D722 with 3800 hours started leaking oil looks like from rear area.
a) what besides the rear oil seal could it be?I would suspect the oil drain hose connection before anything else. Other possibilities are the oil pan to block or possibly the oil could be running down from the back of the valve cover.
b) Is it possible it will fail big time in the next 200 hours? (we are in Greece and prefer to fix in US)Without checking it myself or knowing exactly where this comes from, I can't answer this one.
c) Is it a common failure?No, this is an extremely rare failure
d) what parts besides the seal are required to fix?This depends on whether it is the seal or not. As I said above, the first thing to check is the hose connections for the oil change pump which is at the back of the sump (oil pan). If it is this, it is a simple matter to tighten the fittings but that is said without knowing what your access is like.
I don't have a oil change pump. I have a drain plug and it is not leaking.
The oil pan is a good idea and I will try tweaking all the bolts after the engine cools down. I believe I can get to most of the bolts am rooting for that solution.
The bottom rim of the oil pan is coated with oil but the oil is traveling all over even to the front of the engine. But an experiment (cleaned all surfaces and fresh oil appears in rear on the lowest point of the bell housing) just minutes ago confirmed that the source is in the rear.
The valve cover is a good idea also and will check that when engine cools down.
1) Oil pan bolts all tight, none budged. Still could be leaking but don't understand why the oil pan joint would all of sudden start leaking. BTW: we are taliking about 6-8 oz of oil in 20 engine hours.
2) Valve cover shows no sign of leaking anywhere.
3) FYI: the only engine changes in the last 100 hours has been a change of the raw water pump that had a leaky water seal.
4) What else could it be besides the real oil seal??
One other possibility is that your breather is clogged. This is really the first thing to check. Depending on how old your engine is there are 2 completely different breather systems.
1) The older engines had a tower as part of the valve cover. You need to remove the valve cover to gain access to this and then after removing the valve cover, undo the 2 screws that you will see inside the valve cover. This will allow you access to the breather which can be cleaned with kerosine or gasoline. Reassembly is the reverse of removal and the copper washers and rubber gasket should be wiped clean before you re-use them.
2) the newer tier 4 engines have a serviceable PCV valve which is accessed from the top of the valve cover. Remove the 4 screws and take out the breather and spring. Clean as above and reassemble.
Try this first and wipe up under the engine before testing. Your repair may just be this simple.
I cant post a pdf file on this forum or I would show you the exploded parts diagram.
If this doesn't do the trick then there is not much at the back of the block. The rear seal is fitted into a removable housing so you will need the seal and the two gaskets for the housing. This is a very easy job once you have the flywheel off. The hard part of the job is getting there.
There is only one other leak possibility at the back of the engine but that is extremely doubtful. There is a 1/8"BSP plug at the end of the camshaft oil gallery and you must remove the back plate to see this.
Ok, we have an older model with a steel wool like arragement for the breather. Cleaned it up but was not blocked to start with. I was hoping on the pcv - great hint, thank you.
So, before removing engine for replacemnt of rear seal I am still seaching for other pehaps less probable but easier to fix problems.
Staying on the possible overpressure theme maybe the oil pressure relief valve is not operating correctly because of dirt, etc. To inspect the oil pressure relief valve I need to unbolt the oil filter mounting bolt, after removing the oil filter, is that correct? The way the engine is installed it is a blind operation, maybe some mirror visablity.
Any other thoughts?
thank you, Ray
BTW: I find that the following manual has better pictures than the Kubota workshop manual.
The oil pressure relief valve has no effect on this oil leak. If you have eliminated the oil pan, valve cover and any other obvious external leaks that may run along the block and then down I am afraid that this is the time to move the engine to where you can work on it. Make sure that you have the new parts before you start the job as you dont want to find that you have a week to wait for them when the engine is in the middle of the salon.
The newest Kubota manuals have good photos as well. Much better than the old ones.
Stanley
The leak turned out to be the oil pressure switch body. Probably the internal rubber gasket failed. It was tough to find since we have a second house alternator that restricts visual access to the switch and an oil ooze is tough to spot. The oil switch is mounted high and the oil traveled all along both sides of the engine following the oil pan rim and onto the bell housing.
Thank you for all your help. I will email you for parts order.
