appreciate the info. i was told 15/40 ash free is what it takes. i will deffinetly look into the chevron oil. thanks again.jon111-- To protect your engine and all of the new emissions crap you have to use a low ash oil with spec API CJ4. Chevron makes a great oil called DELO 400 LE (Low Emissions) that will work for you.
API CJ4 is the latest requirement for low emission diesel vehicles. Your warranty probably requires it. I have 1500 miles on my new '08 and this is probably the oil I'll use.