Volvo Penta 5.0 GL-E with SX outdrive temperature Fluctuation

[mrsgms]

Hello,
My impeller shredded. I replaced it and the thermostat. Opened entire cooling system and cleaned out all impeller pieces. Flushed entire system 3 times. Ran with muffs. Temp held at 175 (usual operating temp). Next day ran again. Temp holds for a few minutes then fluctuates between 175-195. After a few more minutes will fluctuate between 195-210. This continues until it reaches 210-220, at that point I shut it down. I have good flow when running. Can hook up garden hose to flushing hose and run engine and will hold at 175. Have disassembled, flushed and removed all visible impeller pieces several times. Any suggestions would be greatly appreciated.

 

[GA_Boater]

Welcome aboard.

Muffs don't count when working on an overheating problem. House water pressure vs impeller water pressure.

I'm guessing an impeller chunk is still blocking the water path.

 

[mrsgms]

Thanks GA. I'll try one more massive flush.

 

[harojs]

Check for flappers in exhaust elbow that have deformed due to overheat and fallen down into Y-pipe hence now restricting water flow. Common prob with VP/SX after overheating.

 

[skydiveD30571]

Check for flappers in exhaust elbow that have deformed due to overheat and fallen down into Y-pipe hence now restricting water flow. Common prob with VP/SX after overheating.

A Volvo GL-E engine won't have flappers. Volvo discontinued using them way before that model went into production. You're right that it is a common problem, just on earlier models.