Is it not possible to drop the sump on a M4500DT to inspect the bottom end bearings, without removing the entire engine from the tractor?
M4500DT Inspect bottom end
- Thread starter Fishfarmer
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rbargeron
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Equipment
L5450, L48, L3250, L345 never enough attachments
On Kubota tractors the oil pan is a structural part of the chassis so taking it off is a major teardown. And with the oil pan off only the con rod caps can be accessed . The mains are inside circular holders that all come out one end with the crank. (typical block pic attached) That said it is also true that bearing failures are pretty rare in Kubota Engines.
What symptoms does your M4500 engine have?
What symptoms does your M4500 engine have?
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Thanks rbargeron, and the photo is helpful. My other threads go in to detail of the problem.
I always thought I have rod knock, but other replies have suggested its possible injector nailing.
From my experience with cars, the sound seems deep in the engine but i cannot locate where it is listening with a dowel or screwdriver. It doesn't seem low down but not sure. Rockers are noisy, some bushes are worn and tappets clatter. This other sound is different. Further diagnosis, i did injector bench test and most sprayed at correct pressure with one slightly spraying some off to the side. IP seems to spurt evenly with injectors removed. Rotated injectors. Further symptoms, compression test down on one cylinder#6, others about 350psi with #6 at 250 psi, it goes to 350psi with squirt of oil. Suspect worn or broken rings with this. If it was only this I would run it for longer but maybe worn or bad bearing also, if it is this then eventually catastrophic failure. Oil pressure good at 60 psi cold then goes way down to 20 when hot( 10 psi on idle). Hard quick rev it goes up to 40 psi. No oil flecks in old oil after change, using 15w 40 good quality oil but am thinking of using heavier oil to raise oil pressure, but I don't think this will help if it is rod knock . Advised to get mechanic in to try to diagnose positively what the knock is. Please read my other threads I describe tests and symptoms which will give you a much better idea, thanks.
Not at hot idle, hot running (medium throttle). Very old tractor 1978-1980.
Manual says 45psi with allowable limit 35psi at "rated speed" whatever that means.
All I can find in the manual is "Maximum Bare Speed" in a different section which is 2800 rpm
rbargeron
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Lifetime Member
Equipment
L5450, L48, L3250, L345 never enough attachments
Might be helpful to have an experienced diesel mechanic (equipment and trucks) listen to it. If possible get more than one opinion. Can you trailer it ?
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Not really, I will have to pay someone to come out. The problem is finding a mechanic who knows what he is doing from experience, than someone who things he knows and educated guessing.
I know a couple of mechanics and get a few independent opinions. I think the combined symptoms of low compression in one cylinder,/blow-back/low oil pressure at temperature/ engine knock/ is telling me rebuild. Only superman with x-ray vision could give positive diagnosis without strip-down. I am going to remove the front end and drop the sump to inspect the rod bearing. It seems like it can be done without too much trouble. If it cant the front end has to be removed anyway and I can take out the engine. If its a rod bearing I am only going to see catastrophic failure if i don't do something about this. There are complete Chinese kits for these on the cheap, but they seem too cheap to be good quality. I can look for another engine over here but they are like hens teeth. Any help with parts I appreciate but I live in Australia.
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