Hi all , I recently purchased a D47u serial no 34357 from pictures only , bit of a risk I know but was after the running gear for my other dozer. It was explained that it had a blown head gasket.. no biggie and it was cheaper than a set of tracks. Long story short when I went to see if I could get it running enough to get aboard a transporter it had nipped up, I filled the air intake and exhaust with kero/ oil mix , got a bar on the ring gear and rocked it free, then once I had the pony motor running left her spinning for 10 min on full throttle decompressor on , as I through in the start lever she started pushing the coolant out the Radiator (filler Cap was off ) not just bubbling but great surges of coolant, got her running , topped off the coolant and ran it straight onto the transporter, then shut down , this level of blow by into the water jacket was excessive should I be examining the pre combustion chambers for leaks since there is not much sign of a serious gasket failure once I got the head off?. 

Yes have a look at them. They are not hard to get out with the correct tools. My 6U had one rusted out and i wasn’t sure what i was going to do with the tractor because i bought it just for the hydraulic blade setup. I welded it up with the mig welder over 12 years ago and it is still working fine. I don’t think they are very expensive but it was a six hour round trip to get a new one from a dealer.