I ran Mobil 1 full synthetic 5w30 in my 150k mile 3.8. oil pressure was consistent 60+psi cold start up, 30psi when at operating temp and 80+ when WOT. My rod bearings/journals have normal wear on them, even after 6k miles of beating on the motor with a M112 on top.

You should change to 10w30, it may help seal the piston rings against the cylinder walls and reduce your oil consumption. Doesnt hurt to try and itll be better on the engine if you get hit with cold weather.

 

So using 10w30 isn't bad for the motor even when it gets cold? Should I switch to Mobil 1 Full Synthetic instead of the current Castrol Edge High Mileage Full Synthetic? As far as I'm aware, the car has been using Castrol for at least the past 3 years, and I'm not sure what the benefits/downfalls of switching oils is. Is Mobil 1 good and what is it called exactly if I go to buy it? Just Mobile 1 Full Synthetic 10W30?

 

Also, what oil filter would you recommend and does it make a difference? I've always just used the typical FRAM's from walmart/pepboys with my car. I've read that K&N's or something are better because of some Anti-drainback valve within it? I have no idea. I also noticed there was a few different K&N's so I wouldn't know which to choose.

 

Ive used many oils over the years...Castrol in my Toyota, Kendall in my Trans-Am, and now Mobil and/or Pennzoil in my Mustang.

One oil I will NEVER use in anything is Quaker State. Worthless garbage. I learned from my father N law just what crap that one is. Foamy bastard oil.

 

It used to make a difference in brands of oil and filters. Now, as long as you stay with one of the main name brands they are very close in performance and offer little advantages over each other.