The currently vocal contingent has their minds made up about many of these subjects so I won't bother getting into those. But advertising is one we haven't explored in much detail on the site, so here it goes.
Yes, I have a healthy skepticism about the advertising claims of big multinational companies. Words matter and that's why they use ones like "up to".
I'm quite certain Pennzoil conducts a variety of tests during product development. They're a good company putting out good products. I'm also certain that the best results get cherry picked for inclusion in their advertising claims.
Here's an analogy for you. Television manufacturers for the past several years have been advertising higher and higher contrast ratios for their sets. 5, 6, 7 million to one and higher is typical.
Well guess what, actual measurements on those sets show contrast ratios below 10,000:1. Imagine that, the worlds largest and most respected consumer electronics companies (Panasonic, Sony, Samsung, Sharp, LG, et al) would use misleading advertising claims! I'm sure the numbers have some connection to reality, perhaps within one manufacturer's product line the model with 5 mil:1 does have better contrast than one with 2 mil:1. But the numbers themselves are nonsense.
Here's some verbiage from Mobil about my favorite product of theirs, 5W-40 Turbo Diesel Truck. I use it in my '03 Saab 9-5 Aero sludgemobile.
"Mobil 1 Turbo Diesel Truck reduces low-temperature sludge build-up and high-temperature deposits through excellent thermal and oxidation stability. High temperatures pose little threat as Mobil 1 Turbo Diesel Truck fully synthetic motor oil maintains its viscosity and has enhanced oil film strength, which helps to reduce engine scuffing and bore polishing. It also provides wear protection and reduced oil consumption with its shear stability."
They don't call out any percentages, but my inner skeptic asks "reduced oil consumption compared to what?" In what conditions? Enhanced oil film strength? Enhanced compared to what?
Castrol still uses this old goodie for GTX:
"Engineered to provide maximum protection against viscosity and thermal breakdown!"
Maximum? That implies there is is no possibly superior product. dunno if I believe that. They also say:
"Superior deposit protection", as shown by the Sequence VG sludge test. Wait, how can that be? That's the same one Pennzoil cites. They can't both be the best can they?
jeff