Genuine 1990 Mazda 323 Thermostat

1990 Mazda 323 Thermostat Parts and Q&A

• Q: What steps should be taken before assuming the thermostat is responsible for a cooling system problem on 1990 Mazda 323?

  A: Before blaming the thermostat, check coolant level, belt tension and gauge. Slow warm-up indicates stuck open; hot engine with cool lower hose indicates stuck closed. Driving without one worsens emissions and economy. To replace: disconnect negative, drain coolant, remove hose/cover, swap thermostat noting orientation, reassemble, refill and check leaks.