Syntec name has been discontinued. Edge is the top of the line Castrol now. Ask them for the European stuff. May have it stuck somewhere other than the oil racks if it's not out front. Use part numbers. Works better than descriptions for some of the counter monkeys.

5W40 may be easier to find.

2010 would run 15/40 and 5w/40 if you live in an ice box….. like Nord Dakota
Honestly if your 2010 is stock the oils getting so polluted with the regen strategy that synthetic is a waste. Regen is why they have the service reminder. At a calculated interval of 2-3% oil dilution the “oil change required” message comes up. They “said” that they’d tested up to 10% dilution without any ill findings. The 08-12 6.7 (pre DEF) they recommended at oil change to have the level at the “S” in safe on the stick. That would give room for growth due to fuel dilution….. I never thought I’d see the day where it was “normal” for the oil level to rise during a service interval. 08-12 was a must to delete imho……

Sorry - I meant Edge.

Okay, I'm confused. I thought that with a Cummins, during the filter regeneration raw diesel fuel was injected ahead of the catalytic converter to raise the exhaust temp to 'burn' the filter out. If this is the case, how does this contribute to oil dilution?

Fuel gets past the rings….. the oil level will rise in that era.

You are aware engines have changed drastically in 50 yrs...right? Clearances, OHC, DOHC, VVT, DOD,AFM,mechanical high pressure fuel pumps, variable displacement oil pumps...the list goes on...those are all part of modern lube systems. You can mess with manufacture suggestions all you want.....I would not!

You did note synthetic is NOT required in this application, 2018 Jeep GC, 3.6? IIRC, full synthetic is only required for SRT's at this time. I think the biggest move in synthetics these days is in the 0W category. As I recall from the "old days" extreme temperature breakdown resistance was the primary benefit of full synthetics. I AM using it (5W-20) in our newer cars because the dealer quit offering semi synthetic, full synthetic is NOT required AT LEAST ACCORDING to Chrysler. MS-6395 IS required.

With that out of the way, there is a case to be made for full synthetic in the 3.6 because of failing rocker arms. Is it an oiling failure, design issue, quality issue? dunno. Early Pentastars required 5W-30, in 2013 they changed it to 5W-20. Only the first guess do we have any control over, but there's LOT's of failed 3.6 rocker arms that have ONLY been fed a diet of full synthetics, so crapshoot.

FWIW, our Hemi lifters are noisy no matter what oil they're fed.

For the cost of nitrogen, I'll go through the drill of adding air every fall.

Neither dealer I talked to could tell me when Chrysler started "requiring" the 3.6 to use nothing but 0w20. My 300 is a 2016 & the Dodge dealer does all the oil changes & uses semi-syn 5w20. So far, no rocker arm issues, even though I get clatter which is quite audible when the engine is cold - takes about 10 minutes of driving before it subsides. I've had two dealers look for this & they come back with "no rocker arm issues" each time. Personally, looking at repair videos & listening to what the Chrysler techs are saying, I don't see how these rocker assemblies can remain trouble-free in under 100,000 miles. Same thing with the driveshaft center support bearings on the 300's & Chargers. THEY ARE ALL GOING TO FAIL PREMATURELY! If you are driving a late model Charger or 300 & you are starting to feel a driveline vibration at highway speeds, it's the center support bearing! It's a 2-grand repair if you are out of warranty.

Rant off.

My wifes 12t&c van with3.6 calls for 5w-30 for oil 298kand no problems with anything in the engine,Sons 2016 chrysler 300 with a 3.6 198k calls for 5w-20no problems both were bought with less than 30k on them oil &filter changed every 4000miles.

Something else to consider is that the 0-20 oil may be recommended as that’s how they tested the engine and “maybe” they were able to see a slight mpg improvement. EPA loves when corporate can show them that.