And on we go...
GR8 ASP, I see the issues similarly and don't think we are far apart. Perhaps it's that my comments tend to favor the user and yours tend to favor the OEM requirements. I'll try to be balanced in future commentary.
sniper1, a few questions for you:
1) what oil is recommended in your owner's manual? (viscosity and API rating?)
2) what oil do you use today? (viscosity and API rating)
3) how did you decide to use the oil in #2?
If you can't share the answers to #1, 2, and 3, then you aren't recognizing much of what has been discussed and we aren't having a constructive conversation. And I'll have to take back my $50/qt oil full engine warranty offer to you.
Also, I want to make sure you understand that the OEM issue with diesel oils is not the viscosity grade of SAE 15W-40 as you keep mentioning, but the level of an one additive in the formulation. There are SAE 5W-40 diesel engine oils and although hard to find, SAE 10W-30 diesel engine oils. Based on your comments you would use an SAE 10W-30 API SL engine oil, even if it additionally met the diesel criteria? Would you use the Mobil 1 0W-40 that is recommended in the newest Viper? (It has diesel performance.)
![Roll Eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
![eater :eater: :eater:](/vca/styles/default/xenforo/smilies/eater.gif)
Still waiting
HSSSSS, the Mobil 0W-40 and a full diesel oil are getting close; the diesel oil probably has more dispersant to manage the soot levels reached in the big diesel engines. Unless you are going extended drain, the performance of either is very similar and is personal preference.
Greg, about $5 more of the precious metals in a catalyst would also take care of the "poisoning" problem. And actually, the catalyst doesn't suddenly stop working, the light-off temperature rises. That means it has to get hotter before the catalytic activity begins. Because the Federal Test Procedure for measuring emissions has a significant weighting on cold start, if the cat doesn't light off within seconds, it will "fail". So yes, a "fail" means 10 seconds of cold start unconverted emissions vs. a "pass" of only 3 seconds of cold start unconverted emissions.
Darbgnik, not that I want to screw a car company, but if you suspect the dealer would take an oil sample, just change the oil before going in. There isn't any reverse analysis of the used catalyst that would say the oil used had "too high" ZDDP and instead the conclusion would be "high oil consumption." Arguably an oil with more ZDDP would show less engine wear, therefore have lower oil consumption, and have less chance to affect the catalyst... a circular chicken-egg argument.