Engine overheating/Volvo Penta 5.7 2003 Raw Water Cooled

[Chasin 46]

I own a Chaparral Cruiser I/O with 59 hrs....today I took it for a spin and it overheated after 15 minutes out on the water. The alarm sounded when the temperature reached 200 deg. After waiting for the engine to cool down we checked the raw water intake and there no obstruction. Went back to the dock and after two hours took the boat out. After 10 mins. the engine heated up again. Any thoughts as to why this could be happening? Possible impeller damage or defective themostrat. The boat is stored in a boatel and had not been out in the past three weeks. Thanks for your help.

 

[chris in va]

Re: Engine overheating/Volvo Penta 5.7 2003 Raw Water Cooled

I think you're on the right track. The thermo or raw water pump may be at fault. The thermostat is easier...

 

[rodbolt]

Re: Engine overheating/Volvo Penta 5.7 2003 Raw Water Cooled

Hello<br /> wow not many hours on it. the t-stat is easy to change.also check the power steering oil cooler if it has power steering. the tend to clog with grass sometimes. if the t-stat is good then look at the impeller. if the motor was ever started out of the water for any reason or service was done on it out of the water pull the pump. your pump should be mounted on the crankshaft front pulley. some boats its very difficult to access. being a 2003 model with only 59 hours its hard to believe any corrosion would have clogged it. sounds like somehow somewhere the impeller was run dry . good luck and keep posting

 

[Chasin 46]

Re: Engine overheating/Volvo Penta 5.7 2003 Raw Water Cooled

Hopefully we have fixed the problem. First we pulled the impeller and it looked fine. Secondly, we went to the thermostat and found it was very dirty and also inside the housing. The thermostat was shut and not open. We pulled the thermostat and flushed the engine for 25 minutes w/o the thermostat and the temperature stayed around 160-170 deg., which meant possibly a bad thermostat. Unable to find a new Volvo Thermostat we cleaned the thermostat with goof-off and placed it in boiled water to see if would open, which it did. Put the old thermostat back in and took the boat for a hard run and the temperature never rose above 160-170 deg. Hope this works and we're planning to replace the thermostat when the boat is winterized. Your comments or concerns would be appreciated.