Kubota 3350b Regen DPF Issues SOLUTION!

[joelx777]

I have had tons of issues with the terrible DPF system on my Kubota 3350b. The Regen light would come on and would not go off. Eventually it would demand parked regen. That would fail too and it would beep once a second until I took it to the dealer.

I noticed this did not happen in the summer, just in the winter and spring and fall. The dealer said that when he was testing it, it was not getting hot enough. I suggested putting a blanket on it, he ignored that.

I started having the issue again this week. I went through the process of failed automatic Regen, failed parked regen, and finally tried my blanket idea.

With one heavy moving blanket covering the whole engine and radiator but not the exhaust, the temperature never went above three bars. With two blankets, I was able to get it to 4 bars. With three blankets, I got it to 6 bars and successfully ran the Regen and the errors are all cleared now.

I guess the engine just is too cold by default to run the Regen.

https://joelx.com/kubota-3350b-regen-dpf-issues-solution/17912/

 

[heymccall]

Sounds like a bad engine thermostat.

 

[joelx777]

Sounds like a bad engine thermostat.

The thermostat shows changes in heat... 0 bars all the way through six. Or is this thermostat a different one? Also, when I put my hand up under the blankets near the radiator, it was not even all that hot.

 

[Vetech63]

I hope those blankets are fireproof.

 

[Tinkerer]

https://denresidence.com/kubota-b3350-problems/

 

[joe--h]

Tinkerer, did you read that site you posted?

It's nonsense.

Joe H

 

[joelx777]

Tinkerer, did you read that site you posted?

It's nonsense.

Joe H

It's an AI generated SEO spam site, the profile is probably a spammer posting links to generate SEO value.

 

[joelx777]

I hope those blankets are fireproof.

Not really haha.

Also, I ran into a new problem.... My right front tire by the exhaust is flat. There is not physical damage, but it looks like the bead retracted all around. I can't refill it, air just flows out from under the bead. Heat damage? I was putting my hand under there and it never felt that hot... But it's the only explanation I can think of.

 

[hosspuller]

The thermostat shows changes in heat... 0 bars all the way through six. Or is this thermostat a different one? Also, when I put my hand up under the blankets near the radiator, it was not even all that hot.

Joel. You're referring to the temperature indicator. Heymcall is speaking about the thermostat that controls the coolant flow to the radiator. If it fails open (which it appears to be) the engine doesn't get to operating temperatures quickly enough.

 

[joelx777]

Joel. You're referring to the temperature indicator. Heymcall is speaking about the thermostat that controls the coolant flow to the radiator. If it fails open (which it appears to be) the engine doesn't get to operating temperatures quickly enough.

Thank you for the clarification @hosspuller and the suggestion @heymccall!

Is this something a relative newbie could try to troubleshoot and fix or should I take it to the dealer?

 

[joelx777]

I just spoke with the tech at the dealer and explained all of this to him. He recommended that I run the tractor at max 2500 rpms all the time to lengthen time between regens and to help the passive regens run through better. He said he has one of these kubota 3350's at home, but they are few and far between now.

 

[heymccall]

To change the thermostat on the engine, drain the coolant to a level below the thermostat, then unbolt, remove thermostat and gasket. Replace thermostat and gasket, then refill cooling system.
There are 3 different thermostat listed, depending on engine serial number.

 

[joelx777]

@heymccall Thank you very much!

 

[hosspuller]

To test a thermostat, put in a sauce pan of cold water. The stat should be closed. Then turn on the stove and measure the temperature at which it starts to open and when is fully open.

Might as well as put in a couple of eggs for lunch too.

Edit to add: Likely not even have to remove the hoses. Just remove two bolts, flex the upper hose and pull out the t-stat & gasket. Reverse with new parts. refill coolant and you're done.

 

[hosspuller]

I just spoke with the tech at the dealer and explained all of this to him. He recommended that I run the tractor at max 2500 rpms all the time to lengthen time between regens and to help the passive regens run through better. He said he has one of these kubota 3350's at home, but they are few and far between now.

If this tech was told everything you've posted here, I wouldn't put much stock in his diagnostic abilities.

Please post back what you find about the thermostat.

 

[heymccall]

I think the easier question is, does the machine reach/ operate at working temperature? Typically, around 190°F, which, with 6 bars on temperature gauge, I can only assume would be halfway.

 

[Birken Vogt]

I have had thermostats seemingly test good in the pan of water, but engine was definitely running too cold.

I think in one case, it was stuck open until we disturbed it, and worked normally under test.

I use a thermocouple taped to the engine in a place where it senses true water temperature and insulated from outside air. That way you can do the best kind of test, in situ.

 

[joelx777]

I think the easier question is, does the machine reach/ operate at working temperature? Typically, around 190°F, which, with 6 bars on temperature gauge, I can only assume would be halfway.

Yes, it typically shows 3 bars after running for a few minutes.

 

[joelx777]

I have not forgotten about you guys, thank you once again for all the help. The tractor is running well with no warning lights for the moment (though it has been rougher and slower to start up). My plan is just to work it till it becomes a problem again. Life with three kids and a different business and dozens of projects!

 

[joelx777]

I have had thermostats seemingly test good in the pan of water, but engine was definitely running too cold.

I think in one case, it was stuck open until we disturbed it, and worked normally under test.

I use a thermocouple taped to the engine in a place where it senses true water temperature and insulated from outside air. That way you can do the best kind of test, in situ.

I worked the tractor a few hours this morning, it seemed to get very hot but the dashboard thermostat never changed from 3... It always seems to stay there. I think I will try your thermocouple suggestion.