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I’ve been using the wrong gas.

rcadams27

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Bought a 2019 1500 5.7 off the lot brand new 2.5 years ago. When I purchased the vehicle I asked the guy if I needed to use premium which I assumed and he assured me that these new trucks run fine on “regular”. Not reading the owners manual like I wish I would have I have been putting in “regular” since I bought the truck. Kicker, I live in Colorado and our regular is 85 octane. I started noticing a metal clinking sound that reminded me of two washers hitting each other when accelerating and hanging around 2500 RPMs. After having it looked at multiple times with nobody being able to find anything wrong I realized I’ve been using the wrong gas after searching for hours in the internet. I am going to switch to our premium which is 91 octane. Wondering if I caused any damage to the engine in 30k miles? Also is there an additive or something I can throw in a tank of gas that may help reverse any damage I’ve done? Other than the noise the truck seems to run great and I haven’t noticed any issues with power or anything but this sound has been driving me nuts. Thanks for any advice.
 

Fatherof3

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Welcome to the forum . Generally speaking the Hemi is ok on 87 octane but is recommended 89 octane . I've run 87 , 89 and 91 with no noticeable difference in performance . I don't think you would have to worry about any damage unless it's been pinging and/or knocking a lot . I think once you switch to the higher octane you'll be fine .
 

mikeru82

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There's no reason to go to 91. I'm not sure what's available in your area, but you'd be fine with 87 or 89 octane. From what I've read, 85 at altitude is like 87 at sea level. Does the noise go away with higher octane fuel? If so I wouldn't worry about it. If not, 🤷‍♂️
 

UnloosedChewtoy

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Run a few tanks of premium 91 through there. If the ping noise goes away, then thats your proof your engine wants something better than 85. It takes a few tanks to get all the "old" gas out of there, so don't get frustrated if you have no results after the first tank of 91.

Every engine can be different. I'm doing the same thing with mine right now. Mine seems to hate ethanol more than most, which is in most fuels up in my area, even Costco. I used to run 91 with 10% ethanol usually (Costco), and she will ever so slightly ping under moderate throttle if I hit the right RPMs/speed, usually merging onto the highway. I started running 91 non-ethanol (only 1 tank so far) from a different station, and after two or three tanks, we'll see if there is a difference. I know my MPG is up by about 0.5-1 (in city), which I expected, as ethanol hurts your MPG as well.
 
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SD Rebel

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87 is acceptable, 89 recommended, but 91 is also fine to use. I would use 89 if Costco offered it, but they only have 87 or 91. If you use 91 Costco, it meets FCA's octane recommendation, its Top Tier and cheaper than most other gas stations 89 or even 87, which is why I use it.
 
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GKIII

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The only reason 85 octane gas exists is because carbureted vehicles tolerated it fairly well at altitude, so it was allowed for sale since it's cheaper. It's not really meant for use in modern engines. RAM calls for 89, with 87 being acceptable. You should *not* be using 85. With a naturally aspirated engine the risk isn't quite as high, but at higher RPMs or load you *will* notice spark knock like you have here. Hell, I've noticed it using 87 before.

Ford goes as far as to specifically call out 85 octane fuels as warranty voiding, RAM doesn't go that far in their explicit warranty language but they do say using fluids (which, can be argued fuel counts as one) that don't meet minimum recommendations will result in warranty denial. Obviously, they'd need to determine if that fluid doesn't meet that minimum spec but since you live in Colorado I wouldn't be surprised if the first thing they sample is the fuel in your tank if you happened to come in with a trashed motor for warranty work.

*If* (which, admittedly is unlikely because modern engines can retard timing...up to a point) your motor has physical damage (scuffed cylinder bores, pitting on valves, damaged pistons/rings, etc) the damage is not reversible by simply using higher octane fuel and will require an engine teardown.

BLUF: Your engine is probably fine, just stop using gas that it wasn't designed for (MINIMUM 87) if you want it to stay that way.
 
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djevox

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If you’ve been letting this happen for a while under moderate to high loads, then you probably have some minor pitting on the pistons and valves from detonation; however, it’s not the end of the world. Just move the octane up to the next higher rating and see if it resolves it.
 

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