i want to change oil at the local garage. what oil should i use--(i like castrol) and the manual calls for10-30 or 5-30 or 10/40. i think here in this heat i should use 10/40??? should i use reg. dino oil or a blended oil or go to full synthetic oil--------i am an old guy and rather conservative. i live in florida and our temps are in the high 90s and very humid. would appreciate some opinions from users on this type engine. (2001 S type 4.0)----DO NOT want the dreaded "OIL DISCUSSION"!!! just what you are using and why. thanks doug

 

5w-30 synthetic every 5k miles.

i have an str though.

 

For your climate some good choices might be:

15W40 Castrol Diesel
15W40 Shell Rotella T5

They are compatible, targetted to high wear environments, offer better film thickness to account for your hotter climate.

They are both conventional oils.

Humidity has little effect on engine lubrication ... just human beings and cats of the furry variety

Oh, and in reality ... almost any major brand oil will do the trick just fine as long as you keep the oil level correct and topped off. eg. castrol, valvoline, shell, mobil, pennzoil(shell), quaker state, even supertech or napa.

 

Use the brand you like and the viscosity that the owner's manual recommends. Arguing whether synthetic or regular is better is futile- the engines will still be around long after the remainder of the car has died, no matter what is used.

 

Mobil 1 synthetic 5w30 with 1 qt of Lucas Oil Stabilizer.

I tryed it on a track car several years back and it free'd up a few extra whp on the dyno and after 10 passes showed much less ware n tear on the internals.

To each thier own.

Edit: I've run 5w20 as well on a 2.0 with 450whp (on E85 i might add), but all my big V8's and street cars 10w30 less it's really cold or really hot.

 

Mobil Synthetic. I actually even use it in my lawn tractor. Works for me.