Nascar today penalised two championship contenders - including suspensions for Nationwide Series driver Austin Dillon's team - for problems found during qualifying at Daytona.

Three-time champion Tony Stewart was docked six points, and crew chief Steve Addington was fined $US25,000 because of a cooling hose found inside Stewart's car after his qualifying lap. Stewart forfeited his second-place qualifying spot, but still rallied to win Saturday night's Sprint Cup Series race.

Addington and car chief Jeff Meendering were both placed on probation through August 22, and listed car owner Margaret Haas was docked six championship owner points.

Stewart-Haas Racing said it would not appeal the penalties.

In the Nationwide Series, Dillon's team was penalized for the second consecutive week. Like Stewart, his car was found to have a cooling hose inside of it during his qualifying run and his time was also tossed out by Nascar.

But because it's the third time this season the No 3 owned by Richard Childress Racing has had an issue, Nascar cracked down on the title contenders.

Crew chief Danny Stockman was fined $US10,000, and he and car chief Robert Strmiska were both suspended through July 25, a span of two races. Nascar said the suspensions were because Stockman and Strmiska had already been on probation since May 1.

Dillon was also docked six points for the second consecutive week, as was listed car owner Morgan Shepherd.

It's a considerable hit for Dillon, who could be leading the point standings by four points but is instead trailing Elliott Sadler by eight.

Nascar also punished Joe Gibbs Racing for failing the post-race inspection after Friday night's Nationwide Series event when the car driven by Joey Logano was found to be too low.

Crew chief Adam Stevens was fined $US10,000 and placed on probation along with car chief Christopher Landis through August 22. Car owner Joe Gibbs was docked six championship owner points.

- AP