I run sleds (no suprise when your from minnesota) and we/i at the start of the season will go through the sleds and give them a good once over before the season - A trick I learned to check seals, base and head gaskets was to use a compressor to blow air on the PTO seal (they like to go) bease and head gasket areas and listen for the engine to idle up. If it did replace what ever was leaking before you got stranded at -40 and 2 am in the middle of some state forest. Tried it tonight before taring down the top-end. Just an idea.