This speaks to cars newer than 1999 and have less than 200k miles and do not use or leak alot of oil.
The best way we meausure the quality and effectivmness of motor oil is by looking at the temperature range it will protrect your engine. During VERY cold weather your oil will turn to a wax and obvioulsy not lube your moving parts. During high heat conditions, your oil will burn, turn to a tar or a solid and cause your engine to fail. Depending on the brand of oil and your car maker, the following are parameters that apply to almost all 2000 and newer cars and light trucks.
Conventional motor oil is mostly from Mother Nature. Conventional motor oil turns to wax at -25f or so and turns to a tar at 300f or so. So Conventional oil needs to be changed in the 2,500 to 4,000 mile range. If you drive 15k a year, you will need 5 oil changes and spend about $125 to $175 (mrkt is $25-$50 an oil change)
Semi-synthetic oil is some percentage of man made oil base stock and the rest is conventional oil. You can get 5/95% split all the way to 50/50 mix. Semi-synthetic motor oil turns to a wax at -35-40f or so and turns to a tar at 425f or so. So semi-synthetic motor oil needs to be change in the 4,500 to 7,000 mile range. If you drive 15k a year, you will need 3 oil changes and spend about $75 to $150 (mrkt is $40-60 an oil change)
Full synthetic oil is lamost all made by man. No foaming, will burn up long after your motor is dead and cleans your engine better. Full synthetic motor oil turns to a wax at -60f or so and turns to a tar at 500f or higher! So full synthetic motor oil needs to be change in the 7500 to 700 to 10,000 mile range. If you drive 15k a year, you will need 2 oil changes and spend about $150 ($75 an oil change)
So if your car is not using or leaking oil and I can reduce your annual oil changes from 5 to 2 and you still pay about $150 a year, what’s holding you back?
My wife is driving a 05 Tahoe, she is using a semisy 5/30 and using a 7,500 oil change interval. I use a 5/40 semi syn in my 06 GMC 3500 one ton and change it every 7,500 miles as well. In motorhomes we use a convential oil 10/30 in the generators and use a 100 hour change interval. We use a 5/40 semi sy OR full syn on the coach engine and use a 10k oil change interval. But most take as much as 26 qts!
The default is what it always has been, check your owners manual for direction.
Bio: Hi, I’m Mark. My wife, Ranae, and I have owned and operated Salem Boys Auto since 1979. I am also very proud to be an ASE Certified Master Tech, along with 9 other guys in our shop. Of the 9 Masters, four (including me) have their L-1 rating which is an advanced engine performance certification. Salem Boys Auto is an ASE Blue Seal shop and an ASA Gold Medallion shop. Salem Boys Auto is not just any kind of repair shop but, a repair shop that has won numerous awards for its design, its environmental strategy, its beauty and functionality.
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My background includes 2 years with GM, Ford and Chrysler as an arbitrator and/or technical advisor. I was on the board for the BBB, I am a court appointed special advocate (CASA) for many young men and I host a few weekly radio shows about car repair and appear regularly on TV about car repair related issues. Folks trust me to guide them through their car repairs and I don't take that responsibility lightly. I've been giving car repair advice on local radio and TV since November of 1987. I was the original "NASCAR Consumer Crew Chief" for three years.
At our shop, on radio or TV, your interests are well in front of my interests, my shops interests or our Technicians’ interests. YOU are #1 and what is best for you is miles in front of, what is best for me. I know right from wrong.
I have been married since 1974 to my high school sweetheart. I am a Husband, a Father, a Grandfather, an automotive expert, an arbitrator and mediator, a cowboy and the luckiest guy in the world.