I have a 110 with a TD5 in it and the manual calls for 5-30. I would assume that this is recomended for areas where the temperature range varies a good bit. Here in Costa Rica you cannot find 5-30 and most mechanics say for the tropics where the temperature dosnt fluxuate they use staight 40. Any opinions?? I want to do oil change but at 10bucks a quart I want to do whats best for the life of the motor. Also not a newbee , been around for years changed email and forgot old password.