NASCAR driver and car owner Tony Stewart says he's not going to keep quiet when he has safety concerns.

The three-time Sprint Cup Series champion was fined $35,000 on Thursday by NASCAR after suggesting that the series needs to do a better job of monitoring whether teams use five lug nuts during tire changes instead of letting teams take short cuts, using three or four, at the risk of safety.

Stewart, making his first start this season after missing eight races following back surgery, hasn't made himself available to media this weekend at Richmond International Raceway. But he did an interview with FOX as part of the pre-race coverage of Sunday's race on the 0.75-mile oval.