Originally Posted By: sdude2k2000
NattyBoh - I don't mean to sound disrespectful when I say this, but just last week several 6.0L owners advised you (in another thread on the first page of this sub-forum) their thoughts and feelings multiple times in regards to what they have seen to be the best oil for a 6.0L... a 30-weight. I'm not sure if you just don't trust us (and the updated manufacturer recommendations), want to hear a different answer, or are trying to over-analyze every aspect of oil for your truck... but I can't imagine the recommendations changing.
Delvac 1 5w40 is a fantastic oil for some applications, and at $16.99/gal it's a great buy, but in your 6.0L it will exhibit the same tendencies of all the other 40-weights. SHEARING. You will get nowhere near maximum return-on-investment with it... your local climate is well within the 30-weight spec recommendation by the HEUI manufacturers... and based on RoadRunner's extensive UOA history, I could even make the argument you won't be getting the best protection either. If you want to run a full synthetic, Delo 5w30 is a well priced option. Delvec 1 LE 5w30 is another option, but may be more expensive.
Again... I'm not trying to hound on you, but last week you wanted to run 15w40... now you want to run 5w40....... are we missing something?
Hey man,
I do remember that, but I seen it with my own truck... I was running 10w30 as per RoadRunner's suggestions about a year or so ago, and I noticed LOWER ICP pressure. Yeah... Hard ot believe, but weight is weight and that ICP did lower a bit when I was running 10w30. So that was my reasoning for running the 5w40. I understand it shears, thats old news. I have my own personal UOAs to see that, but when I seen the ICP lower slightly, that was my go a head to run 5w40.