Kubota diesel and greatly extended OCI

[oil pan 4]

I think I found the breaking point for not changing the oil in a Kubota diesel.

I got a flood light set with a 3cyl 905cc Kubota diesel from about 2003.
4981hrs, almost brand new.
Last oil change April of 2023, 2342hrs on it, was just too much. It was running like it was firing on 2 cylinders, tested the injectors and pumps, the amount of fuel and spray pattern looks normal. It would appear one cylinder has low compression.
I've found ones that have gone 4 to 7 years with 300 to 800hrs on an oil change no problem.

 

[cptbarkey]

That is low hours for a work light, sounds like it was overheated.

 

[burbguy82]

That is low hours for a work light, sounds like it was overheated.

with 2500 hours on the oil change?

 

[Plumb Bob]

2342hrs on it

Probably too much. What oil?

 

[cptbarkey]

with 2500 hours on the oil change?

let’s assume he is right. No mention of sludge is sketchy. My bet would still be it was overheated.

 

[oil pan 4]

Probably too much. What oil?

Probably safetykleen 15w-40.

 

[oil pan 4]

let’s assume he is right. No mention of sludge is sketchy. My bet would still be it was overheated.

No sludge, they may have changed the oil only but I doubt it. It has a pretty good oil leak where the fuel shutoff solenoid goes on the engine so it changed it's self. It was written up last year for needed an oil filter because they couldn't get oil filters, because they didn't try. It's a 3/4-16 thread oil filter, the most common on earth.

 

[oil pan 4]

Update: I think I saved it.
No forbidden glitter in the oil or oil filter.
I pulled injectors last night to do a compression test with my compression tester. Left it over night with a squirt of synthetic PAO+ester hydraulic fluid in each cylinder.
Today tuns out I do not have a Kubota compression tester for injector or glow plug.
So I put it back together and it appears to be running normally. The real test will be to turn on the lights and plug my car into it putting an additional 240v 16 amp load on it.
It sounds like it's firing on all 3 cylinders with no load and lights only.
Didn't drive my car today, will load test tomorrow.

That is low hours for a work light, sounds like it was overheated.

I've seen them ran with the radiator packed full of dead bugs with all the coolant boiled off and they still ran fine.
The low coolant shut off mysteriously became unhooked on those lights.
I thought for sure that was going to be 4 engine changes.
Those 905cc engines may be unkillable.

Oil filter pics.
Napa 1332 with 2342hrs.

 

[cptbarkey]

Perhaps the injection pump was clogged and you cleared it.

I had to buy a supplemental compression tester too for Kubotas, but I went through glow plugs vs injectors which was easier. Here it is if you need in the future.

https://a.co/d/d8eQJnW

 

[oil pan 4]

I think this is a better pic of the oil filter.
No forbidden glitter makes me think stuck rings.

I looks like the 800hr filter off one of these engines.

 

[oil pan 4]

Perhaps the injection pump was clogged and you cleared it.

I had to buy a supplemental compression tester too for Kubotas, but I went through glow plugs vs injectors which was easier. Here it is if you need in the future.

https://a.co/d/d8eQJnW

Yeah I had the injectors pulled to test them and it appeared that I had tester that would go in the injector hole.
The one I had was the same thread pitch but 1mm smaller.
Glow plug adapter testers I had weren't even close.

 

[oil pan 4]

I found another one today. Had about 990hrs on the last oil change.
Didn't do anything to it other than dump some parts washer juice in with the oil and ran it for a few minutes.

The 2300hr oil change one runs like new. Charges my car with all lights on, purrs like a 900cc kitten.
Oil is nice and black after 3hrs of run time.
Several CCs of synthetic hydraulic fluid in each cylinder did the trick.

Something I've never done before is check the oil run temperature in these engines. The coolant only runs at 140 to 160f. They only get over 180f when over 90f air temperature, lights on and charging my car for extended time, when I "forget" it's charging and leave it running for 2 or 3 hours. Oops....
I'll bring my probe thermometer Monday. I'll bet the oil runs cool with just the lights on.

 

[38Chevy454]

Just for a fun calculation, the 2342 hours, if in a car with avg speed of say 40 mph over that time, is like 93,680 miles on an oil change.

 

[oil pan 4]

The oil in these little engines only gets as hot has the coolant.
Ran one for an hour and a half with the lights on and charging my car and it only ever got up to 160f.
Normal temperature range running the lights only is more like 120f to 145f.
Likely the main reason they can run for thousands of hours and not sludge out the oil.