Originally Posted By: Turk
I've owned my 2003 GMC Sierra 1500 with a 5.3L Vortec since brand new.
It had nothing but 3k Conventional 5w-30 OCI's up to 63,000 miles.
It had nothing but 4-7k Synthetic 5w-30 OCI's up to the last fill.
Then, knowing the stout additive pack, and knowing I'd pull my heavy boat a lot, I thought what the heck: I filled it with Mobil 1 Turbo Diesel Truck (TDT) 5w-40 last Spring, close to 200,000 miles.
- On 5w-30: Each cold start for years (at 32F & under), the engine would clack like crazy until it warmed up, then it slowly went quiet.
- On this M1 TDT 5w-40 fill: Each cold start (at 32F & under), there is NO engine clacking.
I have repeatably started this engine in cold weather to prove eit's consistent.
It sits and sat outside for the past 5 years. It's 7F this morning and it started quiet as can be (and has all this season).
...and before anyone gets on this kick... I have had zero bias on engine weights.
Amazing.
Originally Posted By: Greasymechtech
Try the M1 0w40 for a run.
M1 ESP and HM is pretty thick for a 5w30.
And of course, Castrol 0w30 and 0w40..
I'd also consider other 5w40's like Rotella T6, Delo, Valvoline, Castrol...
Viscosity film thickness as a shock absorber.... or extra additives being utilized... Viscosity extremes... going too thick or thin never surprises me anymore.
Same oil filter?
My 6.0 in my c3 got m1,euro this change and not that the engine was really noisy before but now I can barely tell it's running.
I have a ton of euro spec stuff right now so now that I've heard the difference I'm going to keep with it.