Cheaper oils are in the long run a false economy, In the first mile the higher volatility, inferior anti-wear performance and poor temperature resistance of a cheap grade of oil will start to show. Obviously, there will be no immediate effects. The whole point of top quality oil is long-term performance retention, which is particularly valuable to people who actually own the car they drive. The ‘performance’ enthusiast will want to retain the new-spec BHP figures, and the cost-conscious will want to see good fuel economy with 100,000 on the clock.
Cheap oil, (particularly 10W/40 or thinner) evaporates quickly, and the vapour is drawn into the combustion chambers via the crankcase ventilation system. This means calcium and zinc oxide deposits (from oil additives) which will cause pre-ignition, so the knock sensor retards the ignition, giving less power and poor fuel economy. The deposits also contaminate the exhaust catalyst, leading to high emissions and MOT failure. How much does an average catalyst box cost these days?!
In most cases synthetic oils (proper ones that is) are the way to go if you intend to keep the car or the car is somewhat special or used hard.
Cheers
Simon
Cheap oil, (particularly 10W/40 or thinner) evaporates quickly, and the vapour is drawn into the combustion chambers via the crankcase ventilation system. This means calcium and zinc oxide deposits (from oil additives) which will cause pre-ignition, so the knock sensor retards the ignition, giving less power and poor fuel economy. The deposits also contaminate the exhaust catalyst, leading to high emissions and MOT failure. How much does an average catalyst box cost these days?!
In most cases synthetic oils (proper ones that is) are the way to go if you intend to keep the car or the car is somewhat special or used hard.
Cheers
Simon