Warranty issue dispute with Kubota - Advice anyone

[rScotty]

Any system with a recovery jug will have the top rad tank and upper hose full all the time when operating as designed.

I disagree. It's common practice to design the return portion of any flow system so that the return line has less restriction than the pressure line. The easy way to do that is to make the return line a little larger diameter than the feed line. The goal isn't that you are wanting partial flow in the return line, its just that the simple way to design a inexpensive flow loop is to put a low pressure section into it. Everything becomes simpler then. In the case of a radiator, the upper hose and top tank area are part of the return flow.

There are probably exceptions. At least one manufacturer uses full pressure hydraulics with an accumulator, and for all I know there are some coolant systems that do that in tractors, too. So, I'm not saying that all systems are designed that way, but most are. From what we have already seen in this thread, compact tractor design doesn't attract the same level of thoughtful design that is common in other industries.

Maybe there's a hidden benefit here. After all, folks who buy tractors tend to have a long history of modifying and improving them. The obvious need for a fluid level sensor in a rough country machine like a tractor looks like another opportunity for owners to make them better
rScotty

 

[Chewwy]

I disagree. It's common practice to design the return portion of any flow system so that the return line has less restriction than the pressure line. The easy way to do that is to make the return line a little larger diameter than the feed line. The goal isn't that you are wanting partial flow in the return line, its just that the simple way to design a inexpensive flow loop is to put a low pressure section into it. Everything becomes simpler then. In the case of a radiator, the upper hose and top tank area are part of the return flow.

Having many times observed radiator coolant flow with cap off and engine at idle flow during radiator flushes leads me to believe the upper hose is typically full or nearly so. This was directly observable in some older vehicles where hose return to radiator is observable thru cap opening (both at radiator center). Also my recollection of lower and upper radiator hose is they are usually the same diameter.

Design of engine coolant flow system is very different than hydraulic systems since only work needed is to maintain necessary mass flow rate. Hydraulic systems need to accomplish significant external work in addition to overcoming flow loop restrictions.

For engine coolant system there is no need to specifically design a low pressure section with return line slightly larger. Highest pressure is at pump discharge, lowest at pump suction with pressure gradient in between. Pump must have sufficient head/flow to provide required flow against system pressure drop and maintain pump net positive suction head requirements.

 

[Henro]

I have been following this thread off and on, and admit I don't remember all the details, but do have one question.

I think I remember the OP (or someone else) stating that the operator's manual said to check the coolant level by observing the level in the overflow/reserve tank next to the radiator. I also remember the OP saying the level in this tank was always more or less normal.

If this is the case, how could Kubota deny his claim, if the coolant level did run dry when he followed their procedure?

Perhaps I missed something and they also said to periodically remove the radiator cap when the engine is cold and check fluid level?

Guess I better start checking coolant level in my tractors! Do check the hydraulic and oil levels, but never really the coolant level...always figured I would notice overheating if there was an issue. (did once when my fan belt broke).

Can anyone set me straight on this?

 

[airbiscuit]

I have been following this thread off and on, and admit I don't remember all the details, but do have one question.

I think I remember the OP (or someone else) stating that the operator's manual said to check the coolant level by observing the level in the overflow/reserve tank next to the radiator. I also remember the OP saying the level in this tank was always more or less normal.

If this is the case, how could Kubota deny his claim, if the coolant level did run dry when he followed their procedure?

Perhaps I missed something and they also said to periodically remove the radiator cap when the engine is cold and check fluid level?

Guess I better start checking coolant level in my tractors! Do check the hydraulic and oil levels, but never really the coolant level...always figured I would notice overheating if there was an issue. (did once when my fan belt broke).

Can anyone set me straight on this?

Words in bold explain what didn't happen here.

 

[s219]

Don't know if it would work on every arrangement, but on many cars trucks I have found that by squeezing the upper radiator hose, you will feel/hear the coolant. That is an easy way to verify there is coolant at the high point of the system.

 

[Sawyer Rob]

Don't you guys get it ?, an "idiot light" won't help an "idiot"!!!

CHECK THE FLUID!!

SR

 

[Chewwy]

Don't you guys get it ?, an "idiot light" won't help an "idiot"!!!

CHECK THE FLUID!!

SR

We got that early on, but why miss all the fun arguing about coolant fluid level sensors or what the tractors design should have been or could be.

 

[Henro]

Words in bold explain what didn't happen here.

Maybe so, but still, I seem to be missing something. Did the OP actually follow the operator's manual guidance, and have the issue? OR was it just neglect to do proper fluid checks? And to be aware of how the tractor was acting...

I mean, if a manual told one to check the fluid level by looking at the level in the overflow/reserve tank, and nothing more. And that level did not indicate a problem, would not the owner have a valid beef if problems related to coolant level developed?

Just trying to see the picture clearly, which is a bit blurry for me at the moment...and forever hereafter if no one sets me straight!

 

[ptsg]

There was a previous thread mentioning some issues with the tractor. Those issues being a shutdown and seizing after X amount of time running. Once things cooled down, it would run again.

If that wasn't a indication of something really wrong, I don't know what it is then.

I know I would at least open the hood and check all the basic stuff, like oil, coolant (both overflow and radiator) and air filter.

Then OP insisted running the tractor that way, till it wouldn't run anymore...

 

[ovrszd]

There was a previous thread mentioning some issues with the tractor. Those issues being a shutdown and seizing after X amount of time running. Once things cooled down, it would run again.

If that wasn't a indication of something really wrong, I don't know what it is then.

I know I would at least open the hood and check all the basic stuff, like oil, coolant (both overflow and radiator) and air filter.

Then OP insisted running the tractor that way, till it wouldn't run anymore...

Well stated.