2000 Volvo Penta 3.0 Overheating problems

[scb1712]

Hi All,

I just purchased my first boat, a 2001 Glastron SX 175 and it appears i've made every mistake possible :facepalm:. The boat was used in salt water for the first 8 years, but has been brought up to Canada and run in fresh water ever since. The previous owner put about 30 hours on in last season, but the boat overheated on his last outing. During the winterizing, he had a new impeller installed and pulled out lots of pieces of the old one at the inlet side of the circulating pump.

On our first outing this year, we ran into problems with the boat overheating badly (225 deg) after only about 5-7 min of running between 2500-3000 rpm. After shutting it down, and letting it cool, we were able to nurse it back to the dock keeping it at idle or just above (where she stayed around 180 deg).

So far, we've pulled and inspected the impeller and it's in seemingly good shape. I might replace it just to be safe. We have flushed all of the lines etc. and seem to get water flowing all the way through. However, the water presssure coming out of the impeller (when running with muffs on) was quite poor as i could stop it by placing my thumb over the hose.

We also noticed that there was no thermostat installed so that has been ordered. In addition, we noticed that 3 of the 4 channels where water flows into the exhaust riser were completely blocked by rust/corrosion. A new riser is also on the way.

I'm just wondering if there is anything else we should be checking to try to get this issue solved.

Sorry for the long post, but any help would be much appreciated.

Thanks,

Scb

 

[Don S]

Re: 2000 Volvo Penta 3.0 Overheating problems

So far, we've pulled and inspected the impeller and it's in seemingly good shape.

What do you consider good shape? There is more to it than just cracked or missing vanes. Did all the vanes on the impeller straighten out within 5 to 10 minutes?
PS: they should be replaced every other year, along with the gasket or oring on the housing. Air leaks will kill ya.

In addition, we noticed that 3 of the 4 channels where water flows into the exhaust riser were completely blocked by rust/corrosion. A new riser is also on the way.

What shape was the manifold in? Do you boat in salt or brackish water?
One note, the gasket covers 3 of the 4 openings.

 

[scb1712]

Re: 2000 Volvo Penta 3.0 Overheating problems

What do you consider good shape? There is more to it than just cracked or missing vanes. Did all the vanes on the impeller straighten out within 5 to 10 minutes?
PS: they should be replaced every other year, along with the gasket or oring on the housing. Air leaks will kill ya.

All the vane straightend out within seconds of being removed from the housing. There are no cracks etc. Just minor wear to the bulbs on the vanes on one side. I will replace the O-ring and gasket just to be sure.

What shape was the manifold in? Do you boat in salt or brackish water?
One note, the gasket covers 3 of the 4 openings.

As for the manifold, from what we can see it seems to be in good shape, but we're going to pull it off tonight to inspect it fully. Is it possible to have it sandblasted to remove any corrosion while it's off or do we need to replace it? We boat in exclusively fresh water

 

[Don S]

Re: 2000 Volvo Penta 3.0 Overheating problems

If you are only using it in fresh water, and the previous owner used it only in fresh water, I can't imagine anything in the exhaust system plugging up with rust in 10 years. There are boats out there that are 40 years old with prefect exhaust manifolds and risers.
I would bet you have an air leak between the drive and the pump. plumb in a clear hose at the raw water pump inlet hose and while in the water see if you see a lot of air bubbles.

 

[scb1712]

Re: 2000 Volvo Penta 3.0 Overheating problems

If you are only using it in fresh water, and the previous owner used it only in fresh water, I can't imagine anything in the exhaust system plugging up with rust in 10 years. There are boats out there that are 40 years old with prefect exhaust manifolds and risers.
I would bet you have an air leak between the drive and the pump. plumb in a clear hose at the raw water pump inlet hose and while in the water see if you see a lot of air bubbles.

The boat was run in salt water from new (2001) until 2009 in Florida before being brought up to Canada by the guy I bought it off. However, I will certainly try to plumb in a clear hose as you suggest.

 

[Don S]

Re: 2000 Volvo Penta 3.0 Overheating problems

After 9 years in salt water, you need a new manifold as well as the riser.

 

[scb1712]

Re: 2000 Volvo Penta 3.0 Overheating problems

Would that be the case even though there are only about 150 hours on it?

 

[Don S]

Re: 2000 Volvo Penta 3.0 Overheating problems

Would that be the case even though there are only about 150 hours on it?

In general yes, because even flushing after uses doesn't get rid of all the salt. Sometimes it's even worse.
Since the thermostat was already out, the previous owner probably knew there was cooling problems. Another thing is the hour meter. They are usually not an OEM item, who knows when it was installed. Could have been 2009.

 

[scb1712]

Re: 2000 Volvo Penta 3.0 Overheating problems

Thanks for all the info so far. Is there anything i should be checking on the stern drive as well? Also - i've discovered that some of the OMC 3.0 motors now recommend the same volvo part number as a replacement manifold. On the Volvo Penta of the Americas - OMC Cross reference list it shows that OMC manifold 3854045 is now replaced with Volvo Manifold 3858870 which is the same manifold i require.

However, the original OMC manifold is still available at $200 less than the Volvo one. Any idea if the OMC would work on the Volvo given that the Volvo part works on the OMC??