• When you change the oil in your 2003 Polaris Snowmobile, it is generally best to follow the instructions presented by the owner's manual or the advice of your dealer when it comes to the brand or type of oil your vehicle requires. Polarises typically use TCW3 oils, which are clearly labeled on the bottles.
  
  

Original Equipment Manufacturer Oils

• These oils provided by the manufacturer are typically the best bets for your snowmobile,as they are manufactured, tested and approved for brand use. The National Marine Manufacturers Association ratings of TCW3 oils are most commonly used, while the American Petroleum Institute designation of API-TC is most often used for performance vehicles, according to Robert Verret in "The Late Great Oil Debate." Using a nonmanufacturer oil, however, will not void the warranty as long as you continue to use a two-stroke oil.
  
  

Petroleum-Based Oils

• Base oils are typically either petroleum- or synthetic-based. Curt Scott in "The Complete Guide to Specialty Cars" reports that "petroleum oil molecules, as contrasted to uniform-sized synthetic oil molecules, vary significantly in size, shape and length. When your engine heats up, the smaller molecules evaporate, while the larger ones tend to oxidize and become engine deposits." This means that petroleum-based oil is more likely to decompose at higher temperatures.
  
  

Synthetic Oils

• Synthetic oils are another option for your Polaris. There are a number of advantages to using synthetic oil as compared with petroleum besides the higher viscosity. According to Robert Verret in "The Late Great Oil Debate," synthetic oils stay cleaner because of fewer varnish deposits in the power valves, piston crown and ring lands. They also tend to decompose less quickly and transfer heat better.
  
  

Additives

• Additives are chemicals mixed with base oil to fix certain problems with the base oil. The additives fall into several general categories for two-stroke engines: detergent/dispersants, biodegradability, anti-wear and antioxidants. Detergents must be added to sweep residue out of the engine, biodegradability elements prevent harmful effects to the environment, anti-wear agents provide a barrier of lubrication between the moving parts in your engine after the oil film breaks down, and antioxidants extend the "shelf life" of the motor oil.
  
  

Various Brands

• Snowtech Magazine recommends 2-Cycle Extreme by Fowler Distributing, which in September 2010 was selling for about $18.95 per gallon (3.8-liter) bottle, for Polaris engines. Other brands available include Torco Synthetic/Petroleum 2-cycle Oil, at about $6.95 per liter, and Arctic Cat Semi-Synthetic at about $7.49 per liter. Just as in a car, if you find you don't like a particular brand of oil, check with your dealer to see if there may be a chemical reaction present between your old and new oils. If not, drain as much of the old oil as you can before adding the new. Check the types of additive packages that are present in each type of oil and decide which is right for your sled and your budget.