Kubota Radiator Cap Danger...

[Al Barrs]

If you have an older Kubota tractor check the radiator cap. If the rubber gasket is worn or frayed REPLACE it!

I own several Kubotas but on my G1800-S garden tractor w/mower attachment this morning the soldered radiator coolant filler soldered to the top of the radiator blew off and scalded both legs and my left arm. Upon investigating what went wrong and why the pressurized water didn't flow into the over-flow tank and then to the ground as it should and had before on occasion. Instead and apparently the radiator filler fitting soldered to the top of the radiator blew off and the expelled water scalded my legs and arm. Upon investigating why the overflow hot water didn't exited to ground I discovered all water lines were open. First I thought a dirt-dobber might have built a nest in the exit water tube but both exit tubes were open. I then discovered that the radiator cap's rubber gasket was frayed and had no doubt stuck and prevented the water pressure from activating the relief valve in the radiator cap which prevented the hot water from exiting into the overflow tank and then to the ground. I urge all, whether Kubota owners or other tractor owners to check your radiator cap and make sure it is in perfect operating condition... Don't let a few dollars stand in your way of avoiding great pain and suffering... Good Luck! I hope this helps and prevents further accidents...

 

[stevewarner1957]

Thanks for the post Al, I will check mine in the AM.

 

[diesel85]

I replace all my radiator caps at 10 years. Cars, trucks, motorcycles, tractors, etc... they are cheap!

 

[ganeydn]

This happened to my B8200 this morning. There was steam coming from the overflow tube, whistling, on and off as I was doing heavy work, and then all of a sudden, steam was coming out from under the hood in large clouds. When the air cleared and I opened the hood, a silver ring of solder was showing where the filler neck was supposed to be.

What can I do to get this fixed short of a new radiator?

Thanks

If you have an older Kubota tractor check the radiator cap. If the rubber gasket is worn or frayed REPLACE it!

I own several Kubotas but on my G1800-S garden tractor w/mower attachment this morning the soldered radiator coolant filler soldered to the top of the radiator blew off and scalded both legs and my left arm. Upon investigating what went wrong and why the pressurized water didn't flow into the over-flow tank and then to the ground as it should and had before on occasion. Instead and apparently the radiator filler fitting soldered to the top of the radiator blew off and the expelled water scalded my legs and arm. Upon investigating why the overflow hot water didn't exited to ground I discovered all water lines were open. First I thought a dirt-dobber might have built a nest in the exit water tube but both exit tubes were open. I then discovered that the radiator cap's rubber gasket was frayed and had no doubt stuck and prevented the water pressure from activating the relief valve in the radiator cap which prevented the hot water from exiting into the overflow tank and then to the ground. I urge all, whether Kubota owners or other tractor owners to check your radiator cap and make sure it is in perfect operating condition... Don't let a few dollars stand in your way of avoiding great pain and suffering... Good Luck! I hope this helps and prevents further accidents...

 

[Jim Nelson]

Most radiator shops can replace the neck pretty easily.

 

[Oldpath05]

Sounds like one of things that no one ever heard of..... I thought a radiator builds up a little pressure then stays there unless there's a severe engine problem. I'm not even sure why a radiator builds up pressure in the first place.

I only changed my coolant once in 12 years on my tractor when it became 4 years old, then 3 years ago it was down a little and only noticed that because of the temp gauge, maybe it's time to do a radiator check, something that I dont think is hardly mention on this forum.

 

[mrmikey]

I'm not even sure why a radiator builds up pressure in the first place.

If you mean what causes it, it's the water getting hot and expanding as well as creating steam.
If you mean what is the purpose, water under pressure boils at a higher temperature than water at atmospheric pressure. Ever wonder why coffee in an airplane is never as hot as what you make at home, lower pressure in an airplane therefore water boils at a lower pressure i.e....colder coffee......Mike

 

[ganeydn]

Most radiator shops can replace the neck pretty easily.

Thanks, Jim. Now: how to get the radiator out without spilling antifreeze on the field I was tilling.

 

[4570Man]

If you mean what causes it, it's the water getting hot and expanding as well as creating steam.
If you mean what is the purpose, water under pressure boils at a higher temperature than water at atmospheric pressure. Ever wonder why coffee in an airplane is never as hot as what you make at home, lower pressure in an airplane therefore water boils at a lower pressure i.e....colder coffee......Mike

Who heats coffee to the boiling point? And shouldn’t the radiator not be hot enough to boil either?

 

[repete]

If you mean what causes it, it's the water getting hot and expanding as well as creating steam.
If you mean what is the purpose, water under pressure boils at a higher temperature than water at atmospheric pressure. Ever wonder why coffee in an airplane is never as hot as what you make at home, lower pressure in an airplane therefore water boils at a lower pressure i.e....colder coffee......Mike

Good response Mike. It is important to develop this pressure as it, in combination with the proper coolant does raise the boiling temperature. This causes the coolant, as it contacts the cylinder head, to stay in contact as opposed to "vaporizing" as it hits the higher temperature at this location and consequently a better heat transfer occurs.