5w30 vs 0w40 Mobil 1

[ile2010]

I know that oil has been discussed ad nauseum on the forums, and I've read that both weights meet the GM standards. Please forgive my ignorance, but what is the difference between these two weights? Pros and cons of each? My Saab mechanic has recommended going with 0w40. The car has had 8,000 km 5w30 changes with the previous owner.

I plan to change my oil every 8,000 km. I know the Saab interval is 16,000 km, but I just cannot take that chance.

[Burnsside42]

Reccomended oil change interval is every 5-8K on 0W-40 oil. I do it every 4K on my own cars personally.
Clean oil is better then no oil in my opinion. I use what's available or on sale - and full synthetic.

As long as you change it and you are checking it periodically - do what works for you.

0W-40 has less friction then say 5W-40 or 30

meaning it's thinner and does not change consistency as much as a heavier thicker oil would like 5W or 10W and so on.

Learn/Read: Motor oil - Wikipedia, the free encyclopedia

[nordwulf]

Mobil 1 5W-30 neither has the GM spec nor the European A3/B3 spec which is recommended for the 9-5 2.3T. So if you want to stick with Mobil, only use the 0W-40. Unless there is a difference for Canada.

Castrol Syntec 5W-40 is another good alternative which I have been using in my previous 9-5's.

[ile2010]

Thanks Frank, I guess that's the reason why Mobil 1's website tell me to use 0w40 for my Aero. I know that the previous owner used 5w30 and that shouldn't matter too much, but I want what's best for my car.

[Brad Lauzze]

'04+ Aeros all got the Mobil 1 0W-40, which is what I run in my car. One of my old co-workers at Saab ran it in his '02/'03 Aero without issue as did a number of our customers. Like it was said before. 5-8k is fine for oil change intervals if that is what you are using for oil. I usually go 4-5k on my own cars.

[ile2010]

Just to clarify, you're speaking in miles, correct? My interval is 8k in kilometres, which is 5k in miles.

[Brad Lauzze]

Yes, miles.

[pc4033]

Mobil 1 5W-30 neither has the GM spec nor the European A3/B3 spec which is recommended for the 9-5 2.3T. So if you want to stick with Mobil, only use the 0W-40. Unless there is a difference for Canada.

Castrol Syntec 5W-40 is another good alternative which I have been using in my previous 9-5's.

Frank, It seems mobil 1 0W-40 and high mileage 10W-40 oil meets the requirements of A3/B3, which means we could use it? My saab 9-5 is about 120K miles. Can I use 10W-40 in summer? Just can't find castrol 5W-40 near my home.

[rpiereck]

If it meets the standards then yes it's good for use. I was using Lubro Moly 5W30 because it met the A3/B3 standards (even though it's not an issue with the NG900, but I wanted to be safe rather than sorry). I'll be checking the Mobil 1 in the local store for A3/B3, as it's cheaper.

[ile2010]

Frank, is Castrol Edge 5w40 just a rebrand of the Syntec? I don't see Syntec around here anymore. The Edge is $32/5L on sale, which is an excellent price.