Short trip driving is tough on engines

According to a recent survey conducted by the U.S. Bureau of Public Roads, 63 percent of motor vehicle trips equal six or fewer miles.  The American Petroleum Institute, however, has indicated that engines require as much as six miles of travel to reach normal operating temperatures.  Frequent short trips often allow water, fuel and acids to accumulate in the oil and sludge and varnish to form in the engine.  AMSOIL synthetic motor oils are formulated to protect engines from the rigors of short-trip, severe-service driving.

Water:  Water is a normal combustion by-product that bypasses the piston rings in its gaseous state, then condenses on internal engine walls when the motor oil is not warm enough to drive it off as steam.  Circulating oil picks up the water and carries it to the oil filter. Full flow filters cannot trap water, so it continues to circulate with the oil, where it depletes additives and reduces the oil's ability to lubricate.  If the oil is heated to "normal" operating temperatures (200-220 degrees F), the water returns to a gaseous state (steam) and is vented out of the engine.  However, when the engine is shut down, the water may accumulate on engine metals, promoting rust.  AMSOIL synthetic motor oils contain top-performing anti-rust agents that cling to metal surfaces and protect them from rust even when the engine is not running.

Fuel:  In vehicles equipped with carburetors, fuel accumulates in the oil during repeated short-trip driving because the engine runs with a closed choke when it's cold.  The closed choke allows more fuel than can be burned into the combustion chamber.  The excess fuel bypasses the rings and gets into the crankcase.  Warming the engine to normal operating temperatures, as usually occurs during trips longer than six miles, promotes fuel evaporation.

With the advent of fuel injection systems, fuel dilution problems have been significantly reduced.  Using AMSOIL Performance Improver can keep fuel injectors free of deposits and working properly.

Acids:  Some fuel by-products interact with water to form acids.  The water must be in its liquid form, so this process takes place more readily in the cool short-trip engine than in the warm long-trip engine.  AMSOIL synthetic motor oils are high TBN (Total Base Number) oils, which means they have maximum acid-neutralizing chemistry.  Most passenger car motor oils are formulated with significantly less TBN than AMSOIL synthetic motor oils do.

Sludge and varnish:  Sludge (a soft, sticky material that accumulates on surfaces) and varnish (a hard material that adheres to surfaces) form as water, acids and other oil contaminants interact in the oxidizing engine environment. Since short-trip driving encourages water contamination of the engine oil, vehicles frequently engaged in short-trip driving are prone to developing sludge and varnish.  Because AMSOIL synthetic motor oils are highly resistant to oxidation and contain powerful acid fighting TBN chemistries and high-quality detergents and dispersants, their use inhibits sludge and varnish formation.

Extended drain service:  The high TBN, generous anti-rust content, high-quality detergents and dispersants and outstanding oxidation resistance of AMSOIL synthetic motor oils allows them to be used for extended drain intervals, even in short-trip driving, and still provide better engine protection than conventional oils do.  But always remember to observe time and mileage when calculating drain intervals with XL-7500 products.  It's time for a change when you accumulate 7,500 miles or have been driving with the oil installed for 6 months, whichever comes first.