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acv2rodzlc

Closed Cooling System

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My boat has a volvo penta engine with a closed cooling system. I took it for the 100 hours service and noticed a charge for impeller replacement. I know the engine does have an impeller even with a closed cooling system, but is it necessary to replace it?

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Yes it's cheap insurance.  Those rubber fins can go out at any time.  100 hours is a good time to change it.  If they gave you the old impeller back, keep it on the boat for a spare in case you need to do a field change.

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19 hours ago, acv2rodzlc said:

My boat has a volvo penta engine with a closed cooling system. I took it for the 100 hours service and noticed a charge for impeller replacement. I know the engine does have an impeller even with a closed cooling system, but is it necessary to replace it?

The raw water impeller is EPDM rubber, and they have both a service life and a shelf life and rule of thumb is 3 years or 300 hours, which ever comes first. The Volvo raw water pump sits right in front of the engine and is very easy to change so learn how to do it yourself as the part is cheap, and be sure to use a genuine OEM Volvo part, as there are a few inferior knock-offs out there. 10 minute job.  W

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1 hour ago, Toddler said:

Simple answer, is yes.

 

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Yes, remember that the sea water is running though the heat exchanger. Much like air going though your car radiator. So that impeller is pumping that sea water to the heat exchanger. With out that water, the engine will over heat. I too have a closed system, I change it out every 2 years to be on the safe side and carry a extra one on-board. Cheap insurance!    

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Concur!  Even with a closed system that impeller pushes the water through the pump to cool the engine.  I was 20 miles off shore and I started over-heating - come to find out one of my water pumps got sand it from the week before and it tore up my impeller.  Had to change it out on the water in order to get home.  Easy to do with Bravo Outdrives but I think with the Alpha outdrives the impeller is located inside the lower unit. 

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8 hours ago, Water Dawg 6 said:

Concur!  Even with a closed system that impeller pushes the water through the pump to cool the engine.  I was 20 miles off shore and I started over-heating - come to find out one of my water pumps got sand it from the week before and it tore up my impeller.  Had to change it out on the water in order to get home.  Easy to do with Bravo Outdrives but I think with the Alpha outdrives the impeller is located inside the lower unit. 

Your right, on a alpha its in the drive. Volvos are even easier to change out.

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I dont carry the old one, if you change it on a regular basis. No need.

 

 

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Until you get a trash bag wrapped around your outdrive and burn one up due to no water flow.... BTDT. Glad I had a spare!

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6 hours ago, Phillbo said:

Until you get a trash bag wrapped around your outdrive and burn one up due to no water flow.... BTDT. Glad I had a spare!

So true. Upper Delaware River around Phila. is a prime region for that particular failure.

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Down here in the North Carolina outbanks, I'm more concerned about hitting shoals, Maps and Chartplotters are useless around here.  But I do carry a spare impellers and a spare belt as well. 

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Every weekend I watch the water for ANY TYPE OF PLASTIC............ A simple sandwich bag is dangerous. Or a falling apart diaper. Plastic table cloths after or during outdoor parties with high winds. Holiday weekends & for days later . The after sundown speed freaks are busy chopping up all plastic stuff to get sucked into intakes. Amazing how the pumps work with so much plastic around the blades.

A slow constant rise in running temperature is cause to check inlet slots. raw water Pump vanes.  Thermostat. Circulating pump vanes.  1 or several of those can gradually become partially clogged. 

I knew a family that chopped up 1/8" diameter floating plastic lines & spread them around for the annoying PWC to destroy their pumps. It convinced the jets to stay out of their area.

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