Mitaka

Both the HEMI engine and the Honda Hybrid reccommend the 5W 20. Why is that. I have a ton of 0W 40 and would also like toalso use it in my other cars. Is that a problem?

audilvr

5-20 motor oil was specified for fuel efficiency and if higher temperatures warrant it where you live, I am sure you can use your higher viscosity motor oil.

I've always like using 5W-30 Mobil 1, and now use the extended interval (15,000 mile) version for my A8. I don't bother to use it in my wife's Explorer, because she only drives 10,000 miles per year max-- in this case I use mobil 1 and change it at 5000 miles. This is still probably overkill given the capabilities of a decent synthetic motor oil. Incidentally, the Ford Explorer manual specifies 5W-20 also.

Be careful and don't set yourself up for a warranty denial if you're under the manufacturer's warranty. You paid a lot for the warranty in the price of the car.

ivans A8

SAE 0-40 is more of universal oil which equally great for summer and winter. SAE 5-20 will not perform so well in a high performance applications or under extreme heat (if you live on the south, I would avoid 5-20). I use Mobil 1 5-30 in my A8 and drive all year around. Notice however I live in winter-cold Alberta, where we can get occasional -35 during winter months. Mobil 1 SAE 5-30 still flows freely @ -42C, which is more than I will ever need.