The supermarket initially said that it would carry out tests, but said it did not believe the diesel is of a poor standard.
But following further inquiries from the Worcester News, the company admitted finding water in one of the storage tanks at the superstore in Mill Wood Drive.
Customer Richard Davey said that Tesco had contacted his insurer admitting liability for the damage to his Ford Focus.
He said: “I filled it up at the Warndon store on November 20, and I know of at least five other people who had the same problem. I’m sure there will be a lot more out there, and some of them perhaps don’t know yet why their cars went wrong.”
Mr Davey, who works for Wychavon District Council, said: “They have agreed to pay nearly, £2,200, which covers the cost of the repair work, and I also hope to get the cost of the fuel back, and the cost of recovering my car, which was £90.”
The problem was originally reported to the Worcester News by driver Laura Yeomans, who said: “I filled my car up on November 28 with diesel and got the fuel filter warning light.
“I took my car into Kia who looked and found my tank was 50 per cent water.
“It has taken my car off the road and got me a massive bill to pay. I know of a few others who have had the same thing happen to them.”
A Tesco spokesperson said: “Our investigation has found an isolated case of water in one of the diesel storage tanks at our Worcester Warndon Superstore and we are in contact with and supporting the small number of affected customers. We apologise for any inconvenience caused.”
A similar problem was reported at a branch of Tesco in Bristol earlier this year.