Volvo Penta 5.7 Overheat Please Help

[tvigg27]

I have a volvo Penta 5.7 that just recently started to overheat. I am getting over heating at idle, if i give it some rps or wot the temp levels off to normal. I just replaced the impeller with no luck. Also if i attach the garden hose to the flush the temp also stay normal and does not overheat. Please give me some input on what can cause this. Thanks Tom

 

[skydiveD30571]

Re: Volvo Penta 5.7 Overheat Please Help

Is this a raw water cooled or closed cooling system? You are sucking in air somewhere. Sounds like you aren't getting enough water at idle but at higher rpm's the impeller is creating more suction and pulls more water, cooling it down.

Are you saying your overheat only happens in the water at idle speeds, and on the hose you have no problem?

 

[mikeneal]

Re: Volvo Penta 5.7 Overheat Please Help

Somewhere Don S. posted a really nice VP overheat troubleshoot article, he will probably chime in with the link or search for it thru his name.

 

[Don S]

Re: Volvo Penta 5.7 Overheat Please Help

I have a volvo Penta 5.7 that just recently started to overheat.

Volvo has been using the 5.7 for 40 years, might be helpful if you gave us a year and a model number, maybe a serial number so we could figure out what your cooling system is.

Somewhere Don S. posted a really nice VP overheat troubleshoot article, he will probably chime in with the link or search for it thru his name.

It's in the sticky at the top of this forum.

 

[tvigg27]

Re: Volvo Penta 5.7 Overheat Please Help

The engine is a raw water cooled, year is a 2006 5.7 gi-e. The engine overheats at idle, high rpms it cools down and stays at norm temp. If I hook up the garden hose at idle the engine does not overheat until I disconnect the hose. Thanks for the help.

 

[Don S]

Re: Volvo Penta 5.7 Overheat Please Help

How old is the impeller in the raw water pump?

 

[vwbugman69]

Re: Volvo Penta 5.7 Overheat Please Help

I had the same issue and it turned out to be two orings between the pump and housing. Did you remove and replace the original oring when you changed the impeller?

 

[tvigg27]

Re: Volvo Penta 5.7 Overheat Please Help

The impeller was just changed begin of season, not sure about the O rings need to check them and get back to you. Bad O ring would cause air to be drawn in?

 

[security6]

Re: Volvo Penta 5.7 Overheat Please Help

I had the same issue due to an older style impeller housing. Some of the older style impeller housings had 3 parts - a brass circular housing to hold the impeller and two plastic hose mounts glued to the brass housing. New style housings are solid brass - all 1 piece.

Anyway, what happened on mine is I got an air leak on the intake side between the plastic house mount and the brass circular housing. At idle the air leak was big enough with respect to the flow that the engine wasn't getting enough water. When the engine was revved more water was being sucked in, so the air leak didn't have much of an effect.

The leak was apparent because the intake house mount would wobble slightly when I tried to move it with respect to the brass circular housing.

 

[skydiveD30571]

Re: Volvo Penta 5.7 Overheat Please Help

The impeller was just changed begin of season, not sure about the O rings need to check them and get back to you. Bad O ring would cause air to be drawn in?

Sure. Afterall, an o-ring is there to seal the pump and not let air leak in. If your o-ring is bad, air gets in.

What vwbug was saying though, is that it is a common mistake to not take the old o-ring off when changing impellers and then putting the new o-ring and impeller on. Having two o-rings on there will not seal the pump properly.

 

[dacarter]

Re: Volvo Penta 5.7 Overheat Please Help

Greasing the O-ring is important too. I had a leak when I put mine back together without greasing it, but after re-reading the instructions, I greased it and the leak was gone.

 

[baker7007]

I am having the exact same problem. Replaced the impeller, thermostat, and rubber grommets in lower drive. How do I know if impeller housing is bad? Any other things to look at? Thanks

 

[baker7007]

@ Don S - where can I find a link to the overheat article?