Kubota L2900 Problem

[mrinehart]

I have a line that comes out of the valve cover that seems to have positive pressure and it seems to have a light oil haze coming out of the line, why is there a light oil haze coming out of this line that has positive pressure? Is this possibly a bad PCV valve? Tractor got hot a couple months ago from a sticky thermostat

 

[mrinehart]

All of the smoke is coming from the pushrod holes.

 

[North Idaho Wolfman]

You have blow-by, there is only one fix for that, rebuild, specifically re-ring as that is where the problem is originating.

 

[mrinehart]

I am assuming this is not a homeowners jobh

 

[ShaunRH]

I am assuming this is not a homeowners jobh

I wouldn't do it unless you are comfortable taking apart the Head and oil pan. New rings aren't all that pricey, it's the labor that brings up the cost. It will buy you some more hours on the motor, but eventually the motor will need an entire rebuild.

Most old iron tractor jocks just opt to do an 'in frame' rebuild of the engine and a good mechanic can get it done in about a week, less if he has all the machining equipment there in his shop. Then again, you can also just get a rebuilt motor for about the same cost and send the rebuilder your engine back.

There are a lot of options including ignoring it and dealing with the oil in some fashion, but that isn't recommended.

It's what diesel engines do when they get old and need refreshing...

 

[whitetiger]

If it was over heated at least one cylinder bore and piston are scored. Very common problem with any diesel engine. Very few can be repaired without removing the engine and disassembling it as the block has to be either bored out and sleeved back to standard or over sized pistons and rings installed. If bored over size and left, all cylinders MUST be bored to the same size.
It is not a job for the average home owner and darn sure not for an "old iron tractor jock" what ever that is. Have the job done by the dealer or someone you know you can trust.
Check the fill port on your radiator where the lower cap seal flange is, make sure it is smooth. I find a lot of them to be melted by escaping steam thus the cap will not hold pressure.

 

[ShaunRH]

An "old iron tractor jock" is someone that works with and repairs older tractors. I agree it's not a homeowner level job but I could rebuild an old tractors engine out in the field with it's plow still hitched to it. That was the way it was done back in ancient history before you had to haul the monster to the dealer for everything. Fans of old iron become very proficient in most any repair the tractor needs.

An in frame rebuild is designed to leave the engine on the tractor and pretty much pulls everything else of the front so you can take off the pan and head then install the rebuild kit which handles all the sleeves, pistons, rings, seals and other items. It's up to you if you want to take out the crank and have it ground or not, the kits normally come with new journal and rod bearings and if you have it ground you order the right oversize bearings.

There are plenty of people that are capable of doing this job in their garage, they don't need to take it to a mechanic. It's not rocket science. However, you have to be comfortable with the sheer level of tear down and organization it takes to get an engine down that far, so again, nope, not a DIY quick weekend project unless you are just doing the rings. You also need the tools and some machine shop work if you want to be thorough.

 

[Skip44]

When the engine on my L2900 went it was cheaper to get a new one than rebuild the old one. It took less time and the new one came with a warranty. Plus I got to keep the old one and I plan on learning how to rebuild it myself. I have done a lot of gas engines but never a diesel.

Skip

Do you check the compression the same as on a gas engine?

 

[whitetiger]

An "old iron tractor jock" is someone that works with and repairs older tractors. I agree it's not a homeowner level job but I could rebuild an old tractors engine out in the field with it's plow still hitched to it. That was the way it was done back in ancient history before you had to haul the monster to the dealer for everything. Fans of old iron become very proficient in most any repair the tractor needs.

An in frame rebuild is designed to leave the engine on the tractor and pretty much pulls everything else of the front so you can take off the pan and head then install the rebuild kit which handles all the sleeves, pistons, rings, seals and other items. It's up to you if you want to take out the crank and have it ground or not, the kits normally come with new journal and rod bearings and if you have it ground you order the right oversize bearings.

There are plenty of people that are capable of doing this job in their garage, they don't need to take it to a mechanic. It's not rocket science. However, you have to be comfortable with the sheer level of tear down and organization it takes to get an engine down that far, so again, nope, not a DIY quick weekend project unless you are just doing the rings. You also need the tools and some machine shop work if you want to be thorough.

"old iron tractor jock" googled the term, your post is all that comes up. Hmmmm.

Many of us could over haul an old tractor engine in the field with the plow still attached, but what about all the dirt and debris that is blowing around and coating everything? Makes no sense at all to cobble it up and expect it to last, it won't. I have been servicing / repairing tractors both old and new for 40 years now. I have overhauled several hundred engines from a single cylinder to over 1000 CID V-8 and I-6 diesels.

Some engines can be rebuilt in frame, depending on the engine and the failure. A Kubota engine that has been overheated can not! It is a parent bore engine which means it has no sleeve's. Pretty much rules out an in frame! They have to be bored over size. Maybe an "old iron tractor jock" would bore on with a hand grinder and some emery paper.

There is no overhaul kit for a Kubota engine either. You also can not replace the main inserts without removing the crankshaft. The crankshaft and supports come out the rear of the block.

There are several people on this site that are capable of rebuilding their own engine, many have.

What parts are you removing from the front of the engine during an in frame overhaul????????

The original poster is asking about his L2900 Kubota tractor engine, it is a grave disservice to not be accurate and give incorrect advice.

 

[ShaunRH]

I'm sorry that it has devolved into some kind of bizarre misunderstanding over words and concepts that Google doesn't know. So, I'll concede Whitetiger, you win. My advice is inaccurate and incorrect.

Mrinehart, please take your tractor to the dealership. They can fix it for you. I apologize for my misleading you with my silly arrogant banter.