Originally Posted By: Clevy
Originally Posted By: Shannow
Given that 10W30 is obsolete, how can it be "new and improved" ?
Personally, I think it's great...still has to have HTHS comparable to A3/B4
Hehehe. Awesome. I'm thinking caterham wasn't considering diesels when he posted that. I'm sure he'd approve though. This goes along with his thin oil mantra.
Not that a single torn down engine can be considered absolute proof that 10w-30 isn't too thin for big diesels.
If I made my living hauling I'm not sure that I'd waiver from the accepted norms when it comes to lubricants. 15w-40 has been the benchmark for decades.
Clevy, CATERHAM fully understands J300 and it's history, so this is no surprise...except he keeps calling RL 20s "really 30s", and the like.
SAE 30 was always just straight 30, it had an HTHS in the 3.5 range, and always served the industry well...15W40 was unusual and new, and they needed the 40 part to counteract the temporary and permanent shear thinning that occurred by chasing the 15W, and VI part of the equation.
Look at the early J300 when they finally included HTHS, and there was a serious difference between the PCMO 0W, 5%, and 10W 40s, which had minimum HTHS same as the xW30s...while the HDMO 15W, 20W, and 25W40s had an HTHS in keeping, and slightly higher than a standard SAE30.
This new 15W30 is, in my mind, and I'll posit same, a demonstration that SAE30 was the correct lubricant for the OTR diesels of the day, and that modern VIIS, PPDs, and whatever can now give you the operational protection that an SAE30 did back in the bad old days, without requiring artificially high KV100s to counteract the temprary and permanent shear that the 15W40s had to combat.
It's silly, and TGMO does it to have an overly high KV100 for a given HTHS, just to give a great VI.
IMO, 15W30, in a modern fay formulation is going to be as solid as SAE30 was "back in the day"