You can buy Delvac 1 at lots of truck stops. Go onto Mobil's website and you can search for stores in your area. Also, the Mobil 1 truck and suv is sold at lots of wal-marts and such. Its supposed to be the same thing as delvac 1. I run this oil in my 96' grand cherokee with the 4.0 and it seems...
my 4.0 jeep has about 100k on it and i recently switched from penz 10w30 to rotella 5w40 syn. I noticed a huge increase in idle noise. Im not sure what the noise is coming from, but it sounds like the valves or piston slap? whaterer it is, i dont like it ant want to drain and try something else...