2002 Volvo Penta 5.7gi-b engine overheating

[TJoyner]

Engine overheats with alarm and stalls engine after plane. Dashboard temperature gauge shows normal, but engine is hot around oil filter. Is it thermostat?

 

[dubs283]

Is it thermostat?

Not likely, most likely the sea water pump impeller has failed and needs replaced

 

[Scott Danforth]

Welcome aboard. Is this a new to you boat, or have you had it for a while? What maintenance did you do?

 

[TJoyner]

Not likely, most likely the sea water pump impeller has failed and needs replaced

Impeller has been replaced.

 

[TJoyner]

Welcome aboard. Is this a new to you boat, or have you had it for a while? What maintenance did you do?

Welcome aboard. Is this a new to you boat, or have you had it for a while? What maintenance did you do?

I’ve had it from day one. I’ve changed oil, gear oil, oil filter, fuel filter and steering actuator in the past few weeks. Just getting it ready for the summer. It’s been garage stored all along. Since Covid, we’ve only had it out 1-2 times.

 

[Scott Danforth]

I’ve had it from day one. I’ve changed oil, gear oil, oil filter, fuel filter and steering actuator in the past few weeks. Just getting it ready for the summer. It’s been garage stored all along. Since Covid, we’ve only had it out 1-2 times.

when was the raw water pump impeller changed?

did you pull the drive and inspect the bellows, u-joints, and Gimbal?

 

[TJoyner]

Impeller was changed last year and I pulled it this year and it looks perfect but I do have a drip and have tried a few times to reseat it. No I have not pulled the drive to inspect bellows, ujoints and Gimbal.

 

[TJoyner]

This is a freshwater engine.

 

[alldodge]

With boat in the water remove the hose going to the thermostat housing from the water pump. Start the motor and see if it come gushing or barely pouring out

 

[Scott Danforth]

Dont forget to inspect the fitting on the drive that the raw water supply hose connects to. That fiting often corrodes.

Overheat is a lack of cooling water flow

The leak from your raw water pump could also be an air leak causing the pump to loose prime.

When you changed the impeller last year, did you find all the missing pieces?

 

[TJoyner]

Dont forget to inspect the fitting on the drive that the raw water supply hose connects to. That fiting often corrodes.

Overheat is a lack of cooling water flow

The leak from your raw water pump could also be an air leak causing the pump to loose prime.

When you changed the impeller last year, did you find all the missing pieces?

I'll check the raw water supply hose today. The impeller was good when I changed it, no pieces missing...just wanted to make sure it was good.

 

[TJoyner]

With boat in the water remove the hose going to the thermostat housing from the water pump. Start the motor and see if it come gushing or barely pouring out

Could I do this with a muffler hose? I won't have it in the water today.

 

[dubs283]

Impeller was changed last year and I pulled it this year and it looks perfect but I do have a drip and have tried a few times to reseat it. No I have not pulled the drive to inspect bellows, ujoints and Gimbal.

Looks perfect and performs properly are two different things. Even though the impeller looks okay it does not mean it works okay. Often times the impeller has a set that causes it to not pump enough water to cool properly, this is especially true of aftermarket impellers.

Is the drip from the housing cover or the shaft? Could be the shaft seal has failed and pump is drawing air

Try the test suggested above and check for proper flow at t stat housing. Test can be performed on muffs with full water supply from hose. I would also check supply to the pump from the drive by backflushing the supply hose

 

[alldodge]

Could I do this with a muffler hose? I won't have it in the water today.

Water will come in from the pressure of the hose and not just the pump

 

[alldodge]

Another way and less mess but still needs to be in the water. Get a short piece of clear hose and a double barbed fitting from hardware store. Should be about 1 inch ID. Place it between T stat and hose from pump.

Your looking for bubbles when running