(CBS) – A warning to car owners: Some motor oils sold in Chicago are coming under fire by a petroleum group that says the oil could be bad for your car.

CBS 2’s Chris Martinez explains what drivers need to look out for.

In the simplest of terms, it can be poison for your car and do damage to your engine.

Tom Glenn of the Petroleum Quality Institute of America is talking about motor oil, some of the cheapest around. He says the product is mislabeled and dangerously outdated.

He says some of the product “was appropriate for cars built prior to 1930.”

Seven states have already banned a number of these products, finding them for sale the most in urban areas.

CBS 2 found some of the product at convenience stores on the city’s North and Northwest sides.

Some labels say the oil is for “older cars” but doesn’t explain what that means. One container actually says it’s recommended for cars built before 1988.

“Consumers have no idea,” says garage owner Matt Tefka.

He says reading the labels is critical, pointing out legitimate bottles of oil lude a couple of key codes, including ISACGF5. Use the bad stuff, he warns, and the damage could be severe.

“It may not be in the first thousand, two thousand miles, but down the road, if something happens, good chance it’s because you’ve been using the improper oil,” Tefka says.

The bottom line from mechanics: Steer clear of generic brands and read the labels carefully.

As for who’s looking out for consumers here, the Illinois Department of Agriculture says inspectors are on the lookout for this oil, calling it an emerging issue. CBS 2 has reached out to a couple of the manufacturers but has not heard back.

A spokeswoman for the Chicago Department of Business Affairs and Consumer Protection said officials are looking into the complaints about the products.

“The City works to ensure that all businesses are selling safe merchandise. We will look into these products to determine if they are harmful to consumers and will reach out to all relevant businesses to inform them of the potential safety concerns as well as work to educate consumers on this situation,” a written statement said.