The contact owns a 2017 Toyota Prius. The contact stated that while driving approximately 25-30 MPH, the vents were blowing out cold air. The check engine warning light was illuminated. The contact was adding coolant to the coolant reservoir every three to four days. The vehicle was taken to the local dealer, where it was diagnosed and determined that the coolant was leaking into the exhaust pipe. The dealer recommended that the exhaust system front pipe be replaced. The manufacturer was contacted, opened a case, and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 81,700.