Those commercials tickle me–seriously though after an unusual day of oil changes it got me to thinking how little people know about oil. Oil is the life blood of your car, and its one of the most important things you can invest in. The most common question I get (as my profession dictates I receive many car care questions) is; “What kind of oil should I use?” Honestly the answer isn’t as hard as many people like to think. Allow me to explain..
Brand is just that… a brand. Truthfully no one oil is better than another, but where brand does matter is in the quality of the process used to manufacture the oil. Higher priced brands such as Valvoline and Havoline take more care in the manufacturing process than say an cheaper brand like Wal-Mart’s infamous Super-Tech.
Synthetic & Crude have a few difference, perhaps the most obvious it that synthetic is manufactured without any crude oil input, whereas crude is derived from crude barrel oil in a refining process.
Weight (Viscosity.. or Thickness) is very important … using too heavy of an oil can lead to major engine problems and possibly permanently disable an engine. Now the numbers in the grade denote what its weight is cold and what it is at operating temperature, for reference 5w-20 is almost as as thick warm as 10w-30 is cold… the numbers being viscosity/temperature multipliers. You can see an excellent article explaining weight at AMSOil Tech.
I have a few guidelines when changing oil that I follow that might be help in the selecting of the proper grade of oil …
For Newer Import & Domestic compact cars with a small liter four cylinder I most commonly use 5w-20 synthetic oil. For Newer Imports & Domestic (Older Imports) with smaller V6 engines I’ll typically use 5w-30 synthetic.
10w-30 is a great base oil for most all vehicles that have V6 and smaller V8 engines. Newer engines I’ll use a synthetic blend, but older ones (98′ and earlier in my book) I’ll tend to use crude base oil. (Remembering that crude base oil is slightly thicker than synthetic)
Heavier weight oils should be used as prescribed by the vehicles service or owners manual although some older vehicles (those with warn valve guides …. etc.) sometimes benefit from running a heavier 10w-40 oil. Many muscle car era vehicles ran 10w-40 until the advent of a thicker synthetic; Royal Purple, which is manufactured synthetically but has crude oil characteristics.
Filters as another very important item and there are many good options, FRAM is becoming the industry standard across the board along with Wix. Both of these are good options (and inexpensive) however most people benefit from using the brand directed by the service manual, such as a GM vehicle would use a AC-Delco filter. The reason for a benefit is because, FRAM filters are manufactured differently (mass manufactured to cover a wider range of applications sacrifices fine tuning of the filter) than AC-Delco, and you have to remember when that GM engine was designed it was using an AC-Delco oil filter. Consequently the AC-Delco has slightly better fluid flow than the FRAM, which leads to better fuel mileage and a cooler .. smoother running engine.
I can tell you from experience that I’ve used FRAM filters for a number of years on my work vehicle (89′ S-10 Blazer, 4.3l V6, Auto) and recently (well about a year ago) switched to AC-Delco and I’ve had great success. My oil has been cleaner, and my engine is running about 10 degrees cooler than it was.
Hopefully this has enlightened you a little more about oil and helps you make wise choices on one of the biggest investments on your vehicle. Remember though even though I am an ASE certified, I don’t have the privilege to over-ride your owners manual, so always consult it concerning any oil questions and then… and only then.. if your not satisfied talk to your car care professional.
