The 1993 Mazda RX-7 has 5 recalls, the most serious being two overlapping fire risks: a radiator cap that lets coolant overheat and spill onto the exhaust manifold, and fuel hoses that deteriorate from engine heat and can leak.
Both fire-related issues stem from the engine's heat characteristics. The radiator cap's pressure relief valve is set too high, allowing coolant to exceed the temperature limits the cooling system was designed for. When coolant leaks from the top of the engine and contacts the hot exhaust manifold, it can ignite an engine compartment fire. Separately, residual heat after the engine is switched off causes the rubber fuel hoses to lose their elasticity and seat poorly at their connections. This can allow fuel to seep out near hot engine components, again creating a fire risk. Prior repair attempts on the fuel hoses carry an added concern: removing and reinstalling hoses that are already deteriorated increases the chance of a leak rather than eliminating it.
On the brake side, oil mist from the engine's intake air can accumulate inside the brake vacuum check valve over time and prevent it from opening at the pressure it was designed to. The practical result is reduced braking power on the first one to three brake pedal applications after the vehicle has sat overnight and is restarted cold, which means the brakes may feel less responsive when the driver first pulls out in the morning.
