Volvo Penta 5.7 Overheating

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shu5720

Seaman Apprentice
Joined
May 5, 2007
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33
Hi all. Looking for some help with this one. Replaced impeller yesterday and took boat out today. At low idle, within 10 minutes, boat started to overheat. Let it cool, started back up after a couple hours and within 2 minutes started to overheat again. Impeller looks fine - here's the concern. When I took apart the thermostat housing to get to the thermostat, there looks to be what's part or a piece of a ring (about an inch in height, 1/4 inch thick) sitting on top of the thermostat. No clue what it is? Any ideas? Any direction to head? Thanks!
 
Don S

Don S

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62,321
Re: Volvo Penta 5.7 Overheating

How about some information, besides being a Volvo V8, what year, what model, what drive.
Lots of different combintations over the years.
 
S

shu5720

Seaman Apprentice
Joined
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Messages
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Re: Volvo Penta 5.7 Overheating

It is a 2000 5.7L GX with Volvo Penta SX-B out drive. It is in a 2002 Four Winns 210 Horizon. It has the old accessory v-belt driven sea water pump.
 
S

shu5720

Seaman Apprentice
Joined
May 5, 2007
Messages
33
Re: Volvo Penta 5.7 Overheating

I just finished pulling the thermostat housing. The T-stat looked pretty beat up like it was run dry so I took it out, took the housing apart and cleaned everything. I cant tell if the T-stat is beat up because it failed of the recirculation pump did so I put it back together without the T-stat in it and ran if for a few minutes. Same problem, runs okay for a few minutes then, when the temp starts to climb, it never stops, goes up past 200 and I shut it down to prevent problems. I'm thinking recirculation pump but there were no obvious signs such as noise, leaks etc. Wanted to check with the experts.
 
S

shu5720

Seaman Apprentice
Joined
May 5, 2007
Messages
33
Re: Volvo Penta 5.7 Overheating

Sorry. The boat was repowered in 2004. I was told it was a replacement engine. 5.7L with 325 hp. I looked for ID tags shortly after I bought it but cant come up with any that make any sense. I can describe it to narrow down the application but have no definite answer. Would the recirc pump going cause it to do this?
 
S

shu5720

Seaman Apprentice
Joined
May 5, 2007
Messages
33
Re: Volvo Penta 5.7 Overheating

I pulled the inlet hose from the seawater pump and started the engine. No water flowed from the seawater pump to the thermostat. Is there a way to check that the seawater pump is operating properly?
 
S

shu5720

Seaman Apprentice
Joined
May 5, 2007
Messages
33
Re: Volvo Penta 5.7 Overheating

Just pulled the seawater pump and disassembled. Everything appears to be good, no bearing noise, excessive play. Even the impeller looks good, no signs of overheating. It just doesn't seem to be pushing any water. Have no clue where to go from here. Thanks - schu
 
S

shu5720

Seaman Apprentice
Joined
May 5, 2007
Messages
33
Re: Volvo Penta 5.7 Overheating

thanks. I am downloading it now. Will start again in the morning. I'll let you know how it goes.
 
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