im changing my oil tomorrow morning and wondering what you guys think is the best oil to put in. thanks

 

20w-50 castrol

 

i'm using the same one.

 

same here

 

I use Mobil 10-40

 

i guess depends where you live. me being in florida i use a lower wieght penzoil 10 w 30 .

 

Why use thinner oil in hotter weather?? How insideous.

 

I used 10W40 until I passed ~100,000 miles.
Then I went to 20W50.
At >200,000 - 20W50 + "motor honey" to suppress smoke.

My current turbo @ 90,000 - 10W40 for one more change.

 

Do oil brands really matter that much. Don't all these conventional oils come from the same crude?

 

huh. thats a good point.

 

i live in the desert, and my car has 105k miles. I'm running 10w30 mobile non-synth. Should I up or change my brand and weight for my next oil change?

 

They come from different stocks, but they must all meet the same specs to get the same API rating.

Some have a little less residual ash, and that bothers some owners but not me.

(I had a great link on the subject, but it's down now)

 

I use Castrol GTX 20-50 in my GXL

Never really experimented with synthetic but i hear it's bad...bad for Rotary.

 

I just changed.
Havoline 10/30.

 

Some synthetic oils don't like to burn, & some others are OK in the oil injected rotary.

 

20W50 is the norm around here for NA's and TII's since these cars are getting old and rotaries run hot which thins the oil. if you live in a warm climate 20W50 should be a good idea...castrol is the most common choice around here too. for some reason it's been a preference at our shop for years.