Originally Posted By: OVERKILL
The SRT 0w-40 is designed for the SRT engines, all of which have exceedingly short oil change intervals. My OLM came on telling me to change my factory fill at 8,900Km (5,500 miles). Subsequently, I would not whimsically use it in other applications for extended OCI's without a complement of UOA's to support it going the distance.
I agree. But then, I don't even use it in my SRT, I use M1 0w40 which has a much longer track record. A lot of my bias against Pennzoil 0w40 SRT is that it just seems like it was slapped together to fill a 0w40 requirement that was left vacant when FCA switched from XOM to SOPUS. In fact the first year of the SOPUS alliance, Pennzoil Ultra 5w40 was factory fill in SRTs because Pennzoil didn't have a 0w40 in the premium lineup. PU "SRT" 0w40 seems like a very ordinary, standard-duty additive package that was translated over to a 0w40 grade. Its even got SN 30-grade-like levels of phosphorous and zinc rather than the higher levels allowed for a 40 under SN (yes, I know there are other ways to skin that cat and SRT engines don't need extremely high doses anyway). Then there's the whole fact that it was THE LAST PU Grade to get switched over to their hyped-up GTL base stock. Dead last... and this is supposedly a high-performing oil??
To be fair, I am speculating a lot on its formulation, as we all have to do since the oil companies hold things close to the vest. It may be good oil. It may be VERY good. But given the fact that its either very hard to find or priced much higher than M1 (usually both in my area!), that VOAs and UOAs on it don't look better (and maybe not as good as) M1, and that M1 has such a strong reputation there just wasn't any hesitation for me. Even before warranty was up, M1 0w40 went in the SRT-8. And lest anyone think I'm some kind of XOM homey, my Jeeps have always gotten SOPUS products.