My daughter and Son-in-Law just purchased a nice used car with approximately 25,000 miles. The question- is there any benefit in using synthetic lubricants over Petroleum base lubricants in the crankcase? The vehicle is serviced every 3 to 4K miles with both oil and filter. When does it become beneficial to use one over the other from a cost factor when considering operating expenses and engine life?

Yes. It's much cheaper, over the long run, to use synthetic engine oil and synthetic automatic transmission fluid from the beginning. With the constant price promotions on synthetic engine oil, there's no economic reason to do otherwise, if you change your own oil and filter. Even if you pay "full boat," it's still worth it. One of the best tests of your preventive maintenance program is the emissions test. My 1993 Civic (bought new) has only used synthetic engine oil. Several months ago, when I took it in for the Texas emissions test, my car tested at 6 ppm of CO--it was allowed 200. The examiner told me the test results were like those of a new car. The advantages of synthetic lubricants are so apparent that it's hard to justify not using them:

. Superior wear protection.. . Engines last longer
. Improves fuel economy.. . More miles per gallon
. Easier cold starts
. Easier on batteries and starter motors
. Cooler running engines in high heat
. Reduces engine deposits
. Resists oxidation and thermal breakdown
. Increases horsepower
. Superior shear stability and film strength
. Extended drain intervals produce environmental benefits
. Reduces exhaust emissions

What we are talking about here are high-tech, "designer molecules," precisely engineered for the application. I can easily see the day when using synthetics could be mandated to preserve the environment. Do your part to keep the air we breath clean, conserve oil and gasoline, and reduce global warming by using synthetic lubricants.

IAgree With Greasemonkey. Cost More Per Qt,but Well Worth It. :)