Originally Posted By: Garak
Originally Posted By: PeterPolyol
10w30 is very relevant to me in my search for high quality synthetic engine oils that are built with cold flow properties as a last priority. I won't always want this in my locale bc winter, but I do want it whenever it's not below freezing.
I can't think of many scenarios where I'd consider Castrol Edge 10w-30 SN/GF-5 over Castrol Edge 0w-30 A3/B4 (well, the 10w-30 comes in 5 L jugs which are cheaper than 1 L bottles, but you catch my drift).
IDK about the examples you chose, but if there was a Castrol Edge 0w30 with absolutely no VMs, it might not be a 0w anymore, and whatever the cold rating would be for that 0w30 sans the VMs would be of no concern to me if it met the HTHS and KV on base oil alone. The quality of a 10w30 synthetic depends entirely on the blender. Some prefer to use straight synthetic high VI bases and some choose to cheap out on the bases vs the rest of the synthetic line, still resorting to high VM content in low quality base oil for narrow spread grades. Which road the blender takes makes all the difference.
Shannow, just out of curiosity what do you mean by you don't want a 15w40's HTHS? Too high or too low? If we're on the same page, then too high? I personally like the 'North American style" ILSAC 10w30s that Garak talks about vs a diesel 10w30, at least in my high-RPM NA gasser, bc the HTHS is lower than HD 10w30s (eg 3.1 vs 3.5?). ILSAC 10w30 is a fine choice IMO as a replacement for CAFE grades- (generally speaking) they're not too draggy and probably not too adulterated by VMs. Of course this only applies to products from blenders that choose to make a quality ILSAC 10w30 and not economise the grade out of disdain for it. Also notable, the recent demands on ILSAC 5w30 has undoubtedly pushed the entire grade into a much more robust version of what it once was ten, fifteen years ago. Sometimes (often times now?) a 5w30 will be blended with more synthetic, higher VI basestocks just to meet demands and new specs like Dexos. So it's not always a rule that a 10w30 of the same product line will be of significantly more robust than the 5w30 variant, but it's still very well possible.
Garak, it's not at all surprising that CT and other retailers in the Skatch have no shelf space for 10w30s, quite expected really. In the GTA 10w30s of all kinds are on the shelves. When Wal Mart has blowouts on oil, they stock 5w30 and 5w20 in winter and 5w20, 5w30 and 10w30 in summer. I was very excited to grab a couple jugs of the GTL-era PYB 10w30 (the one with an allegedly stupid NOACK of 4). There's even a bit left outside in the cold. I shook it during -20C and it sloshed!