L4350 fuel in Oil

[Greg82]

Hi All,

I've got a Kubota L4350 and it's got diesel in the oil. Initially, I thought the problem was the lift pump so I replaced that. Unfortunately, the problem still exists, now I'm looking at the injectors. I'm wondering if there's an easy way to test which injector(s) are leaking?

If not I guess I need to just replace all of them? any other possible causes?

Thanks for the help

 

[Russell King]

Are you 100% sure it is fuel and not hydraulic fluid from the pump seal leaking?

No idea on checking how to identify the leaking injector if that is the culprit.

 

[Greg82]

Are you 100% sure it is fuel and not hydraulic fluid from the pump seal leaking?

No idea on checking how to identify the leaking injector if that is the culprit.

hmm no I’m not sure, I’ll spend some time smelling the fluid to see if I can determine which it is.

Where’s the pump seal located?

 

[Russell King]

hmm no I’m not sure, I’ll spend some time smelling the fluid to see if I can determine which it is.

Where’s the pump seal located?

You may be able to drain some of the oil into a glass jar and let it sit for a day and see if it separates at all. I ASSUME that the diesel would separate out and the hydraulic fluid would not but you need to search information on that. Your nose is probably the best indicator.

There are a couple of different pump options for the L4350 so you may need to look at the illustrated parts list but one for the L4350 tractor has the seal on the end of the shaft that is at the flange mounting face which should bolt to the engine. The pump shaft extends into the engine block and is driven by a mechanism in the block. If the seal leaks the hydraulic fluid drains into the engine oil.

You may check the level of the hydraulic fluid but unless it has leaked a lot then the level won’t show low since there is so much fluid in the transmission case (gallons)

 

[Greg82]

Thanks for the info Rusell I appreciate the help.

I don't have a part list, are they available online? If it is the pump seal it sounds like a big project to change it.

 

[Russell King]

In the USA the illustrated parts list is available at Kubota USA dot com or Messicks or Coleman’s sites. I don’t know if you can access the Kubota site but there is probably a Canadian version.

Changing the seat is pretty easy if you can get to the pump easily. My old L185 is really easy to work on so I kind of think all tractors are easy to work on.

 

[GeoHorn]

If you don’t already…. using dyed diesel may reveal if it’s fuel…. OR… auto part stores sell UV additive kits which can be used to determine where or what is leaking by using the kit-contained pen-light.

 

[Greg82]

Thanks for the idea GeoHorn, I might do that.

Found parts diagrams on Kubota Canada so that helps a lot.

I'll take a look at the tractor later today and post back thoughts.

 

[Greg82]

Ok I’m now leaning towards hydraulic fluid. Is this the pump in the picture

 

[Greg82]

Here’s a better picture. So I just unbolt the 4 bolts?

I’m going to look at the parts diagram now

 

[Greg82]

here's the part diagram, are we talking about number 110?

Really appreciate the help

 

[Pau7220]

here's the part diagram, are we talking about number 110?

Really appreciate the help
View attachment 89434

No…. You need to go to the component parts breakdown. #30 is the pump shaft pressure seal. Watch the snap ring orientation when you pull it, they only go one way.

 

[Russell King]

@Pau7220 would you confirm that seal leaking would get into the engine oil (crankcase)?

On that tractor picture it looks connected to the injection pump so I have no idea.

 

[Russell King]

Here’s a better picture. So I just unbolt the 4 bolts?

I’m going to look at the parts diagram now

You will also have to remove the bolts attaching the inlet and outlet pipes into the pump and probably should replace o rings underneath those pipes.

Try to get confirmation that the seal leaking will flood the engine crankcase before tearing into this.

Clean the exterior of the pump before you remove anything since it seems fairly dirty.

When working on the pump itself try to work on a clean surface like kraft paper and keep the inside of the pump clean as possible. You may want to get a quart of hydraulic fluid to use to lube parts as you go back together.

If you remove covers with o ring seals I would replace the o ring while you have it apart. It doesn’t look like you really even get into the main body of the pump.

 

[Pau7220]

@Pau7220 would you confirm that seal leaking would get into the engine oil (crankcase)?

On that tractor picture it looks connected to the injection pump so I have no idea.

That offset gearbox along with the injection pump cam are all lubed with engine oil, so yes.

3 of those seals in stock says a lot .

Greg, follow Russell’s advice in post #14 for a clean, complete job.

 

[Russell King]

Deleted
Got the answer above while posting

 

[Greg82]

Update, I followed the advice in this thread and was able to change the pump seal over the weekend It wasn't very hard at all.

After changing the seal I drained the engine oil and refilled it with new oil, so far the level has stayed the same but I haven't run the tractor very hard... .so time will tell.

Thanks for the help everyone.

 

[Russell King]

Glad you got it working again. Please post back after a few hours to confirm that the seal did resolve the issue completely (which I think it will)

 

[Pau7220]

Good deal.
Thanks for the update.

 

[Greg82]

Thought I would post an update and let everyone know that so far the oil level is good.

Thanks again for the help