Through a glass door and stacked in a back room sit shelves of child safety seats wrapped in plastic. For just a few dollars a day, parents can rent these car seats at Advantage Rent-A-Car.

But our Problem Solvers undercover investigation found what you pay for may actually be dangerous.

When Seattle mom Debbie Dubrow rented a car at an Advantage lot in San Diego last December, she found a critical restraint clip missing from the seat.

Her husband was led to the storage room in back to pick out a replacement.

"It was just a scrap heap of these just filthy car seats," Debbie said. "A lot of them were clearly broken."

The couple snapped photos to document the mess. They showed car seats covered with stains, dirty straps and missing parts.

After looking through the stacks of seats, Debbie settled on a Fisher Price T-Shield model that appeared to be in working order.

Turns out it is 18 years old -- made in 1990. Federal guidelines say safety seats should be replaced every 10 years, and most manufacturers recommend replacement after 5 years.

"And so at that point I knew that what they had there was really just completely unsafe," Debbie said.

She reported the bad and broken seats to the manager, including the 1990 Fisher Price T-Shield.

But a month later, when our sister station rented four car seats from that same San Diego location, we found that 1990 Fisher Price safety seat still available.

And we found similar concerns at an Advantage rental location near Sea-Tac Airport. We rented three seats and asked a technician at the Washington State Safety Restraint Coalition to analyze them.

It didn't take Jennifer Pavey long to find problems.

"This harness, which will hold the child in, is beginning to get moldy," she said while holding one of the seats. "There's also a small rip here. In a crash those kinds of things can change performance. This particular seat I would not want to see used anymore."

We went back to Advantage with the moldy car seat. At first, the manager refused to answer our questions, then he claimed the seat didn't belong to Advantage.

"You know what, this is crap," Manager Kevin Lake said. "It doesn't even have one of our Advantage stickers on it. We wouldn't rent this."

But Advantage did rent us that moldy, torn seat, and we have video of it being loaded into our rental car.

Confronted with the findings, Advantage officials sent us a letter saying, "we are very concerned with the issues raised by your investigative team."

The company ordered an immediate inspection of all child safety seats and says the questionable seats have been removed from the rental pool.

Advantage has also made sweeping changes in it's child safety seat policy. From now on, Advantage car seats will be replaced every two years - better than the replacement schedule recommended by manufacturers and the Federal government.

And the company says each rental seat will be accompanied by the owner's manual so customers will know how to use the seat.

For Dubrow's family, however, the change comes too late. From now on she'll travel with her own car seats.

"I wouldn't want to put my kids at risk like that," she said.

For More Information:

Read the response letter from Advantage

Read more about Debbie Dubrow's experience

Car seat safety information