BX1800 burning oil and poor HP

[majorwoodard]

My Kubota BX1800 got too hot at one point, burning a hole in the top of the radiator and melting part of the oil fill cap. Now that I have replaced the radiator ($515) and changed the oil and filters, it runs but burns a lot of blue smoke and almost stalls when operating the belly mower. Anyone have a good idea of what else is wrong with it? I am tending to think that the valves or the piston rings are now shot, but I don't know that much about diesel engines. It has almost 1500 hours on the engine.

 

[I802Cool]

I'm not a small engine mechanic but this is not rocket science. Sure looks like piston rings, oil scraper and compression rings shot. You could have exh valve issues as well, valves not seating due to burned seats or valve sticking in the guide. I don't know if this is a non-interference combustion chamber. Quite a few variables. The motor oil perhaps got so hot the viscosity dropped too low. Motor oil will also "coke" at extreme temps and leave hard deposits, which could jam the rings in the grooves and lead to metal to metal contact, liner scuffing. End of day, take her to a Kubota servcice center.

 

[pedalstomper78]

Actually, when an engine gets too hot, clearances shrink. Here's the problem with that. When you've got a piston that's the same size as the cylinder instead of a few thousands smaller, you get wear. "Rings" don't really get shot. What happens is that the cylinders usually get out of round making it so that the rings can't seal correctly.

I don't want to say "toss parts at it" though. Run a compression test on the engine. It should be as simple as turning the engine over with the starter (fuel shut off) with a compression tester in the glow plug hole. You'll spend some time with this, but that will give you a good idea as to the overall condition of the cylinders. Once you have tested it, put a few squirts of oil in each cylinder. If the compression comes up dramatically, there is a ring sealing issue. Keep us posted!!!

 

[pdowling1]

If it got hot enough to melt the "710" cap, I would bet the motor suffered extreme damage. With 1500 hours, and severe overheating, I would look into replacement of the engine. You likely have a cracked, or at least warped head, damaged pistons, who knows what else. Good luck, and I hope I am wrong.

 

[I802Cool]

Major: Based on feedback here this is water over the dam but I'm curious about the "getting too hot" part. Melted radiator is likely coolant loss, don't see anything else causing that. Leaky hose? Head gasket leaking? Bad luck in any case.

 

[majorwoodard]

Thank you all for your replies. I think it is far beyond my capabilities to repair it, so I think I will either keep running it until it dies or take my loss and try to use it as a trade-in for a newer one. It still runs OK (smooth even), just smokes and doesn't have near the power it used to. The vent hose out the top of the valve cover spits out a lot of oil (probably two drops per second) when it is running also. The new radiator keeps it cool, -temp gauge doesn't get above the halfway mark after 20 minutes of mowing.
Irregardless, I am leaning toward replacing the whole thing rather than repairing the engine. I've been wanting one with a loader and back-hoe anyway...
thanks again
Ron
Hot Springs, AR

 

[Don87]

I wouldn't wait too long on the 'trade-in'.............I honestly don't expect that engine to last long at all.

I'm surprised it's still running.

 

[Leejohn]

1802cool
What is non-interference combustion chamber, never heard of that before.

Ron if the engine is running like you said, I would not run it anymore. The engine can be saved right now, but well not be with much more running. I would say right now all it needs are rings and maybe a new or used head.

 

[Don87]

1802cool
What is non-interference combustion chamber, never heard of that before.

Ron if the engine is running like you said, I would not run it anymore. The engine can be saved right now, but well not be with much more running. I would say right now all it needs are rings and maybe a new or used head.

To make that engine right, with the amount of heat it generated..........about the only thing salvageable is the block. Maybe the crankshaft if you can get it turned and get oversized bearings.

 

[Mace Canute]

Overheating an engine can cause all sorts of problems the severity of which depend on a few factors such as the obvious ones of how hot it actually got and how long it was ran like that and even the make of engine...some are tougher than others. From what you have said, I believe your best bet would be to trade it in ASAP. It will only get worse as you run it, and if it is salvageable now, continued use might push it past the point of no return and lower what ever trade in value it has at present.