I bought a 2007 Mercury Grand Marquis "program car" in Sept 2007 from a Ford dealer. When I bought it it had 10,000 miles on the odometer and the original tires which were in great shape. Within the first 2 months of ownership two dill valve stems failed, in each case creating a dangerous driving situation and in each case costing me approximately $200 to replace the associated tire. After the second failure I had the remaining 2 valve stems replaced and they too showed signs of cracking. I feel dill owes me $400.

- Inyokern, CA, USA

I had a tire valve fail. The repair shop pulled the tire apart and the tire was perfect. They said that the valve probably was defective. 2007 Mercury Grand Marquis w Michelin tires ( mileage about 14,000 miles).

- Ocala, FL, USA

During the month of Aug 08 I had 3 flat tires. In each case the tire went flat while traveling on a roadway at speed. Each flat was caused by a valve stem failure (cracked and leaked)the first failure seemed like a normal event, the second seemed questionable, the third was absolute confirmation of a clear problem with the valve stems. The valve stems were replaced on the 3 tires as well as the 4th before another valve stem failure. The 3 tires that went flat sustained sidewall damage. The valve stems on this vehicle were clearly defective and potentially very dangerous to the operation of this vehicle (or any vehicle with these type of valve stems) by an inexperienced operator.

- Holden, MA, USA