A study by a new vehicle-appraisal technology provider indicates a significant percentage of people who sell used cars knowingly do so without revealing serious mechanical issues that haven't been repaired.

The results of a September survey AppraisalPro commissioned of 500 Americans who bought or sold a car at a dealership in the past five years show one in five sell used vehicles with such defects, and 16% said they didn't disclose them to the buyer.

Sixty percent of survey respondents sold at least one vehicle during the five-year period, three out of four making their most recent sale to a dealer, the company said.

“Used auto buyers are concerned enough about transparency that they’re willing to pay for it,” AppraisalPro Dealership Manager Leslye Guthrie, who said dealers can tap diagnostic tools to ensure used cars they sell are free from serious mechanical issues.

The research showed vehicle buyers tend to trust dealerships over private sellers 68% to 5%, though more than a third of survey respondents said they’ve passed over a dealership car purchase due to feelings of mistrust, AppraisalPro said.