SilverMax_04

I was in Chicago on May 16 and saw an article in the Car Section of the Tribune on the new grade of motor oil. I found it informative, and will copy it here.

Bob Weber is an ASE-certifice Master Automobile Technician, having recertified every 5 years since 1978.

It seems that not a year goes by that we hear that some oil is better than another. No, we're not talking about olive oil's cholesterol-lowering benefits. We're talking about the latest motor oil: GF4.

GF4 is important if you bought a 2005 or newer car or light truck with a gasoline engine. Check your owner's manual, it may specify GF4, which was created because of longer oil-change intervals. Intervals have been stretched for many reasons: Many car owners don't change the oil when they should; engines are running hotter; and the EPA demands better fuel economy, lower emissions and properly functioning emissions systems.

Initially, there was a lot of concern about the new oil because it contains much less phosphorus -- 20% less. Phosphorus is one of the best anti-wear additives in motor oil. At the molecular level, phosphorus acts like a cushion to help prevent engine parts from touching one another. But there is evidence that phosphorus tends to coat the catalysts in the converter, reducing its effectiveness.

That created concern over how well older engines would be protected. Also, fast-lube shops, independent service facilities and retail stores were concerned that they would have to stock the new and old oil. Then there was the issue of do-it-yourselfers' cofusion over which oil to buy because new generations of motor oil traditionally were compatible with the previous generations.

GF4 was introduced in August 2004. Though it is meant for 2005 and newer vehicles, it's also acceptable for pre-2005 models. That's because the anti-wear testing of the new oil was more stringent than before to ensure the phosphorus reduction would not lead to damage.

The testing was conducted by the International Lubricant Standardization and Approval Committee (ILSAC), which bestowed the GF4 designation. ILSAC is a coalition of American and Japanese automakers, oil additive companies and oil companies. ILSAC, much like the American Petroluem Institute (API), tests automotive oils by running bench and dynamometer tests to make sure engine components are adequately protected.

Early bottles of GF4 bear the API SL designation because the institute did not give its approval until the end of November. That's when it got the API SM grade. Look for SM at the top of the API doughnut symbol and for the starburst symbol on the bottle that certifies it meets ILSAC GF4 standards.

If you have used the wrong oil in your new car, chances are there will be no ill effects -- if you change your oil on time. Using the old GF3, API SL oil two or three times should only slightly reduce fuel economy until you switch.

If, however, you put excessive demands on your oil by heavy engine use such as towing or if you extend your drain intervals too long, the older oil may oxidize and thicken, becoming sludge. Thick oil has trouble flowing at low temperatures and leads to engine wear. Extended use of the wrong grade also can lead to piston deposits and increased oil comsumption.

And remember what those phosphorus deposits may do to catalysts. While this probably won't cause you car to fail the emissions test, it could shorten the catalytic converter's life that, by law, is warranted to last 120,000 miles. Owner abuse can void the warranty.

Bottom line? If you own a model year 2005 or newer vehicle, use the new oil. If you own an older car or truck, you may be able to find some deals on the older oil as stores and shops clear out their inventory. It may be a good time to stock up.

knapp9

iTrader: (1)

This author is right on, but a little late. All the good closeout buys on oil were back in January as the API SM oils first hit the shelves and retailers cleared out their older SL oils. The shelves in Walmart, AutoZone and Sears around here were pretty much picked over by the end of February.