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Re. “Motor oil and the environment,” Ask Eartha, Feb. 2
As an engineer by training (35 years of experience) and long-time car enthusiast, I want to take exception to parts of your recent article on motor oils. I have a strong understanding of lubrication science and want to clarify several points made in the article.
The owner's manual is clearly the right place to start to determine how often to change engine oil. Keep in mind, however, the manufacturer's goal is not to maximize the life of your engine, only to assure that the engine operates reliably through the warranty period. Oil change service companies want to sell engine oil changes and thus recommend more frequent oil changes. The correct answer is typically in between. The real issue is for the car owner to properly assess the true service duty of the car and care for the car appropriately. Most drivers do, indeed, operate their cars in the “severe” mode, and more frequent oil changes are appropriate.
Changing engine oil is the most cost-effective method to extend the life of the engine. The statement in the article that more frequent oil changes will not extend the life of the car (engine oil will only extend the life of the engine — the car is another story) is simply wrong. Obviously, there is a point of diminishing return, but oil can lose much of its critical properties in less than 5,000 miles of severe service. The oil filter should always be changed with the engine oil as well (even though some manufacturers recommend oil filter changes every other oil change).
The real environmental question is whether more frequent oil changes and the resulting improved engine life (and fuel economy) results in fewer cars being built and the reduced resources consumed overall. Government and independent research studies have shown that a properly maintained car can operate for 15-20 years. The resources consumed by keeping a well-maintained car is far lower than a vehicle that finds its way to the junkyard in 10 years or less.
Standard mineral-based oils are much better today in terms of reduced engine wear, corrosion and sludge control. The synthetic oils are superior in performance, particularly in corrosion and sludge control. Understand that very few “synthetic oils” are in fact made using non-mineral oil base stocks. A true synthetic oil is made from PAO or ester base chemicals that can maintain lubrication at very high temperatures (greater than 400 F).
I agree that used engine oil must be properly disposed to protect the environment. Very few people change their own oil, and only the most uninformed backyard mechanic would throw used oil down a drain or into a creek. Dealerships and oil change companies always recycle because used engine oil is valuable! That's why Walmart, Jiffy Lube and many other firms will gladly take your used engine oil. A note of clarification: Do not mix other liquids in the oil. Brake fluid, antifreeze, transmission oil, paint thinner, etc. should not be mixed with engine oil. It can not be properly reused if contaminated,
Most current re-refined engine oils available are very good oils and fully meet the manufacturer's SAE service requirements. Many of the new bio-based oils (soy, corn and castor) are also good oils, but always check to confirm that they meet the required SAE Service Duty level for the car.
This may be more than you ever want to know, but far more accurate for your readers to make sound decisions. Journalists and particularly environmental journalism have become far too sound bite and agenda driven. The issues we face today are complex, and only accurate, complete information will assure good policy and positive results are achieved. Half truths and incomplete information is not helpful. Do your homework — then write your story!!
Changing engine oil is the most cost-effective method to extend the life of the engine. The statement in the article that more frequent oil changes will not extend the life of the car (engine oil will only extend the life of the engine — the car is another story) is simply wrong. Obviously, there is a point of diminishing return, but oil can lose much of its critical properties in less than 5,000 miles of severe service. The oil filter should always be changed with the engine oil as well (even though some manufacturers recommend oil filter changes every other oil change).
The real environmental question is whether more frequent oil changes and the resulting improved engine life (and fuel economy) results in fewer cars being built and the reduced resources consumed overall. Government and independent research studies have shown that a properly maintained car can operate for 15-20 years. The resources consumed by keeping a well-maintained car is far lower than a vehicle that finds its way to the junkyard in 10 years or less.
Standard mineral-based oils are much better today in terms of reduced engine wear, corrosion and sludge control. The synthetic oils are superior in performance, particularly in corrosion and sludge control. Understand that very few “synthetic oils” are in fact made using non-mineral oil base stocks. A true synthetic oil is made from PAO or ester base chemicals that can maintain lubrication at very high temperatures (greater than 400 F).
I agree that used engine oil must be properly disposed to protect the environment. Very few people change their own oil, and only the most uninformed backyard mechanic would throw used oil down a drain or into a creek. Dealerships and oil change companies always recycle because used engine oil is valuable! That's why Walmart, Jiffy Lube and many other firms will gladly take your used engine oil. A note of clarification: Do not mix other liquids in the oil. Brake fluid, antifreeze, transmission oil, paint thinner, etc. should not be mixed with engine oil. It can not be properly reused if contaminated,
Most current re-refined engine oils available are very good oils and fully meet the manufacturer's SAE service requirements. Many of the new bio-based oils (soy, corn and castor) are also good oils, but always check to confirm that they meet the required SAE Service Duty level for the car.
This may be more than you ever want to know, but far more accurate for your readers to make sound decisions. Journalists and particularly environmental journalism have become far too sound bite and agenda driven. The issues we face today are complex, and only accurate, complete information will assure good policy and positive results are achieved. Half truths and incomplete information is not helpful. Do your homework — then write your story!!
