Synthetic Oils
Just had a question for you folks. When is it ok to change out the old dino oil and replace it with synthetic? I just changed our oil at about 10,000 miles, second change, and wonder if I should loo...
Forum Discussion
So long as the base stock oil meets the API standards it matters not at all whether you use mineral or synthetic motor oil. The only exception is in extremely cold (below 0 degrees F) or extremely hot (plus 120 degrees F) weather. The synthetic formulations that are 5W40 will provide less protection under most driving conditions than a 15W40 mineral oil. 15-20% of what is in a gallon of oil are additives and it is these additives that determine how well the oil performs.
Synthetics which cost 2-3 times as much as mineral oils cannot be justified because the oil can be changed less often. The additive package consisting of detergent, dispersant, and antioxidants will degrade over time regardless of the type of base stock that is used. The only way to replenish this additive package is to take out the old oil and put in new oil.
With diesel engines there is also an accumulation of soot and sludge and the only way to remove this from the oil is by changing out the oil and the filter. The more severe the duty level the more frequent the need to change the oil and it can change by a factor of 4.
I grew up in the days of STP and the "racers' edge" advertising and people still buy into this today with synthetic motor oil. The only places where synthetics are better is in the transmission.
Synthetics also are subject to a phenomena known as polymer shear that occurs with multi-grade motor oil as it passes through the small openings in a bear journal and its effective "weight" is greatly reduced. A 5W40 motor oil may become a 1W40 motor oil and this will greatly accelerate bearing wear.
The exception to all this is cheap mineral oils which are rated as Grade I or Grade II and do not meet the API standards for a Group III motor oil. The bargain oils are not a good choice unless your engine is already burning through oil at a rapid rate.
I consider heavy hauling and towing to be "severe" duty and adjust the service intervals based on the percentage of time the truck is used in this manner. For me it is 50% so I average the severe and normal duty recommendations on motor oil and ATF and filters replacement for the engine and transmission.
I have put more than 170,000 miles on each of the 8 trucks I have owned and my brother has over 300,000 miles on his Toyota and we both use only mineral oil in our trucks and we have never had an engine failure or even enough ring and cylinder wear to require adding oil between changes.
Synthetics which cost 2-3 times as much as mineral oils cannot be justified because the oil can be changed less often. The additive package consisting of detergent, dispersant, and antioxidants will degrade over time regardless of the type of base stock that is used. The only way to replenish this additive package is to take out the old oil and put in new oil.
With diesel engines there is also an accumulation of soot and sludge and the only way to remove this from the oil is by changing out the oil and the filter. The more severe the duty level the more frequent the need to change the oil and it can change by a factor of 4.
I grew up in the days of STP and the "racers' edge" advertising and people still buy into this today with synthetic motor oil. The only places where synthetics are better is in the transmission.
Synthetics also are subject to a phenomena known as polymer shear that occurs with multi-grade motor oil as it passes through the small openings in a bear journal and its effective "weight" is greatly reduced. A 5W40 motor oil may become a 1W40 motor oil and this will greatly accelerate bearing wear.
The exception to all this is cheap mineral oils which are rated as Grade I or Grade II and do not meet the API standards for a Group III motor oil. The bargain oils are not a good choice unless your engine is already burning through oil at a rapid rate.
I consider heavy hauling and towing to be "severe" duty and adjust the service intervals based on the percentage of time the truck is used in this manner. For me it is 50% so I average the severe and normal duty recommendations on motor oil and ATF and filters replacement for the engine and transmission.
I have put more than 170,000 miles on each of the 8 trucks I have owned and my brother has over 300,000 miles on his Toyota and we both use only mineral oil in our trucks and we have never had an engine failure or even enough ring and cylinder wear to require adding oil between changes.
