Originally Posted by Virtus_Probi
I have a '14 FXT with an engine that is similar to the one in the WRX and I think the highest oil temp I have seen on my monitor was 231F (111C)...this was a while ago, so my memory might be faulty.
I was running a higher HTHS 5W30 (M1 ESP Formula) at the time and that was making my general oil temps run a bit higher than usual.
Temps were in the mid 90s (~36C) that day and my car was carrying a decent load for a family trip, but I wasn't towing anything. I'm not sure if this affects cars in the same way it does humans as far as shedding heat, but it was also quite humid that day. The peak temp came when I was passing some slower cars during a long climb in an area of low mountains...this was highway 101 up in western NH and there are only short lengths of that road that are 2 lanes for passing, I made sure to take advantage of them and get ahead of the semis and dualies with horse trailers and such. Pretty shocking for New England, but the slower drivers were actually pretty good about moving over to the right and letting others pass on 101...move it over to 93 and there are so many drivers who love to hang around in the left lane, poke around, and just plain be in the way.
Hitting 220F (104C) in the summer with SN/GF5 type oil is pretty common for me.
That is very similar to what I see with my 2015 FXT (same engine as WRX).
The highest I seen is 110 C while in sport sharp and paddle shifters in high RPM in the summer (25 C ambient).
Right now in NB, Canada (-10 C ambient), I see around 92 C on the highway and 80 C in the city.
I went on a ride with a friend that has a 2019 impreza and the temp on the highway was 103 C for a 4 hour trip. The little FB20D seems to run hotter than our FA20DIT.