Does anyone measure their PSRU temperature? So this is weird, usually it would only be about 2-5degrees hotter than the inlet oil temperature. That was in Oct. I started to fly again in May and really the only thing I've done is switched to synthetic 20W-50, and my psru temps are 5degrees colder than the oil pan temperature now. Either the outside temperature of Florida, or synthetic , I have no clue what's going on. Took it apart ahead, don't see any obvious going on.

215 Oil pan

210 PSRU

195 Oil inlet

Side note, I did upgrade my oil cooler last week about 40% fin area, to a Setrab 34 row. Depending how you measure the 'core'. It dropped the overall temps about 10F, while taking off in 100F weather.