Team 5 Investigates has found cracked valve stems on three separate 2007 model year vehicles, each of which was manufactured by Ford.

“It was cracked all the way around," said David Kidd, who checked his 2007 Ford F-150 after seeing our Team 5 investigation into cracked valve stems.

What To Look For | Photos: Spotting Defective Valves

“One of them, I moved it, and I thought it was going to fall off,” said Kidd. “I was concerned about a blow out, having a rollover, or worse.”

Valve stems allow you to put air into a tire. Even a small crack can allow air to leak out, causing a flat or a crash.

Watch report

Two local Ford dealers confirmed that all four of Kidd's F-150’s valve stems were cracked and rotten.

A cracked valve stem is suspected of causing an accident in Florida last November in which a 31-year-old man was killed. His family has filed a lawsuit.

“I wouldn't have looked at those valve seals if you hadn't run that story,” he said.

Kidd isn't alone. Team 5 Investigates first reported Monday that there could be more than 30 million potentially defective valve stems on replacement tires as well as on cars and trucks bought new.

Additionally, NewsCenter 5 found three cracked valve stems on one of our 2007 Ford Explorers, and one cracked valve stem on another station vehicle.

The National Highway Transportation Safety Administration is investigating valve stems made in 2006 at a Chinese plant. Already, one distributor of those valve stems has issued a recall. Another distributor is under investigation.

In a statement to Team 5 Investigates, Ford acknowledged using valve stems from the factory in question but denied that “any valve stems used on Ford vehicles are part of any investigation.” So far, Ford has not explained the cracked valve stems found on our two SUVs and Kidd's F-150.

WCVB-TV has filed a formal complaint with NHTSA about the cracks found on our valve stems.