There are many oil weights available. The weights I see good results in LS based engines include: 0w-30, 5w-30, 10w-30, 5w-40. These are the most common I see with good results. There are many differences between each brand and how they are labeled. One thing to watch for is if you want a synthetic make sure the "synthetic" oil you are buying is actually a synthetic.

Ken

 

I figured a lot of you guys would be running synthetics but from the responces, most are using conventional

 

Mobil 1 Full synthetic here along with a Mobil 1 or K&N Filter everu 5,000 miles. Going on 153K now and still runs strong and doesn't burn oil.

 

I use mobil one high mileage back when it was running. The new 408 will have conventional for the first oil change then switched over to royal purple synthetic for the remainder of its life. Amsoil is good stuff too.

 

i use german castrol. 0w30

 

has anyone tried this mobil 1 15,000 mile formula yet? im kinda uncomfortable with it. my truck has always gotten mobil 1 10-30 but the parts store dosent have the old stuff anymore. its time for an oil change too

 

Amsoil 2000 0W30. I want a good cold temperature flow to the turbo and it gets cold here in the winter. Baldwin or Amsoil SD filter.

 

mobil 1 synthetic here.. 10w-30 or 10w-40
change it every 4-5k miles...

 

I've been using Mobil1 synthetic w/ AC Delco PF59 filters since my truck's first oil change at about 675 miles. I usually switch between 5w-30 in the winter to 10w-30 in the summer...even tried the 5w-40 "Truck and SUV formula" just for poops and giggles. I change the oil religiously, every 3 to 5 months, which is usually less than 3k since I've been working fairly close to home. Here's a peek under one of my valve covers at 39K, and again at 44K:

 

The book that comes witht the truck says that you should never use anything other than 5w30...

I'm currently using Mobil Clean 5000, 5w30

http://www.mobiloil.com/USA-English/...000_5W-30.aspx