What difference does 5w/30 make in the Hemi vs 5w20

JTK

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I'm currently at 57500mi on my 2019 Ram 1500 classic w/ hemi and have been running synthetic 5w30 at a ~5K mile OCI since 15K miles. I have no idea if it's going to make a difference or not. My fuel economy is still very good for this class of vehicle.
 
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I have the same truck as the op. I typically rum the recommended 5w20, but i did try 5w30 for one oil change. I noticed two things: first, the mpg dropped about 1/4 to 1/2 mpg, but that could be do to driving style, outside temperatures, etc. Second, lifter clatter on startup happens intermittently, but it was a lot more often with the 5w30. Switching back to 5w20 lessened the clattering.
Based on what I’ve read recently, i may go to 0w20 on the next change as we’re coming into winter. Not sure.
 
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I have taken care of a friends 2020 Ram 1500 5.7 for a long time using whatever 10w30 he buys on sale. I don't bother recommending anything different as he does not care enough to listen and it's not a topic worth arguing over. He has never thrown a code. I'm not saying there isn't some oil far enough out of spec to throw a code but I can tell you that 5w30 won't do it...
 
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I can see no difference in anyway between the QS 5w30 I used and the M1 0w20 in now.
Oil pressure and temp is the same. No codes or anything with the MDS. Sounds and feels no different to me. Same truck mines a 2020 classic Hemi.
I
 

ZeeOSix

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My point was: the greatest differences in viscosity will be during the warm-up period. Depending on how long it takes for your engine (and environment to warm up), the differences between the two could be negligible.
2 cSt at 100C is a pretty big difference in engine protection headroom.
 
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So my commute is the Kancamagus Highway so my commute has a 2000+ foot elevation gain in about 15 miles hence why I'm feeling like having a heavier oil in the sump would be better when I'm doing that several days a week during the summer at 80-100+ degrees. I'm not 100% sure if my motor has a dedicated oil cooler line either and it takes 7qts
I think your looking to be convinced that it’s ok to move up a weight.
If I were you I would just use 0w30 or 5w30. Too many people have used heavier oils in these than the recommended 5w20 for years now and no issues.
Once you see that it isn’t going to effect your MDS you’ll probably feel a lot better about it.
I also agree with your reasoning considering the use you describe with your truck.
 
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2 cSt at 100C is a pretty big difference in engine protection headroom.
Probably, but most engines last long enough anyway - the added margin is immaterial in the grand scheme of things when other “issues” often send a vehicle to the boneyard.
 

ZeeOSix

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Probably, but most engines last long enough anyway - the added margin is immaterial in the grand scheme of things when other “issues” often send a vehicle to the boneyard.
Depends on how the engine is used. More protection headroom and added MOFT can't hurt anything.
 
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