4.3 Volvo GXI air bubbles in cooling system

[crawdaddy]

I have an overheating problem that started at the begining of the season this year. Both the impeller or thermostat were fine. I replaced both of them since I had things apart. I put clear hoses inline past the impellar and can see air bubbles.

Does anyone know any tricks to find where the air is entering prior to the impellar pump?

There is not a straight hose between the impellar pump and the drive. There are smaller hoses that split off to cool the power steering and oil filter housing. There is also a inline flush connector. I checked that to assure it is screwed on tight.

 

[Bondo]

Re: 4.3 Volvo GXI air bubbles in cooling system

There is not a straight hose between the impellar pump and the drive.

Ayuh,.....

Isolate this area of the system,+ Block it off at both ends,....
Plumb it a way to pressurize it with Air(10/ 15psi),......
And,...... Listen........
If you don't Hear the Leak,..... Squirt some soapy water at all the connections.....

 

[Don S]

Re: 4.3 Volvo GXI air bubbles in cooling system

Put that clear hose on the SUCTION side of the pump and check for air with the boat in the water, not on muffs.

 

[crawdaddy]

Re: 4.3 Volvo GXI air bubbles in cooling system

I Air tested the hoses back to the drive unit and they held 10PSI just fine. I Also put a clear hose just before the Impellar pump and I saw air bubbles.

The air is comming in somewhere past where the tube attaches to the lower unit on the back of the boat. Is there anything that I can check on the lower unit?

Thanks,

 

[Don S]

Re: 4.3 Volvo GXI air bubbles in cooling system

What year is this 4.3GXi? Or better yet, FULL model number, including any letters after the 4.3GXi. What drive do you have.
Have you done any drive work?
Do you have raw water cooling, or a closed cooling system?

 

[crawdaddy]

Re: 4.3 Volvo GXI air bubbles in cooling system

I have not done any drive work before.
It is a raw water system.

All of the dealers here are out two weeks for repair time and I have a family vacation on the lake next week. If it is not to hard I am more than willing to pull the drive if needed.

Here is the info.

Transom
tsk-sx-m

Drive
sx-m 1.60
3868891

Engine
4.3 GXI-E
3869252
4012116004

Thanks,

 

[Don S]

Re: 4.3 Volvo GXI air bubbles in cooling system

Do you have a Neutra Salt system installed on this boat? Does it suck air and overheat at idle, or only at higher speeds.

 

[Don S]

Re: 4.3 Volvo GXI air bubbles in cooling system

Here are some possibilities. Assuming no one has taken the drive apart (upper from the lower unit)
1. The seal ring #6 leaking or out of place between the drive and bellhousing
2. Fitting #8 is plastic and could be cracked.
3. Not sure where exactly you stopped the air to pressurize the hoses, but hose #9 could have loose hose clamps or hole in the hose.
4. Have seen holes in fitting #10 before
5. The #5 with arrow pointing to back of drive, there is a plate with a gasket held on with 4 bolts. Gasket could leak, but I doubt it.

Now, if you have bubbles indicating air only when on plane, the gaskets #4 and #2 could be out of place on the pipe #3.

 

[crawdaddy]

Re: 4.3 Volvo GXI air bubbles in cooling system

I dont think I have the nutra salt sytem since I am in minnesota. I only looked for the air bubbles at idle. If this helps the oil in the lower unit was grey when I changed it last year.

On muffs in driveway it never goes above 140

At 2500 rpms it does not over heat . It never goes above 180

Once the engine is warm it over heats at Idle. climbs over 200. (lots of air bubbles)

At Full speed it overheats. It takes awile to do it though.

Would you recomend I let the dealer take apart the lower unit or is there a good manual that would give me enough info to get though it.

Thanks so much for all the detail.

 

[crawdaddy]

Re: 4.3 Volvo GXI air bubbles in cooling system

I put the muffs on and checked for any water leaks from hose 9 or b -- none that I could see.

The only thing i saw was that there was water comming out of the two holes that are just above and forward of the intake holes on the lower unit Not sure if that is normal.

 

[Don S]

Re: 4.3 Volvo GXI air bubbles in cooling system

Do you have a hose with a blue cap used for flushing the engine? if so, make sure it's tight (Hand tight plus an additional 1/4 turn).

 

[crawdaddy]

Re: 4.3 Volvo GXI air bubbles in cooling system

Don,

To test prior to removing the drive I was able to turn the drive to the right and remove hose 9 (looked ok) from B on the diagram. I attached a hose to B and put it in a barrel of water. Wala ??.. no air bubbles.

I put hose 9 back and then went for a test drive. I saw bubbles at all speeds.

I was trying to figure out how air bubbles could get into the cooling intake when the drive is completely underwater. I am assuming that the exhaust bubbles, in and around the drive, enter into the cooling intake leak.

I will not be able to get my hands on a manual before the weekend and I would like to take the drive off and repair it. Do you by chance have access to the manual pages or steps I would need?

Thanks again for your help.

 

[Don S]

Re: 4.3 Volvo GXI air bubbles in cooling system

To pull the drive off, just remove the shaft that holds the trim cylinders to the drive (remove cap and snap ring on end of shaft)
Remove the back plastic cover (3 bolts)
Disconnect the cotter pin holding the shift cable end to the shift linkage.
Remove the brass end on the cable. NOTE LOCATION of brass end so you can put it back in the same place.
Remove the 6 nuts holding the drive to the bellhousing.
Pull the drive off.

 

[crawdaddy]

Re: 4.3 Volvo GXI air bubbles in cooling system

How about the lower unit. I am assuming drain the oil, remove the bolts and pull it off?

When putting the lower unit and drive back do i use a gasket sealer of some sort?

 

[SLorg]

@crawdaddy, I am having similar overheat issues with the same engine. Did you ever find the source causing the overheat issue? Thanks