What is the best weight for summer

[ALS]

My owners manual recommends 10W30, 5W30, and 15W40 for use in my Turbo motor. I have always ran 10W30 but with the warmer tempertures I'd like to run a thinner oil for better mileage. I don't want any problems with running a TOO thin oil. Next change will be due somewhere around the mid to end of April so don't need to worry about cold temps. Would it be better to run the 15W40 or 5W30 during the summer.

 

[Audi Junkie]

15w-40 is heavier and is made of a heavier basestock. Cleans, reduces consumption and handles the summer heat better. Turbo diesels run on it. Chevron Supreme says "Turbo" on it's 10w-40 a fine choice.

 

[Swift]

Nothing scientific, but I run 10w/30 in the summer months.

 

[williar]

I agree with the 10w30, but, especially since your motor has a turbo, be sure it's a top-quality synthetic such as Mobil1.

 

[Mike242GT]

ALS:

Here's a curveball for you - how about Rotella T synth 5W-40? That's what I'm going to run in my two B230FTs this summer.