OverHeating GM Straight 6 Cylinder

[killerfish]

Hello All, I'm having an overheating problem with my inboard motor. It is a 76 GM straight 6, and my question is; Is there a way to test my water pump (engine mounted), before I shell out good money to replace it?

 

[CharlieB]

Re: OverHeating GM Straight 6 Cylinder

A more common cause is the water pump impeller in the outdrive, has that been service within the last 2 years?

How old is the T-stat?

 

[killerfish]

Re: OverHeating GM Straight 6 Cylinder

Just replaced the thermostat, and the impeller. But i was wondering if there was a way to test the waterpump, other than getting back out on the lake, and waiting to see if it overheats again.

 

[Haut Medoc]

Re: OverHeating GM Straight 6 Cylinder

Are you referring to the engine circulating pump?.......
If you changed the t stat & impeller, put it on muffs & see what happens......
How much water is coming out of the exhaust?......
Other than leaking, they rarely go bad......
I doubt very much if it is the cause.....​

 

[Bondo]

Re: OverHeating GM Straight 6 Cylinder

Nope,...... Not really.......

The Circulating Pumps rarely go Bad,.... When they Do,.....
They usually Leak thru the front seal.......

The Impeller is the Mosy Common Problem......
2nd Most Common is lost pieces of an old Impeller that move Up-stream,+ block the flow.......



Ayuh,...... HoMeDoe,....Ya got in under me Again,....................

 

[killerfish]

Re: OverHeating GM Straight 6 Cylinder

I guess it is called the circulating pump. It is located on the front of the motor, and is belt driven. When i hook up the water hose, it seems as though all is working well, but I can't tell for sure. Plenty of water is coming out of the muffs while it is running. Did I have the pressure on the hose too high, for a good test.