volvo/chevy small block water pump

[pine island fred]

Replacing trim cyl hoses this evening on a 290DP. I am outside man, friend gets to do the inside work. As we are both tired of repairing this thing I comment that we should check the water pump vanes as it is a 91 , small block chevy, salt water cooled. Friend says he replaced the jabsco raw water pump last year, and he did, and thats the only water pump. I scratch my head, grab a flash light and look behind the big pulley where the fan would go. Nothing but a pile of rust behind there and impossible to tell if there is a pump or a cast water distribution block. He has the books in his truck and i have the question. Is there a regular chevy pump behind the pulley or is it just cooled by the jabsco pump? thanks fred

 

[Don S]

Re: volvo/chevy small block water pump

Yes, there is a pump there, that looks just like an automotive pump. On a boat, it called a circulating pump. The one with the rubber vanes is called a raw water/or sea water pump.<br />The circulating pump while it looks like the automotive, the insides are built to withstand the rigors or marine use.

 

[Peter J Fraser]

Re: volvo/chevy small block water pump

You have 2 water pumps.<br />The Sea water pump brings the water up to the thermostat hsg which passes the bulk of the flow through the manifolds and eventually overboard via the exhausts.<br />BUT the thermostat hsg also diverts water to the inlet of the block recirculating pump on demand as the water temp rises and this pump flows coolant through the block and heads exiting at the thermostat hsg and rejoining the water flow towards the exhausts etc.<br />You need to check the block w/p and make sure you use a marine pump to replace it as the impellor etc is stainless steel to resist the salt attack.<br />It looks like a std auto pump outside but is different internally.<br />You should also check that the thermostat is fitted and the correct type as the wrong unit may cause overheating also.<br />Regards<br /><br />Peter

 

[pine island fred]

Re: volvo/chevy small block water pump

Thanks guys, thought there might be something else. good to hear the pump has stainless impellers as although the boat has a fresh water flush system there is no guarantee it has been used sisce 91. Will assume it is a standard chevy pump gasket. fred

 

[Don S]

Re: volvo/chevy small block water pump

Ya Know, every time I assume something it bites me in the A$$.<br />But it is just a standard Chevy gasket.