Trying to help a neighbor with her 1980's 755 that's overheating. Think I've narrowed it down to the thermostat. Owners manual says take it to the dealer for the replacement. Before I put a wrench on someone else's tractor I would like to know, is it as easy as removing the hose elbow on top of the block and swapping out the thermostat? I would have thought it would be in the manual if it was that simple.