Finally, finally got to this after the weather started cooling off and the two hurricanes went away and and and . . .
Removed the radiator - yup, all gunked up, clogged and nasty, couldn't see through about half of it!
Gave it a bath in engine cleaner (spray can) followed up by two cans worth of brake cleaner. Lotsa nasty crud came off, the fins are sparkly clean now. Hosed it off big time - yuck!
Put it all back together, filled the coolant (takes about two cups more than a gallon of 50/50 coolant from WalMart), cranked it up, runs nice and cool. Mowed for a little while until I got chased inside by the mosquitos . . . big ones - big enough to show on radar! Little ones - swarms - I thought they were going to eat me alive and then carry the tractor off into the woods and have it for dessert. Tractor SEEMS to be OK, I'll know better after county mosquito control does a helicopter fly-by and I can go outside and play again.
Comments on R&R radiator - easy job, three hose clamps, a dozen or so 10 mm bolts, two 12 mm, disconnect battery negative (just to be safe), access to the lower radiator hose is a lot easier with the exhaust pipe off - a 12 mm bolt on the bottom and a 12 mm clamp on top. A touch of anti-seize on the muffler stub for next time.
Have a drain pan ready for the old anti-freeze, it spatters. About a gallon comes out.
First time, about two hours total, add half an hour for cleanup (me, the tools and the floor), plus 15 minute break for diet coke (the only vice I am still allowed) and cool off in the A/C. Refill radiator and overflow tank, start and run, check level after ten minutes - OK. Will check it again tomorrow when the tractor is cold.
I have a LOT of mowing to catch up on.
Best Regards,
Mike/Florida