Guys,

Last year, once I bought my Forester with EJ205 and installed the AEM oil pressure gauge, I used Mobil 5w30 Truck & SUV. Its 100c viscosity was around 11. I remember on a summer hot day when I stopped at a red light, tranny was in D, and I was that the oil pressure went down to 10psi. If I moved selector AT to P and the engine idled, the pressure went up to 18psi.
I switched to Pennzoil Euro 5w40 with its viscosity of 13.3, but when its hot outside and I am waiting on the red light with D + Brakes pushed, the oil pressure goes down to 10psi as well, not often as it was with 5w30 Mobil, but... when the engine is idling, pressure is 20-22 psi.

Does 10pst look concerning when I am stopped at a red light? Should go for an oil with 14+ viscosity (@100c)? Thank you.

 

I'm sick of posting this

Go for 10w40 or greater.

 

@1509joe Thanks for posting that. I am not using 5w30 any more. I am concerned about seeing sometimes the oil pressure of 10psi - is it ok when automatic tranny is in D + Brakes applied + When it is 25+C outside ? pressure is by 20psi when idling.

 

When your in Drive it will drop your tickover a little. The oil pressure switch is ridiculously low 8psi iirc. Don't know how cold it gets around you But I would run 10w/40 fully synthetic at least and see how you get on. In the summer you could try 10w/60. 5w anything is only emissions bull****.