I need a komatsu expert

I got a d20p-5 love this little dozer. It was putting exhaust in the cooling system so I pulled the sleeves. I am trying to find a rebuild kit but my local komatsu dealer says I have to order every part separate. When I pulled up the sleeves on the part imager it shows two different number, but doesn't give any explanation of the difference. I just want to get a kit and put this thing back together. Aftermarket or oem I don't care. Can someone please send me in the right direction. Thanks

I need a komatsu expert