Reply to RossM:
Thanks for the info guys
I've used that rubberised cork sheet on my old girls radiator tanks and it has worked well, available at any bearing shop or Repco Store, get your new bolts and washers from your local Cat dealer, they have the best quality at the best price, either black or zinc yellow, sing out if you need the part numbers for the bolts as there are a couple of different lengths used on those radiators, with the thermostats I measured the old one and got on Google to search out a Aussie thermostat website (Dayco??) which lists all the sizes shapes and opening temps, aim for about 170F or 175F on that 22, and get your local store to order it in, the cost was about $35, you can buy them in the USA for about $US7.00-$US9.00 if you check out Fleabay.
I've bought thermostats from my Cat Dealer here though be aware the temp range might be a bit too high for your 22 running on petrol, OK for the diesels at 185F or 190F, I think the idea of a sleeve to carry a modern thermostat is a good one, double check your parts number book on the thermostat as there were several different one's used, if you don't have a Parts Number book yet tell us your tractor serial number or better still the type of upper water manifold you have that goes into the top tank of your radiator, some have a cap at the motor end, the other type does not.
There are a lot of 22's around Oz and many on here have repaired them, so ask questions if needed.
Mike