We carry the '74-'89 style factory 911 thermostat. Superior to aftermarket units, this thermostat includes a pressure bypass valve. In the event the oil cooler loop gets blocked and cannot pass oil, the bypass valve opens allowing oil flow and protecting your engine from oil starvation.
This unit can be retrofit to all 911s from '65 to '89 and 914/6.
The '74-'89 factory thermostat is recommended for all external oil cooler retrofits (unless concourse originality is the key goal). The system works very well and the parts are readily available.
Check our External Oil Cooling Configuration Guide for fitment information to all 911s, 1965 to 1989.
Unlike aftermarket thermostats, the factory unit includes a pressure bypass. In the even of cooler blockage or excessive back pressure, the bypass opens to protect the engine.
The thermostat begins to open at about 185F and fully opens over by about 195F.
Check to confirm availability of used thermostats.