High Temp Thermostat

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• Objective:
  • Maximum fuel efficiency
• Fits:
  • all AHU/1Z TDI's
  • ALH
  • All older IDI's
• Part Numbers:
  • Wahler P/N: 4256.92D50
• In use/Tested By:
  • David on his 1991 VW GTI TDI swap
• Alternative:
  • stock 87° Thermostat
• Comments:
  • Low operating temperature is known to hurt MPG, but there is no solid proof that higher temperatures will improve efficiency.