40 vs 30

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Srt8 charger. We got rotella 5w-40 for it, the rotella bottle says it meets sm automotive so I think this is a good choice. However, the RT use 5w-20 and the v6 5w-30. Why? Is the 5w-40 just for show? LIke so that mobil can endorse it? There aren't too many 5w-40 oils and there is only 1 OW-40, mobil's, that I am aware of. When the warranty is up, can we go to a 10w-30 synthetic or 5w-30 synthetic or will this hurt our motor ? Thanx. Just seems wierd that the srt8 needs the 40 weight but the rt needs a 20.
 
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Follow your owners manual for oil choice versus the temperature of the climate you are operating in. Your manufacturer knows best. \:\!
 
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They sell so few of the SRT8 versus the R/T that they are not concerned about CAFE, they know the SRT8 will get bad mileage and know it is a higher performance engine so they won't bother specifying a light oil for it. You may also notice no MDS system on the SRT8, either. I think a 5W-40 HDEO, Mobil 1 0W-40, or even something like Mobil 1 10W-30 would probably do very well in that engine. The Mobil 1 0W-40 may be specified just to ensure that the correct oil goes in that engine, and it is likely any other oil that meets the same Mercedes specifications as Mobil 1 0W-40 would be suitable.
 
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 Originally Posted By: rangerfan24
Srt8 charger. We got rotella 5w-40 for it, the rotella bottle says it meets sm automotive so I think this is a good choice. However, the RT use 5w-20 and the v6 5w-30. Why? Is the 5w-40 just for show? LIke so that mobil can endorse it? There aren't too many 5w-40 oils and there is only 1 OW-40, mobil's, that I am aware of. When the warranty is up, can we go to a 10w-30 synthetic or 5w-30 synthetic or will this hurt our motor ? Thanx. Just seems wierd that the srt8 needs the 40 weight but the rt needs a 20.
There's nothing strange about it. Different engines, with different characteristics. If you want to experiment with different oils, I'd wait until the wty is expired, and I'd do UOA to see if you can spot any problems cropping up with non-spec oil. =======================================================
 Originally Posted By: rangerfan24
I have a feeling mobil is paying them to know best a certain way maybe. dunno
The most important statement here is "dunno". Which translates to "I do not know". This comment is right up against the line of improper, and the only reason it's not across it is that you qualified it with "I have a feeling..." It's not about EM being a sponsor, by the way. It's about accusing any person or corporation of unethical or illegal conduct without any real evidence to support the statement. I can't imagine what either EM or Chrysler would gain through the bribery arrangement you suggest. EM already has a huge slice of the market. Chrysler has enough problems without inviting investigation, or by spec-ing an oil that's not chosen for its ability to protect engines. Let's keep it clean and not be making accusations or even insinuations unless such can clearly stand up to careful examination.
 

rangerfan24

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Whoah. Chill out man. 1st off, no ones accused EM of doing anything wrong.Marketing is marketing. Do you think EM gets endorsed by major auto companies, for free? Chrysler just happens to spec it, along with other GM high performance cars? Sorry man, just don't work that way in this world. EM is allowed to market how they market, its not illegal or unethical at all. So you are wrong there, just plain wrong. Second, nothing was improper in my post. All I was investigating was wether or not a 30 weight would just as well adequatelly protect the motor, thats all. So before you go scolding people like their your children, think. If you dont like my post, dont reply. Had you said that 0w-40 was chosen on its performance, I would have no problem. But you assumed I was bashing M1, when I was not. By the way, my two toyotas have m1 5w-30 and the minivan has clean 5000. And no I wont be having a beer with you. Thanks.
 
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 Originally Posted By: rangerfan24
Srt8 charger. We got rotella 5w-40 for it, the rotella bottle says it meets sm automotive so I think this is a good choice. However, the RT use 5w-20 and the v6 5w-30. Why? Is the 5w-40 just for show? LIke so that mobil can endorse it? There aren't too many 5w-40 oils and there is only 1 OW-40, mobil's, that I am aware of. When the warranty is up, can we go to a 10w-30 synthetic or 5w-30 synthetic or will this hurt our motor ? Thanx. Just seems wierd that the srt8 needs the 40 weight but the rt needs a 20.
5w-20 is speced for 5.7L Hemis with the MDS so it operates properly.
 
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