My trusty 1996 John Deere 425AWS with the FT620D engine will require engine work. The engine runs great but has developed engine blow-by and under heavy load the exhaust will belch a little blue smoke. And I occasionally will have to add engine oil. I would like some opinion as to whether to tear the engine down and replace the piston rings, new intake and exhaust valves and a gasket set or buy a short block if available. What would be the approximate cost for parts be to overhaul this engine. Are there other engines available that will directly mount in the JD425 that would be a better option than the FT620D? Any answers will be greatly appreciated. Thank you.
