2003 Volvo 5.0 GL-D overheating, SX-M Out drive, Glastron GS209

Dennispell

Cadet
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Dec 8, 2015
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8
I purchase this boat in 2014 with 199 hours in fresh water lakes. It now has 325 hours in salt water.
This boat overheated for first time after being on trailer for 4 months in warm weather. I brought it on the trailer to a Volvo Authorized Service Center in Galveston County Texas and they replaced the impeller which they said was spun rather than broken. I did not test the repair myself, but had it placed back on the trailer for 9 months of outside storage starting in November. I drained the water and filled hoses with antifreeze. I relaunched the boat the following August and had intermittent overheating. It overheats when run at full throttle for any length of time, but will run at 3000 RPM all day without overheating. Overheating is confirmed by two different IR temperature sensors.

I brought it back to the same Volvo Authorized Service Center and they replaced raw water pump and declared it fixed. I picked it up and took it for 5-minute test drive and brought it back. Still overheated at 4500 RPM. They took out thermostat and it tested as okay, but they replaced it anyway. They also recommended replacing manifold gaskets and removing lower unit to check connections for cracks and leaks and flush water inlet system. All of which was done. Engine still consistently overheats at high RPMs.

They are stumped and when I introduced them to the clear hose, pressure and vacuum gauge tests recommended by Volvo they showed little knowledge or interest.

I have subsequently replaced both belts, replaced the thermostat again and checked hoses and thermostat housing for any blockages. There has been no change.

I had noticed water leaking from the new raw water pump and was told by the Volvo Authorized mechanic that it might be due to faulty pulley seals drying out while sitting and those could also be letting air into the system. They supposedly did an on-water test without any further leaks.

I have now installed clear hoses at the raw water pump on the inlet and outlet hoses. The inlet hose shows zero air whereas the outlet hose has much air. I also saw water dripping out of what appear to be weep holes in the raw water pump while I was removing the hoses to install clear hoses. There are no other leaks into the bilge under the engine.

Here is my question, is there any way for the pulley seals to be allowing air to enter the pump and water flow? From what I am seeing in the after-market manuals it doesn?t look like this could happen. Yet there do seem to be weep holes in the pump housing so what are these for and what is causing them to drip water? HELP!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Find a new mechanic

Yes, bad seals could introduce air. So could a bad raw water inlet fitting

Have you inspected your risers and manifolds?
 

Dennispell

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Dec 8, 2015
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I have inspected my risers and manifolds and they are good. Given the amount of air that is entering the flow from the raw water pump it seems pretty likely that is is the problem especially since the boat runs extremely well except for overheating at full throttle. The water pump has been replaced with an all metal one which should eliminate the problem that the earlier Volvo pumps had with air leaks where the plastic and metal were pressed together. So where is the air coming from? The mechanic said that the pulley seals could allow air into the system, but it seems like the seals for the pulley would be around the crank shaft to prevent oil coming out and water going into the crankcase. How would those allow water to leak into the bilge?
 

skydiveD30571

Lieutenant Junior Grade
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Feb 13, 2012
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Out of curiosity, you might want to pull the front of the pump containing the impeller again and make sure there's one o-ring and one o-ring only between it and the sealing surface. If the mechanic forgot to put one on, or added a second one, it can create air leaks there. A lot of times the o-ring doesn't come off with the front of the pump so people assume there wasn't one on there before.
 

Fishhead-1

Petty Officer 2nd Class
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Oct 10, 2003
Messages
110
I have inspected my risers and manifolds and they are good. Given the amount of air that is entering the flow from the raw water pump it seems pretty likely that is is the problem especially since the boat runs extremely well except for overheating at full throttle. The water pump has been replaced with an all metal one which should eliminate the problem that the earlier Volvo pumps had with air leaks where the plastic and metal were pressed together. So where is the air coming from? The mechanic said that the pulley seals could allow air into the system, but it seems like the seals for the pulley would be around the crank shaft to prevent oil coming out and water going into the crankcase. How would those allow water to leak into the bilge?

He means the raw water pump seal that seals the pump shaft, by the sealed bearing. That seams like your problem. Did you remove your exhaust risers to check for internal plugging? Lots of information here about manifold risers problems and the damage they will cause in saltwater.
 

Dennispell

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Dec 8, 2015
Messages
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Yes the risers look fine which isn't surprising since the boat only has 125 hours of salt water use over 3 years. Prior to that it lived in fresh water lakes and I've also been doing fresh water flushes after each use for the last year. Is the seal you mentioned the one that slides over the crankshaft before installing the raw water pump cover? The raw water pump cover has been replaced but not the pulley and pump base.
 

Fishhead-1

Petty Officer 2nd Class
Joined
Oct 10, 2003
Messages
110
Yes, the seal is on the pulley shaft of the pump. You can replace seal but would be best to remove pump assembly to do repair.
 

Dennispell

Cadet
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Dec 8, 2015
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How difficult is it to remove the pump assembly? Will I need to use a gear puller to get the old pump off of the shaft?
 

dypcdiver

Lieutenant Junior Grade
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Nov 1, 2005
Messages
1,016
Pump is held on the balancer by 3 Allen cap headed bolts 5/16 or 8mm AF. They are tight so you might need a length of pipe to extend the Allen key.
Don't mess about replace seal and bearing. otherwise you will be doing the same job again. Plenty of Ytube videos, just search there and on here details of seal and bearing also on here so you can pre purchase. it is a very easy job.
 

Dennispell

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Dec 8, 2015
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8
Oops, I didn't see your response. Thank you all for the information. I now have a plan that I think will work. Fantastic!
 

Dennispell

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Joined
Dec 8, 2015
Messages
8
Great news, the overheating is fixed!!! It was the raw water pump seals. I purchased a new Volvo water pump and hired a mechanic to install it. After installation we ran it for a few minutes in the slip to purge the air from the lines and once that was done there were no more air bubbles. We then took it out and ran it at top RPMs for about five minutes and the temperature held steady. Previously it would seriously overheat after about a minute.

Thank you everyone for all your great advice. I couldn't have done it without you and the Volvo Overheating Diagnostic Procedure available here
http://forums.iboats.com/filedata/fe...9&d=1356821532
 
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