Volvo 5.7L GL-A Overheating

[sattler]

I have a 2002 Glastron GX205

It is powered by a 5.7L GL-A Volvo and has a Penta SX Drive. 255 Hrs

The boat has been overheating on me at Idle and low speeds, when you rev it up to about 1/2 throttle it will cool down or when on plane. Went out on Friday night and the boat will no longer cool down when revved up.

Hauled it home and starting to check things over. Raw water impeller looks good, the hose going to the hull of the boat is clear of any debris, The hose from the lower unit to the hull of the boat is clear of any debris. Put in a new thermostat, put in a new impeller and O ring. I am still overheating an won't cool down. I even tried revesing the raw water intake hose to the other side of the impeller housing to see if I switched the two houses around and still it won't cool. It seems to me that the impeller wont suck water up from the lower unit, I say this because when the boat is on the muffs the water that is spraying around should lessen as the boat pulls it through the lower unit.

 

[Don S]

Re: Volvo 5.7L GL-A Overheating

This file should help you track down the problem.

http://www.4shared.com/file/50572185/e88f1d89/Volvo_Penta_Overheat_Diagnosis.html

 

[lcolvin]

Re: Volvo 5.7L GL-A Overheating

I just went through something similar with my boat, however I was able to idle at ok temp.....it ended up being the grommit that is on the copper tube between the upper and lower unit...mine had split and was sucking air....Just something to think about if youve tried everything else first...

 

[belleview3]

Re: Volvo 5.7L GL-A Overheating

Yep, I had the same issue last year. Don's link to the overheating diag helped me. Used the clear hose setup and found I was sucking in air. ALOT OF AIR. Tore the lower unit out and found it was the $8 plastic adapter at the top of the unit to the hose from the transom.
Good luck.

 

[sattler]

Re: Volvo 5.7L GL-A Overheating

I have the problem fixed!

It turned out that the plate the backside of the water pump seals to was worn to deep. I ended up just buying an entire new water pump housing. That came with a new pulley, Impeller and outer housing cover.