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Volvo Penta 1997 4.3 GL Overheating

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pgorrell

Member
I have a 97 volvo penta gl that we just got off the lake with. Started day out cooling well and then started to creep up as the day went along. When I purchased the boat, it never would heat up and I replaced the thermostat and that seemed to fix the problem. I had order a new impeller to be replaced. Any other points I need to check after replacing the impeller. This boat has a raw water system. When I replaced the thermostat, it was incredibly rusty. I did notice also that bellows hose coming out of the transom to the lower unit has a huge crack in it. Not sure if that may be related to the problem as well.
 
pgorrell said:
I have a 97 volvo penta gl that we just got off the lake with. Started day out cooling well and then started to creep up as the day went along. When I purchased the boat, it never would heat up and I replaced the thermostat and that seemed to fix the problem.
1..... I had order a new impeller to be replaced. Any other points I need to check after replacing the impeller. This boat has a raw water system. When I replaced the thermostat, it was incredibly rusty.

2.... I did notice also that bellows hose (??????) coming out of the transom to the lower unit has a huge crack in it. Not sure if that may be related to the problem as well.
Click to expand...

1..... Seawater pump impellers are considered to be "wear items" and need to be replaced routinely.
All too often people tend to look at the thermostat as if being the problem, when it's actually a seawater supply issue.
I believe that your 4.3 GL will be equipped with the crankshaft pump. If so, these impellers are easy to R&R.
http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-26-6928.aspx


2..... Volvo Penta has always used an engine mounted seawater pump, of which means that the hose from the drive to the pump is a suction hose. A tiny suction breach (such as a crack into the hose interior) will cause an issue with the seawater flow, of which will cause an over-heating scenario.


You should also pull the exhaust elbows off, and inspect the seawater transfer ports for signs of rust scale that may be restricting seawater flow.
http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-25-6918.aspx


.
 
RicardoMarine said:
1..... Seawater pump impellers are considered to be "wear items" and need to be replaced routinely.
All too often people tend to look at the thermostat as if being the problem, when it's actually a seawater supply issue.
I believe that your 4.3 GL will be equipped with the crankshaft pump. If so, these impellers are easy to R&R.
http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-26-6928.aspx


2..... Volvo Penta has always used an engine mounted seawater pump, of which means that the hose from the drive to the pump is a suction hose. A tiny suction breach (such as a crack into the hose interior) will cause an issue with the seawater flow, of which will cause an over-heating scenario.


You should also pull the exhaust elbows off, and inspect the seawater transfer ports for signs of rust scale that may be restricting seawater flow.
http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-25-6918.aspx


I just replaced the water pump and is was shot. Should I be concerned with the rubber pieces that have come loose. If so, how do I flush the block of the motor. I am sure it is in the motor. I am going to take off the thermostat and start there because I am sure there will be some there. Any other places I should look and flush?
Click to expand...
 
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pgorrell said:
RicardoMarine said:
1..... Seawater pump impellers are considered to be "wear items" and need to be replaced routinely.
All too often people tend to look at the thermostat as if being the problem, when it's actually a seawater supply issue.
I believe that your 4.3 GL will be equipped with the crankshaft pump. If so, these impellers are easy to R&R.
http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-26-6928.aspx


2..... Volvo Penta has always used an engine mounted seawater pump, of which means that the hose from the drive to the pump is a suction hose. A tiny suction breach (such as a crack into the hose interior) will cause an issue with the seawater flow, of which will cause an over-heating scenario.


You should also pull the exhaust elbows off, and inspect the seawater transfer ports for signs of rust scale that may be restricting seawater flow.
http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744270-25-6918.aspx
Click to expand...



I just replaced the water pump and is was shot. Should I be concerned with the rubber pieces that have come loose.
I presume that you mean "seawater" pump!
The seawater pump impeller is made from a composite/rubber material.
If you lost impeller vanes, yes...... you should retrieve every one of them.


If so, how do I flush the block of the engine. I am sure it is in the engine. I am going to take off the thermostat and start there because I am sure there will be some there.
Unlikely that any could make it that far!

Any other places I should look and flush?
Look at the seawater flow direction from the seawater pump.
It first enters the T-stat housing where it then becomes mixed with seawater that is leaving the engine.
Any seawater entering the engine does so on "as required" basis depending on engine cooling demands as per the thermostat's open position.

Most all seawater goes on out to the exhaust system.
Click to expand...
 
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