D 14 cracked head???

I have a D 14 that I'm slowly fixing up. It has been in the family since it was new. For about ten years now, that I can remember anyway, when we'd change the oil we'd get a little antifreeze. not much, but it was some. Dad was never worried about it and thought it was the head gasket leaking a little or coolant leaking past the liners. I  removed the valve cover to set the valve lash about a year ago and noticed quite alot of sludge on the valve cover and valve/ rocker area. I said something to Dad about it and he said that it was always gunked up like that ever since he could remember. "His Dad was the one who bought the tractor new."  I meticously cleaned out all the sludge and reinstalled the cover. Last week I thought I'd remove the cover and take a look. To my surprise it was gunked up pretty good again and I noticed a little "green liquid" puddled here and there. I knew it wasn't good, but was hoping it was maybe just the freeze plugs/ casting hole plugs leaking. I was hoping they had just corroded through or something. I cleaned everything up reall good and started the tractor and let it run with the valve cover off. After it began to warm up a small trickle of antifreeze started between the exh. and intake valves on the two middle cylinders. ....... :(   My ? being, can this be fixed???  How much  $ would one expect if it can be fixed?? Also, what kind of damage has been done with antfreeze leaking this long??? It could have been leaking for years. The tractor was used fairly often and the oil was changed at least twice a year. What are your opinions?

heres a pic of a head  that belzona has kept the water from blowing out the no.3 exhaust port.

Edited by mlpankey - 03 Jun 2010 at 3:26pm

Warm it up and dump some stop leak or water glass in the radiator.

Its hard to do that when you port through to the water jacket steam hole. The belzona works when the uh-oh happens it  is also resistant to methanol if your doing the bump port to turn the air into the cylinders on Siamese intake runners.  I purchase it from Belzona River States 303-D Beltline Place,SW#313 Decatuar AL 35603 office phone number (256) 355 1560  Ps that head picture above I ran it 2.5 pulling seasons before the bottom end of the motor let go with the belzona repair in the no 3 exhaust port. Dover cylinder head a company known in this area for fixing cracked cylinder heads wouldn't attempt to repair it when they saw it . my testimony . It fixes more stuff in my shop than I through away cause it cant

Edited by mlpankey - 03 Jun 2010 at 8:00pm

I'll try replacing the core plugs first and see what happens. It really looks like there's a couple of cracks though. Are the plugs just standard freeze plugs? Is is something a guy can get at the local parts store or do they have to come from a dealer?