frig cooling problem...with a Norcold 821

Dougrainer, thank you for your comments. This class C rv was bought brand new in 099! May be we parked it off level a bit in truck stops, when we stopped for lunch , but level enough to cook on the store! I will take it off and bring it in the basement and rotate it a lots of times for a couple of weeks! If it is not correct, would you advice me to buy a "cooling unit"and change it yourself or would you just replace the complete frig for the" 841" IN québec I can buy a 841, witch replaces the "821" for about $2200.00cdn. For the last 9 years we camped on the "Bonaventure river" in the "wild" the average rate of propane is around 1 liter a day to keep the frig cold and this did not change much from years to years Before anything, I will do what you suggest me to run on bypass ac ,but I don't.suspect a heating problem. Up to 3 years ago we used to run it cooler with a lot of food in it .The fins would freeze very fast , so we had to unfreeze it(turning it off) every 2 weeks, then we realised that by making it run a bit less cool, there was no ice buildup on the "cooling fins) so no need to "unfreeze it" , and the foods were still perfect. From your experience, what is the normal life time of a frig that runs around 90 days a year. From Rimouski ,-27C outside ! Ronald.