11-13. There's a viscosity chart and you have to squint to tell that it goes below 0F, but the Factory Service Manual mentions -4F.Thanks all for your replies and suggestions. This thread sort of sums up my confusion about this topic, as we seem to have a 50/50 split on what I should do.
Thanks, I already practice this with the current fill. As someone mentioned, that might be with M1 due to it being a bit on the thin side.
I'm worried because I want to fully understand them. I've read up on what those values are measuring, so I understand the definition so to speak, but am a bit unsure in terms of real-world use, specifically for my application. The EJ isn't anything special but not all engines are created equal. Just trying to prolong its life the best I can. Good point about the battery, I should be replacing mine soon.
Red Line lists the CCS in poise instead of centipoise so I went with that. Thanks for explaining the testing temp difference, that makes a lot of sense.
I'm not sure that's true for an EJ, especially in the summer. As in most cases with Red Line, I had to order it online. I may be able to return it, but I don't think it'll make economical sense.
Thanks Dennis. Firstly yes, I'm referring to the High Performance line. My factory battery is getting pretty tired, as I've noticed sluggish starts on a couple really cold mornings. I'm not worried about the car starting due to viscosity, but about the oil getting to where it needs to in time. As much as I want to just do it, I may hold off for the summer. I don't know.
I've taken the manual recommendations with a grain of salt but hadn't come across this. Do you remember what section it's in?
Before I sold my Forester, I ran 10W-40 in the summer (mainly due to high consumption) and that sometimes continued into the winter depending when I needed to change the oil. I did usually top up with 0W-40 during the winter and would usually just use 0W-40 if I was changing late fall/early winter.
If I didn't burn through two quarts in ~5k miles, I probably would've stuck with 0W-40 year round. I do recall Dave at Red Line recommending their 5W-30 in turbocharged EJ's that specced up to xW-40. After my last factory battery lasted me less than two years, I ditched it even though it was under a pro-rated warranty and went with a more powerful Interstate battery. I left a map light on all night in single digit temps (twice!) and didn't have any issues starting the next day.