Volvo 3.0 GS Overheats

PJFWH170

Cadet
Joined
Sep 16, 2010
Messages
21
My 2000 Volvo 3.0 GS will run @150-160 degrees all day long at 3500 RPM or less. At 3500 and above the temp starts rising and at WOT move toward overtemp. When this happens I reduce the RPM and the temp falls quite rapidly back to the 150-160 level. I removed the thermostat and it obviously runs cold at RPM's less than 3500 but when I run @WOT the temp would creap up to 180-190. The engine has new wires,plugs,distributor cap,rotor,new circulating pump,new raw water pump and thermostat. Sounds like a blockage somewhere but don't know where to start.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Volvo 3.0 GS Overheats

If you run in salt water, the exhaust manifold and riser could be plugging up. Remove the riser and inspect the passages.
 

PJFWH170

Cadet
Joined
Sep 16, 2010
Messages
21
Re: Volvo 3.0 GS Overheats

This has been a fresh water boat from day 1. I thought I read somehwere that there is some kind of a mechanism in the exhaust that prevents water from backing up into the manifold if you launch the boat to fast.
 
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