I am not going to get into the mudslinging and name calling here, but there are a couple REAL “anal retentive engineering type” issues you should consider here and those are;
1) The tendency of Mobil 1 oil TBN values fall off slightly quicker during use than some other equivalent weight premium fully synthetic motor oils. Mobil 1 5w-20 TBN values start out with values of 2.70 to 2.75, while the values for the 5w-30 weights start out at 3.00 to 3.30. For comparison Redline SN rated 5w-20 has a TBN value of 3.00
2) The valve train design of the AJ-V8 engine uses direct contact bucket followers on camshaft lobes – that type of contact is similar to an older pushrod engine with a flat tappet camshaft. SN rated oil have reduced levels of ZDDP anti friction additives compared to the oils which were the factory fills in LS engines. The 2000-2004 LS V8 engines were factory filled with SL rated oil, while the 2005-2006 LS V8 engines were filled with SM rated oil. Mobil 1 High Mileage SL rated 5w-20 and 5w-30 oil have 1000 PPM phosphorus and 1100 PPM zinc compared to the SN rated oils with 800 PPM phosphorus and 900 PPM zinc values. Simply put the SL rated oils offer greater protection against valve train wear than the SN rated oils in the AJ-V8 engine.
Because of all of this, I personally blend about equal parts of Mobil 1 High Mileage SL rated 5w-20 and 5w-30 oil (that I buy at Wal-Mart in 5 quart jugs for about $26) when I change the oil in my ’04 Gen II LS V8 engine. I also use the slightly longer Gen I oil filter on my Gen II engine, even with the reduced clearance to the serpentine accessory drive belt.
As always of course, YMMV. Stepping way now to put on my flame retardant fire suit.
