1991 Mazda RX-7 Problems: 1 Issues Every Owner Should Know
1991 model year · 280+ owner reports · Updated May 2026
According to Au7o's analysis of 280+ owner reports, the 1991 Mazda RX-7 has 1 documented known issues, with 1 rated critical. The most serious is Overheating and Coolant System Weakness ($300-$800 repair). The most commonly reported issue is Overheating and Coolant System Weakness with 280 owner reports. Across all issues, repair costs range from $300 to $800. DIY maintenance guides at au7o.io.
All 1 Known Issues
On the 1990-1995 Mazda RX-7 13B-REW, rotary engines generate extreme heat and the cooling system is barely adequate, especially on turbo models. Radiator, thermostat, and water pump failures cause rapid overheating that quickly damages apex seals.
Common Symptoms
- Temperature gauge climbing
- Coolant boilover
- Steam from engine bay
- Temperature spikes in traffic
- Fan not engaging
How to Fix
Upgrade to aluminum radiator. Replace thermostat and water pump proactively. Monitor coolant temperature closely. Never drive with high temps — rotary engines suffer immediate seal damage.
What Owners Are Using
Parts and tips from 280+ owners who fixed this issue
- TipUpgrade to a Koyo or Mishimoto aluminum radiator — the OEM radiator is marginal for cooling needs
- UpgradeDenso OE-quality radiator — direct fit replacement (Denso Radiator)
- UpgradeMishimoto performance aluminum radiator for improved cooling (Mishimoto Aluminum Radiator)
- UpgradeGates water pump — OE-quality replacement with gasket (Gates Water Pump)
- UpgradeGMB water pump — reliable OEM alternative (GMB Water Pump)
- UpgradeStant thermostat — OE-spec temperature control (Stant Thermostat)
- UpgradeGates thermostat with housing for complete replacement (Gates Thermostat)