New Holland T1520 Clunks When Trying to Start

Howdy,

I have a 2010 New Holland T1520 with 420 hours on it. I was using it last week to move firewood. It performed like a champ! Unfortunately, I ran low on diesel fuel, so I added some diesel from a tank I use to heat up my workshop. This diesel was old and had sediment in it. Nevertheless, the tractor started up fine and I was able to continue my work. All of a sudden, it started to bog down, made some rumbling noises inside the engine, and it stalled and it would not restart. I let it set for an hour or so, then came back and started it up again. It started fine, but the rumbling noises continued, so I drove it straight to my workshop. Just as I got to the workshop, it stalled again.

I removed the fuel bowl, which was filled with sediment, and drained the fuel from the tank. I flushed the tank out with some fresh diesel, cleaned off the filter and bowl, and put it back on the tractor. I bled the air out of the tractor and then tried starting it again. When I turned the key all I heard was a click and then clunk sound. I popped the hood, removed the side panels, and tried turning the cooling fan by hand. It was totally seized up!

Next, I crawled under the tractor and got a wrench on the main pulley and tried rotating it back and forth. I got it to move a bit, and then some more. Then I went on top again to turn the fan by hand. It was moving a lot more freely. I turned the key on again and it tried to start this time, but after a second of turning I heard the clunk sound again. I went back under the tractor and tried turning the engine pulley again but this time it was seized stuck.

The battery is good. It is completely charged up. I did change the motor oil and filter. This tractor has the hydrostatic drive on it (which is awesome!). I'm stumped. Any ideas?

show.. welcome to YT! You call it a clunk. Have you
ever heard and engine with a rod bearing knocking? I
would not call it a clunk a better description from my
experience is the knock as if someone is in there with a
hammer pounding nearly as hard as they can. Do you
think what you are hearing could fit such a
description? What does the oil look like is it overfull? Is
the coolant at the correct level? If the oil level is high
pull the drain plug loose and see if coolant drips out. If
it is fairly easy the suggestion in the other forum to pull
the injectors is probably a good idea.

Thanks for the warm welcome old used MN. I found out the answer late this afternoon. I was going to take the starter out to check if it was causing the flywheel to jamb up. While looking over the starter I found a piece of cast metal that came from the lower engine block. Right behind the starter was a two inch sized hole with a rod sticking through it. Time for a new tractor....