Air bubbles in coolant overflow tank

[Straydog]

I don't seem to be having much luck in my restoration project on the LX565. I recently noticed air bubbles (about 3 bubbles a second) in the coolant overflow tank. No sign of water in the oil or any other problems though. I'm assuming this is a head gasket gone?? The engine is not the original Shibaura but a 2.2 liter Perkins which looks almost identical to the 2 liter Shibaura. I cant say for sure but I think the engine is about 13 years old. Is the head gasket a common problem with these engines and a likely cause of the air bubbles? I'm annoyed I didn't see the problem when I tested the engine before I bought it. The bubbles aren't always visible, but seem to be there when the engine is fully warmed up.

 

[mfyock]

I had an LX machine that had a similar issue. It would bubble into the rad and push cooland out of the rad. Couldnt keep the rad fuller than 1" from the top. The 2.2 liter had a lot of head gasket issues in the beginning. Especially in the CAT machines. The cat used the 3024c, which is the same engine... More than likely you have a slightly blown gasket that is allowing compression from one of the cylinders to pressurise the cooling system. You could try torqueing the head bolts to spec and see if that helps.

 

[Tazza]

I had an LX machine that had a similar issue. It would bubble into the rad and push cooland out of the rad. Couldnt keep the rad fuller than 1" from the top. The 2.2 liter had a lot of head gasket issues in the beginning. Especially in the CAT machines. The cat used the 3024c, which is the same engine... More than likely you have a slightly blown gasket that is allowing compression from one of the cylinders to pressurise the cooling system. You could try torqueing the head bolts to spec and see if that helps.

Hopefully it is just a gasket, i do't know how prone heads are to cracking. Kubota heads crack all the time if they get hot.
Don't be too hard on your self, it's not always easy to check for bubbles in the coolant unless the engine is setup with a cooling system when you go to buyt it.

 

[samsonite]

I did the head gasket on my shibaura 844, If you have any questions I can help you out. it wasn't a bad job, I think I had about $500 into it and that included head work.

 

[Straydog]

I did the head gasket on my shibaura 844, If you have any questions I can help you out. it wasn't a bad job, I think I had about $500 into it and that included head work.

I think I'll price up a head gasket but maybe just monitor the situation and change the head gasket when I get some time. I bought a new radiator cap but later noticed that the one that was on it was a 7 pound relief. The one I bought was a 14 pound relief. Does anyone know what pressure radiator cap it should be?

 

[samsonite]

I think I'll price up a head gasket but maybe just monitor the situation and change the head gasket when I get some time. I bought a new radiator cap but later noticed that the one that was on it was a 7 pound relief. The one I bought was a 14 pound relief. Does anyone know what pressure radiator cap it should be?

I belive you should run a 7 pound cap. The later tier 2 engins ran a heavier cap, but i thought it was a 13 pounder. Check messiks online they will know for sure. Are you loosing any coolant externally, or is the overflow bottle loosing it's level?

 

[Straydog]

I belive you should run a 7 pound cap. The later tier 2 engins ran a heavier cap, but i thought it was a 13 pounder. Check messiks online they will know for sure. Are you loosing any coolant externally, or is the overflow bottle loosing it's level?

I checked Messiks, part number 90-7731T1, but it doesn't say what pressure it is. The dealer here in Australia wanted $50 for the part that Messicks sells for $11.50 even though the Australian dollar is worth more than the US dollar. Hence I bought an aftermarket cap but I might go back and get a 7 pound one instead. I only use the machine very occasionally at the moment and so far haven't lost any coolant externally. The overflow bottle did fill right up though and it didn't really suck any back in when the engine cooled down so I thought I would replace the cap as the seals looked a bit worn.

 

[Mike10]

I checked Messiks, part number 90-7731T1, but it doesn't say what pressure it is. The dealer here in Australia wanted $50 for the part that Messicks sells for $11.50 even though the Australian dollar is worth more than the US dollar. Hence I bought an aftermarket cap but I might go back and get a 7 pound one instead. I only use the machine very occasionally at the moment and so far haven't lost any coolant externally. The overflow bottle did fill right up though and it didn't really suck any back in when the engine cooled down so I thought I would replace the cap as the seals looked a bit worn.

From the service manual

SPECIFICATIONS​

Capacity - 10.8 qts. (10.3 L)
Mixture - 50/50 antifreeze/water​

Radiator cap - 7 PSI (48.3 kPa)