Testing Primary oil thermostat 1975 2.7

[rickpollman]

I have removed the engine from 1975 2.7 do to overheating ahd trying to test thermostat how should this be done

[75 911s]

Rick, the on-board T-stat in the so called "triangle of death" area (named so because of it being a notoriously leaky area at the top of the motor) can easily be removed and placed in a pot of water on the stove. Heat it up with a thermometer next to it and watch when it hits 170+. It should open at 185 degrees Fahrenheit if my memory serves me.

2.7s have a bad reputation for running hot. In my opinion, it is mostly due to the unfortunate omission of a front mounted cooler. The bean counters of Porsche yesteryear decided run them hot to combat emissions, meanwhile the poor motor is melting. The mag alloy case was a bit softer yes, but running them that hot was a recipe for disaster.

Your t-stat is likely fine. You might also have a timing issue, if that is off your motor can run way hotter than normal. Has the timing / dwell been set? Also check your oil level. Too low and it can run a bit hot too.

You can also do what many 2.7 owners have done and add the front mounted cooler. This will let you run below 250 pretty much all the time. Without the front cooler, you're going to spike in summer or with spirited driving to 250 rather quickly.

[Jack Stands]

I’ll second the recommendation on the front cooler. My 2.7 never overheated once I put in the cooler, even though it was modified significantly for more horsepower.