Dayton Daily News

Wheels: Jay of Washington Twp. writes, "Can you please advise me as to whether or not it is possible to test (in a lab) for Mobil 1 oil versus the typical fossil fuel-based oil? I've wondered if the Mobil 1 was actually used. These are my specific questions:

1. Is it feasible to take old oil and test it to identify which it is?

2. Where might one have such a test performed? (a local lab, or ... ?)

3. How much oil would be needed for the test? (a few drops, 1/4 cup ... ?)

4. Would you venture a rough cost 'guesstimate' for the process?

Thanks in advance for your consideration. You're doing a valuable service by affording the Wheels reader an opportunity to resolve some vexing/technical issues. Please keep up the super work, and kudos to the Dayton Daily News for publishing your column!"

Halderman: Thanks for the kind words. There are some local testing labs that can perform an oil analysis, but the most commonly used engine oil testing lab is Blackstone Labs (www.blackstone-labs.com) in Fort Wayne, Ind. It requires about 3 oz. to 4 oz. of oil for them to test the oil. Contact them for a free sample bottle to send in your oil sample and details about the tests to be performed. Normally, they cannot tell if the oil is synthetic or mineral; instead they test for wear metals and other materials that can indicate engine wear or coolant leaks. The cost is $22.50.

Wheels: Another related question comes from Jim of Dayton, who states, "Recently, I had the first free oil change at the dealer and they showed on the work order that they used SAE 10W-30 oil. I checked my owner's manual and it stated that the specified oil should be SAE 0W-20.

They said that that thin of oil is only needed to be used in very cold climates and that they always have used SAE 10W-30 without any problems.

Is that true?"

Halderman: The dealer should only use the oil specified for use in your vehicle as stated in the owner's manual. The owner's manual has been checked not only by the engineers who designed the vehicle, but also the legal department to make sure that the product adheres to all fuel economy and emissions regulations.

Wheels: How can the viscosity of the oil affect emissions?

Halderman: The engine designed to use SAE 0W-20 engine oil would likely be equipped with low-tension piston rings. If thicker oil were used, the tension of the rings against the cylinder wall may not be strong enough to remove the oil that is thrown up on the cylinder walls. Then, this oil is forced out of the combustion chamber and into the catalytic converter. Because this can interfere with the emission controls mandated by the U.S. Environmental Protection Agency (EPA), it could be considered "tampering" if the incorrect engine oil is used in an engine that is used on the public streets and highways.

James D. Halderman is an ASE-certified master technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. Submit your automotive care questions to Halderman via e-mail at jhalderman2@juno.com, or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 1611 S. Main St., Dayton OH 45409.