correcto o wise one. Pull the rubber hoses off the cooler. They are due for replacement. Place a bolt in the hose ends and hose clamp to prevent water leak. Run the eng and look for stream of oil after it warms up. I have seen very few heads which have been as hot as you say that didn't crack around the copper inj. tubes. Have it pressure checked by someone with an AC kit. Trick we learned is to put a little soap and red dye and water in head before pressurizing then pump her up and turn the head all angles..look for red H20. If cracked don't let anyone "Plug" it. Take it to someplace who heats the head then welds and it will hold. Have someone who has put in cummins type copper sleeves with an AC kit to install sleeves. As to blue smoke that makes me think gaulded piston(s)... A good winter time project. Piston_sleeve_brg_gasket kit not that bad of price through AGCO. Make sure if you have bosch injectors you switch tips to smaller hole if you have the low compression pistons as what you get will be higher comp ratio. There are bulletins to yeah verily glide you through the valley of updates. Ask if you have any questions and will need eng sn. to answer specifics. Good luck.