We have an L305 DT that runs fine for the most part, but will overheat with the PTO going and the hydraulics get rocket hot. My first thought was a head gasket but the tractor runs good with no smoke on start up. The heat from the hydraulics makes me wonder if there is a cooler i am missing or is the hydraulics tied to the transmission? Any help would be appreciated as I am new to the Kubota world. Thanks
L305 DT oil in water and hot hydraulics.
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Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
There will probably not be a cooler on the tractor if is the older 1980s tractor that I assume it is.
I assume you mean the engine over heats when you use the rear PTO. The radiator on these are on the small side and must be clean inside and out. Clean the screen in front of the radiator if it is there. Clean the exterior fins from the rear with low pressure water and try looking through it with a light to see how clean it is. The battery is probably in front of the radiator radiator blocking some flow so make sure it is as far forward as it should be.
I believe it has a water pump and thermostat so check the operation of them by starting it cold and see if there is no water circulation and starts to circulation starts when engine gets warm.
What is hot on the hydraulic system?
Where is the oil and water mixed?
I assume you mean the engine over heats when you use the rear PTO. The radiator on these are on the small side and must be clean inside and out. Clean the screen in front of the radiator if it is there. Clean the exterior fins from the rear with low pressure water and try looking through it with a light to see how clean it is. The battery is probably in front of the radiator radiator blocking some flow so make sure it is as far forward as it should be.
I believe it has a water pump and thermostat so check the operation of them by starting it cold and see if there is no water circulation and starts to circulation starts when engine gets warm.
What is hot on the hydraulic system?
Where is the oil and water mixed?
Hi thanks for your reply. The water is in the radiator (milky white). The thermostat and gauge work fine
Thanks for the reply. The whole hydraulic system is hot, all the fittings, hoses, etc. to the point you cant touch it. The water in the radiator is milky white and this lead me to believe I had lost a head gasket but again I have no loss of power or smoking on start up (I am still going to check the head gasket). The water circulates fine in the radiator and the thermostat is operational. My concern was the heating of the hydraulics and wondering if that system could get into the cooling system. Any idea haw hard it is to change a head gasket on this little thing?
Hi Russell,There will probably not be a cooler on the tractor if is the older 1980s tractor that I assume it is.
I assume you mean the engine over heats when you use the rear PTO. The radiator on these are on the small side and must be clean inside and out. Clean the screen in front of the radiator if it is there. Clean the exterior fins from the rear with low pressure water and try looking through it with a light to see how clean it is. The battery is probably in front of the radiator radiator blocking some flow so make sure it is as far forward as it should be.
I believe it has a water pump and thermostat so check the operation of them by starting it cold and see if there is no water circulation and starts to circulation starts when engine gets warm.
What is hot on the hydraulic system?
Where is the oil and water mixed?
Thanks for the reply. The whole hydraulic system is hot, all the fittings, hoses, etc. to the point you cant touch it. The water in the radiator is milky white and this lead me to believe I had lost a head gasket but again I have no loss of power or smoking on start up (I am still going to check the head gasket). The water circulates fine in the radiator and the thermostat is operational. My concern was the heating of the hydraulics and wondering if that system could get into the cooling system. Any idea haw hard it is to change a head gasket on this little thing?
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
I don’t know exactly what makes the radiator water milky but it could be oil from the engine.
One way to see if it is a head gasket is to have the radiator cap off and start it from the cold engine condition. Then see if you can see any tiny bubbles in the radiator. I am not 100% sure this works for thermostat engines though.
The head is easy enough to get off but the recommendations are to only use the Kubota head gasket not aftermarket one. There is also (probably) a o-ring that seals around a “dowel pipe “ that must be replaced. The dowel pipe locates the head and passes fluid. If o-ring is not replaced it will leak the fluid.
If you have the head off it needs to be inspected for cracks. I don’t know about your particular tractor but the smaller thermosiphon engines often have cracked heads from being run hot .
One way to see if it is a head gasket is to have the radiator cap off and start it from the cold engine condition. Then see if you can see any tiny bubbles in the radiator. I am not 100% sure this works for thermostat engines though.
The head is easy enough to get off but the recommendations are to only use the Kubota head gasket not aftermarket one. There is also (probably) a o-ring that seals around a “dowel pipe “ that must be replaced. The dowel pipe locates the head and passes fluid. If o-ring is not replaced it will leak the fluid.
If you have the head off it needs to be inspected for cracks. I don’t know about your particular tractor but the smaller thermosiphon engines often have cracked heads from being run hot .
Russell King
Well-known member
Lifetime Member
Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
I know that the hydraulic pump will generate heat if trying to pump against too much pressure head. So you may want to check that the rear arms are not in the full up position and in pressure bypass which should produce a loud squealing noise.
Smarter people will be able to help you with that. Describe your hydraulic system in more detail if there is anything additional added to the hydraulic system or if just the standard system with only the rear 3PH
Smarter people will be able to help you with that. Describe your hydraulic system in more detail if there is anything additional added to the hydraulic system or if just the standard system with only the rear 3PH
Thanks for the info looks like I have a project!I don’t know exactly what makes the radiator water milky but it could be oil from the engine.
One way to see if it is a head gasket is to have the radiator cap off and start it from the cold engine condition. Then see if you can see any tiny bubbles in the radiator. I am not 100% sure this works for thermostat engines though.
The head is easy enough to get off but the recommendations are to only use the Kubota head gasket not aftermarket one. There is also (probably) a o-ring that seals around a “dowel pipe “ that must be replaced. The dowel pipe locates the head and passes fluid. If o-ring is not replaced it will leak the fluid.
If you have the head off it needs to be inspected for cracks. I don’t know about your particular tractor but the smaller thermosiphon engines often have cracked heads from being run hot .
I thought the same thing and have been all over they system. I will update as to my findings.I know that the hydraulic pump will generate heat if trying to pump against too much pressure head. So you may want to check that the rear arms are not in the full up position and in pressure bypass which should produce a loud squealing noise.
Smarter people will be able to help you with that. Describe your hydraulic system in more detail if there is anything additional added to the hydraulic system or if just the standard system with only the rear 3PH