the end rubber cap at the front of the engine. Removing the tube stack is pretty easy anyway, slacken the two jubilee clips and remove the front rubber cap, slacken off the smaller jubilee clip at the back of the heat exchanger and probably you will be able to slide the tube stack out at the front leaving the rear end cap in position. If you not how far the tube stack protrudes at the front, you just replace it to this position taking care to ensure that the top of the tube stack is on top (there are some holes at the bottom). The manual says the tube stack is marked 'top' but mine isn't; it just has a small hole on the top to indicate the top. It's quite easy.

 

[peterc(not the footballer]

I have had this happen several times with my 2030. I replace my impellor every year, so I do question the quality of the impellors. It has not caused a problem for me - the bits turn up in the heat exchanger when you clean these out: a worthwhile job, and not difficult.

Peter

 

[john_morris_uk]

If its broken off as one piece it will be too big to enter any of the heat exchanger tubes and therefore will be found if you take off the end rubber cap at the front of the engine. Removing the tube stack is pretty easy anyway, slacken the two jubilee clips and remove the front rubber cap, slacken off the smaller jubilee clip at the back of the heat exchanger and probably you will be able to slide the tube stack out at the front leaving the rear end cap in position. If you not how far the tube stack protrudes at the front, you just replace it to this position taking care to ensure that the top of the tube stack is on top (there are some holes at the bottom). The manual says the tube stack is marked 'top' but mine isn't; it just has a small hole on the top to indicate the top. It's quite easy.

The small hole in the top is to make sure that it fills with water/coolant properly hence it has to be at the top. Mine doesn't have 'top' stamped on it either.

You almost certainly don't need to remove the stack; I will put money on you finding the impeller blade at the front end of the stack. Just take off the rubber end cap (three jubilee clips and a bit of levering) and it will be there before your eyes, or I will eat my proverbial hat.

 

[TonyS]

My experience was that it is either stuck in the pump outlet, but I think you have checked that. Secondly it will be at the front of the heat exchanger as others have indicated. However, you dont need to take anything off except the rubber pipe from the anti syphon. You can then put your finger in to the front of the heat exchanger and will feel it. A small pair of long nosed pliers inserted the same way will easily remove it.

Your main concern should be as to why it failed. The answer is that your pump has run dry and probably repeatedly. I used to have your problem and some impellers only lasted 3 months. Then I found that if you keep water in the pump, there is no longer a problem and the impeller lasts it's designed life of several thousand hours! The water pump seal also lasts very much longer.

 

[Monique]

You were lucky; normally, failure of one blade causes a complete blade departure by all its bros and sisters. They wear out.

GL

 

[Skylark]

Many thanks for the helpful comments.

I'll remove the end cap and search in front of the heat exchanger. I hope it's there because I wouldn't want to give you, John, indigestion after having eaten your proverbial hat.

I'm more intrigued with your comments, Tony. It's always good practice to establish the root cause of any failure and to take steps to ensure a non reoccurrence. I have a Beneteau Ocean 361 and I've not changed my routines. I always check for water flow immediately after starting. At the end of a season, I run a bucket of water/antifreeze mix through to clear away salt. It may have run dry but I've done this for several years without previously encountering a problem. How can I "keep water in the pump"? As always, the newly fitted impeller is generously coated with vaseline.

 

[davidfox]

Should I be worried that it may now be lodged / stuck in a water gallery waiting to give me a problem? Or should I ignore it?

Many thanks for your views.

I had a bad patch where i had to replace 2 in one year (forgot to open seacock etc) the people who service my engine said they would find and remove any bits,
so i thought no more about it. I was up the top of the ijselmeer about to do something tricky under engine, when all of a sudden the overheating alarm went off and headless chickens ran everywhere, when i eventually I got to somewhere safe, I called an engineer who took off the cover to the oil cooler and pulled out a small handful of mangled blades which had blocked the water flow, far more than i had been responsible for, previous owner had presumably done the same. Running at a temperature higher than normal is a warning sign, also the oil pressure registered slightly lower (increased temp?) all above noted in retrospect.

 

[tillergirl]

Many thanks for the helpful comments.

I'll remove the end cap and search in front of the heat exchanger. I hope it's there because I wouldn't want to give you, John, indigestion after having eaten your proverbial hat.

I'm more intrigued with your comments, Tony. It's always good practice to establish the root cause of any failure and to take steps to ensure a non reoccurrence. I have a Beneteau Ocean 361 and I've not changed my routines. I always check for water flow immediately after starting. At the end of a season, I run a bucket of water/antifreeze mix through to clear away salt. It may have run dry but I've done this for several years without previously encountering a problem. How can I "keep water in the pump"? As always, the newly fitted impeller is generously coated with vaseline.

David, don't beat yourself up over it. I have religiously replaced the impeller on my 2030 for 15 years. I have 14 perfect used impellers as spares. One failed in 15 years with the v near loss of one blade (hadn't quite come off). There was no obvious reason for it happening and it hasn't happened again. Even when I have had water inlet blockage - 4 times with weed blocking the inlet and once with a Jelly Fish, the impellers survived. Just occasionally one goes. It's fate.

 

[TonyS]

Many thanks for the helpful comments.

I'll remove the end cap and search in front of the heat exchanger. I hope it's there because I wouldn't want to give you, John, indigestion after having eaten your proverbial hat.

I'm more intrigued with your comments, Tony. It's always good practice to establish the root cause of any failure and to take steps to ensure a non reoccurrence. I have a Beneteau Ocean 361 and I've not changed my routines. I always check for water flow immediately after starting. At the end of a season, I run a bucket of water/antifreeze mix through to clear away salt. It may have run dry but I've done this for several years without previously encountering a problem. How can I "keep water in the pump"? As always, the newly fitted impeller is generously coated with vaseline.

I have a saildrive, and they are worse. I can see through the transparent hoses that the water level drops through the pump as air is allowed in from the anti syphon valve. This is worse when sailing fast. VP say the pump is self priming, so don't care. However the short time before water is drawn in again is when it is dry. The solution is, above the pump and before the anti syphon valve, fit a non return valve. It has worked for me and costs less than £10.

And I wouldn't remove the end cap as that will cause problems with sealing and buying new clips etc.

 

[Vara]

the newly fitted impeller is generously coated with vaseline.

I thought that vaseline was a no/no, and glycerine was the correct lubricant to use.