What is the best oil to be using, i have a 99 s70t5 with 120k miles.. right now im using castrol synthetic 10W 30.. and i live in southern CA. Seems to be working great just wanted to see if anyone uses something different.

 

I use castrol high mileage oil.

 

If you change your own oil like me for 5 cars, I choose whatever is on sale.

Now having said that I only use synthetic or semi for the S70T5. I think the oil change cycle is more important that the oil used. I change regularly at around 5K with the synthetic. Probably 3K if it has semi in it.

using 10/30 is great in CA. In MI in the winters I use 5/30.

 

I'd agree that the interval is the most important thing. Prior to this S70, I've always used Castrol non-synth (with the exception of a Porche 911 I owned for awhile). However, it's my understanding (could be wrong) that if you have been running non-synth oil and have a higher-mileage car, it's probably better to stick with the non-synth. In my case, the previous owner has used synthetic since 20k miles (I've owned the car a few weeks), verified by the service records. So, I guess I'll keep using the synthetic. I also use the high-mileage oil. It's funny though how I used to agree that 75k miles was high mileage. My brother drove his Volvo for 250k miles. Now that's high mileage!