Polaris Industries recalled another 51,000 off-road four-wheelers Thursday after 13 customers reported that heat shields fell off their recreational vehicles, causing five fires. No injuries were reported.

This latest recall involves about 51,000 of the Medina manufacturer’s 2015 Polaris Ranger vehicles. Models affected include the Ranger XP 900, XP 900 EPS and Crew 900. Owners are being told to stop riding the vehicles and to take them to dealers for a free repair, according to a notice filed with the U.S. Consumer Product Safety Commission.

Thursday’s notice is roughly the 11th round of recalls Polaris has executed in two years. The company has told analysts that it expects to have recalled about 325,000 to 350,000 vehicles when all is said and done. Last year, Polaris paid out $132 million in total warranty costs and bolstered its warranty reserves by another $194 million in 2016 as it tried to address claims and fix machines with potential fire hazards.

It is unclear how much the new recalls will cost or if more are coming.

Analysts said they expect Polaris to give investors updated warranty cost estimates for 2017 when the company reports first-quarter earnings results on April 25.

Customers have been warned to stop riding recalled vehicles immediately and to take them into dealerships for free repairs.

After initial complaints about delayed parts shipments and repairs, Polaris doubled outreach efforts in the third quarter of last year. It reached out to customers directly, offering promotions and incentives designed to thank customers for their patience and loyalty.

Time will tell if it’s enough. Polaris’ recall problems hit at the same time the entire recreational vehicle industry is experiencing a slump in sales. Revenue fell 4 percent to $4.5 billion last year.

Polaris’ stock price fell 2.2 percent to close Thursday at $78.82. The stock is down from its 52-week high of $104 per share and down 49 percent from the $155 pricing levels enjoyed in 2015.