Warranty issue dispute with Kubota - Advice anyone

[RickB]

I had a customer go most of the way down this road with three differences:
The tractor was an L3901.
The radiator bottom tank had been punctured, not a tube or hose.
By some miracle his engine was undamaged.

He brought it in because it would not regen. There was no consideration given to a warranty claim, but insurance paid for the repair.

 

[Fallon]

And most coolant temp sending units will not react to hot air.

Not disputing that, but it doesnt make much sense to me. Temp senders are just resistors that vary their resistance based on tempature. It shouldn't matter if it's in liquid or air. Liquid transfers heat way more efficiently so I could see it reading if the temp sender was being cooled by the outside of the engine or something & the hot air couldnt heat it up fast enough. I'd assume there wouldnt be enough cooling to drop the sender that much though.

My inner nerd wants to understsnd why it doesn't behave like I think it should.

 

[3930dave]

Not disputing that, but it doesnt make much sense to me. Temp senders are just resistors that vary their resistance based on tempature. It shouldn't matter if it's in liquid or air. Liquid transfers heat way more efficiently so I could see it reading if the temp sender was being cooled by the outside of the engine or something & the hot air couldnt heat it up fast enough. I'd assume there wouldnt be enough cooling to drop the sender that much though.

My inner nerd wants to understsnd why it doesn't behave like I think it should.

One factor is where exactly the sensor is located on the engine.

With the head @ the top of the cylinder, I'd expect it to heat up quickly, as coolant level drops.... that's why heads warp. If the gauge sensor is at the head (as opposed to low on block) I'd expect it to heat up too. Possibly slower than if in contact with overheated coolant, but still ending up being heat-soaked by the head.

If the gauge sensor gets booted down low on the block (with ECU getting the top sensor placement in the head), then I could see it's reading staying close to the same, until the coolant drops seriously low.

Long way of saying..... I too am puzzled/intrigued by the low gauge readings @ low coolant.....

View attachment coolant_temp.pdf

Rgds, D.

 

[Grateful11]

I like the ones saying, check the radiator before every use. I mean who really does that? Our son has one tractor that's used every single day of the year 30-45 minutes per day moving round bales. I can't imagine him checking it everyday.

 

[airbiscuit]

Maybe at least check the radiator if something seems off about the cooling system.

 

[airbiscuit]

One factor is where exactly the sensor is located on the engine.

With the head @ the top of the cylinder, I'd expect it to heat up quickly, as coolant level drops.... that's why heads warp. If the gauge sensor is at the head (as opposed to low on block) I'd expect it to heat up too. Possibly slower than if in contact with overheated coolant, but still ending up being heat-soaked by the head.

If the gauge sensor gets booted down low on the block (with ECU getting the top sensor placement in the head), then I could see it's reading staying close to the same, until the coolant drops seriously low.

Long way of saying..... I too am puzzled/intrigued by the low gauge readings @ low coolant.....

View attachment 644487

Rgds, D.

Here's the ;location of the sensor.

 

[Grateful11]

Maybe at least check the radiator if something seems off about the cooling system.

Definitely agree.

 

[Jstpssng]

With the wisdom of hindsight, it's too bad that the right people didn't read the OP's post back in December. There are some savvy people here who would have suggested checking coolant et.al. after reading the symptoms given, had they read his post back then.

 

[aczlan]

Here's the ;location of the sensor.

View attachment 644491

Right up top and away from the cylinders such that if you lose coolant, it isn't in a location that will heat up much...

Aaron Z

 

[Diggin It]

Y'all still beatin' up on the OP? How is that helping him?

the other was a newer vehicle with an air-bubble/lock in the system after I changed the coolant).

I had an '89 Cougar where the T-Stat and hose as it entered the block was above the top of the radiator. If you drained and filled the radiator without following the proper procedures or rechecking the levels, you'd get that kind of airlock. Not sure how many Ford products had that system, but I think my Taurus does too.