Greetings:
In researching the issue of what oil (synth versus dino) and what weight (5w-30 versus 10w-30) to use I have decided to run Castrol Syntec but am debating what weight. I have a 2004 Chevy Avalanche with a 5.3L V8.
I see that the 10w-30 has better High temp/High shear numbers than the 5w-30 (3.1 versus 2.9), however both are in the SAE range of min 2.9 to max 3.5 (ACEA A1, A5, ranges as well).
My question is does a HT/HS number of 2.9, do an adequate job of protecting the bearings, etc. or would it be worthwhile to go to a weight with a higher number? Both Syntec weights pass the GM 6094M (light truck) and GM 4718m (Corevette) standards. Also, it is not particularly cold where I live (generally ambient temp in winter does not get much lower than freezing) but the manual states a preference for 5w-30.
I elected to go with Syntec as the numbers look good on paper and with the UOA's I have seen. And for what I do, wear protection seems more important than temperature tolerance, hence Mobil1 made a very close second. Yes, AMSOIL is a great product, yes it has great numbers, yes it has a cool name, but the product with the great numbers is not API certified and the potential warranty issues rule it out for me.
Thanx in adavance.
Bob W.
In researching the issue of what oil (synth versus dino) and what weight (5w-30 versus 10w-30) to use I have decided to run Castrol Syntec but am debating what weight. I have a 2004 Chevy Avalanche with a 5.3L V8.
I see that the 10w-30 has better High temp/High shear numbers than the 5w-30 (3.1 versus 2.9), however both are in the SAE range of min 2.9 to max 3.5 (ACEA A1, A5, ranges as well).
My question is does a HT/HS number of 2.9, do an adequate job of protecting the bearings, etc. or would it be worthwhile to go to a weight with a higher number? Both Syntec weights pass the GM 6094M (light truck) and GM 4718m (Corevette) standards. Also, it is not particularly cold where I live (generally ambient temp in winter does not get much lower than freezing) but the manual states a preference for 5w-30.
I elected to go with Syntec as the numbers look good on paper and with the UOA's I have seen. And for what I do, wear protection seems more important than temperature tolerance, hence Mobil1 made a very close second. Yes, AMSOIL is a great product, yes it has great numbers, yes it has a cool name, but the product with the great numbers is not API certified and the potential warranty issues rule it out for me.
Thanx in adavance.
Bob W.