ok, well I'd like to hear his reasons for switching. I know that no one has seen a difference in the 0w-40 vs 5w-40 but if you are going to be running the SRT in cold weather then I would use the lighter weight oil.
here is some info for the SRT Engineers chat last week
Please explain the oil specification of Mobil1 0W40 --
seems that 5W40 or 10W40 covers the same ground for most ambient temperature applications.
part 2: will SRT authorize or waive the 0W40 to allow use of Synthetic 10W40 or 5W40? (especially in Texas where the low ambient is 25 degrees F)
You are correct the only significance in the low end of the oil weight 0W vs 5W vs 10W is the improved performance in the very low temperatures. We certify for the entire nation so we pick the best product for use for everyone. Mobil has told us the 0W40 has the most stable additive package of the multivis synthetic oil group. In truth you can use any of the Mobil synthetic oils you have mentioned without concern. Dodge will not quibble with any of these selections especially for 25deg F low temps.
Initially our 6.1L were designed to use 0W40 Mobil 1, its on the oil cap and in the SRT's car manual. The bankruptcy brought about a falling out with Mobil 1, now all the dealerships are using 5W40 in the SRT 6.1L motor. From an engineering perspective is this change OK for the 6.1L? Why the change in viscosity? Thank you.
Yes the change in viscosity from the 0W to the 5W will only show up in very low ambiant conditions (-20deg and lower). The closest synthetic oil from Penzoil/Quaker/Shell available for all of our sales areas required this small change in low end viscosity. In truth any quality synthetic oil with 0-10W40 multivis oil will be fine for your 6.1L. If you are running it hard or in very hot climes use the 10W40 (or even 15W50 on the track). If running in very cold climes move it down 0 or 5W40.
Seeing that Chrysler isn't using Mobil 1 in the 6.1 Challengers, what weight and manufacture should we use. Just had the oil changed in my 08 Challenger at the dealer, and the receipt did not specify the weight or manufacture.
For our products direct from the factory we are filling our SRT engines with Penzoil 5W40 synthetic. Any quality synthetic wide range multivis can be used for continued service. Certainly the recomendations would include Mobil 1, Penzoil platinum, Quaker Qpower, or Shell Helix as quality synthetic oils.
I have used Mobil 5W-40 with complete success. The filter I would recomend is Wix 51515. The filter is about one inch longer but has the same micron rating as the factory recomended filter. It won't work on the 08/09's. They have a different thread.
I use to have a Corvette that I used Royal Purple in and did a dyno test comparing Mobil 1 and Royal Purple. RP picked up 8 horsepower. If you think about it that's really amazing when the only difference was the oil. It shows how much less friction/heat is being produced which not only translates to more power but longer engine life.
Interesting converstion overall, I've been using whatever the local Firestone Full synthetic oil is, Castrol I believe, for the past year. No problems at all and I live in the Seattle area so lowest temp is 20ish for like 2 days. I also ran at high speeds across half of Wyoming last summer when the OAT was roughly 100F with no issues...
most quick lube places will have single bottles of specialty oil that they can put in but it is hat a higher price. I've stuck to Mobil 1 and once I took my car to a quick lube place that carried what I wanted and that was a $90 oil change. However I have yet to find one that won't let you bring your own oil and filter and then it's usually about $15 for them to change it. That saves you about $25. The dealerships will use what ever the current factory fill oil is. I was Mobil 1 and then it changed to Rotella (Shell) and I'm not sure if it still is or not.
The biggest thing is to get 100% full synthetic in the proper weight and to get it changed regularly. I don't think the exact brand matters as much, more personal preference.