[drolston]

Wanted to replace tired old stock 160 degree thermostats with 170 degree units. Learned from this site that the Stant 14157 for a Subaru would fit. Had to clean up the inside of the radiator hose connection on the Offy head, but they do fit. Tested them in a pan of water with a candy thermometer and they both started to open at just under 170 degrees.

Very disappointed to see the temperature gauge go well past the hot mark (200+ degrees) sitting at idle in the garage on an 80 degree day. Then the temperature slowly dropped to about 170 degrees. Evidently the water temperature at the gauge sensor has to get to 200+ before the water temp up in the radiator hose neck gets to 170! Unacceptable. Nothing to lose, so I drilled two 5/32" holes in the thermostats (see picture) to let some water flow through the hose neck. That did the trick; the temp now comes up to 170 and stays there without overshooting. At least until the lousy cooling design of the 39 - 41 cars lets the temp creep up at idle (slower rotating crank mounted fan, too low on the radiator and too far from radiator, with way too much area for air to flow around the radiator instead of through it).