I was just wondering if the Hemi engine can run on 87 octane or do you need to run the 89 octane as per the manual? In addition, does using 87 octane void the warranty? Thank You

 

Sure it can run on 87...anything will run on 87...

Long term effects is what I'd be worried with... ever been in a car when the engine pings? That's due to using the wrong octane fuel, the fuel will pre-detonate and cause carbon build up on the tops of your pistons and on your valves. Some people put in 87 and it runs fine....it's more of a long term effect. IMHO, I put in what's recommended by the dodge...it says 89 for a reason. That's when the fuel will burn off properly using an 89 octane fuel. I run 93 as well but thats when I am running a 93octane tune on my truck.

I don't think they can tell if you run 87 octane to void your warranty. My father is a service manager at BMW and says in the early e90's that they can detect when someone's car has been neglected to use the recommended 93octane or a cheaper brand gasoline over a period of time.. (thats a pure performance engine now).

Here goes another thread war....I can see it starting

 

All of the new vehicles "CAN" run 87 octane fuel, but it's not recommended and used repeatedly or long term will eventually result in engine damage. It should not spark-knock, as the ECU (computer) should detect it and detune the ignition accordingly but with commensurate sacrifice in both performance and MPG.

The engine is designed and engineered to use 89 octane fuel. If your real concern is the cost differential, then my personal opinion is perhaps you really ought not have bought the truck. People think I'm an arrogant ******* when I say this and I'm sorry if I offend you, but it's the truth: If you can't afford the fuel, how do you manage to afford the truck?

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While I do agree with the humour in all the MPG threads I see on full size truck forums, in this case, he didn't complain about cost or MPG. Simply asked if it is safe.

I do run 89 octane in my RAM, because I looked in the manual. However, the HEMI and Pentastar both recommend 89 octane, meaning every 300, Charger, Duranago, Grand Cherokee and RAM, should be running 89. but I will assure you that the vast majority will go their entire lives on 87 as most owner will never give it a second thought, or look in manual to read otherwise.

So it really is tough to say if it is safe or not. How many of these everyday people are having engine issues that can be concluded to be caused by the wrong octane? Likely not many.

That being said, I will still continue to use 89 as the price difference is minimal, and I feel better about doing it.

 

3rd Gen guys who have busted the skirting off their pistons and caused bent valves and cylinder damage ALL HAVE USED 87oct. I would highly reccomend NOT using it and sticking with 89 or better. Not a single engine failure from piston damage have been reported with the use of higher reccomended octane!

Sure a dealer can void warranty when they see busted skirting and signs of major predetonation! Overtime, predetonation carves gulleys into the top of the piston, almost like a hole punch has hit the piston surface hundreds of times. It's very easy to tell when someone uses cheap gas.

 

Mine has run almost 60,000 miles on 87 octane.

The manual says this:

The 5.7L engine is designed to meet all
emissions regulations and provide satisfactory
fuel economy and performance when
using high quality unleaded gasoline having
an octane range of 87 to 89. The manufacturer
recommends the use of 89 octane

for optimum performance.

 

agree w/ dirty dog 100%! Dirty Dog do you see quite a bit of 3rd gens coming in w/ that issue?

This is why I always fill up w/ quality gasoline and not jack and harry's gas stand. I'll pay the 5cents more a gallon for Shell, Chevron, or Mobil...

 

I wouldnt say alot, but all that have reported any issues were using 87oct.
I would guess around 15 members have reported this issue over the past 3.5yrs.

the problem is that Chrylser used the design of a nascar style piston for improved scavengine..etc, which places the rings very close to the top of the piston sleeve. This causes weakness and the erratic explosions of detonation fracture and break this thin edge off. Once this edge breaks off, it gets pushed out the exhaust valve and bend the valve. The remaining get tossed around inside the cylinder.
I have only heard 1 or 2 complaints about the bottom end being a culprit in hemi engine failures. most have been the piston issue.

 

Actually that's Lum 'N Abner's Corner Grocery, Bait & Boats Rented. Some of 'em are in the phone bidness too nowadays.

I too am a firm believer in using top grade (major brands) fuel. While I prefer to use Chevron (will drive out of my way to buy it) I'll also use Shell, Exxon & Mobil. If I'm driving out in the back woods and running low on fuel I might be forced to get some off-brand swill, but in that case I'll try to purchase only enough to get me back to civilization.

Contrary to folklore, the use of any octane higher than recommended by the manufacturer is foolish and a waste of money. By the same token, consistent use of lower than recommended octane is unwise. If it's truly "OK" to use 87, then why did the manufacturer recommend 89?

Interpreted another way, if the manufacturer says to use only 5W20 motor oil, do you think it would be "OK" to use single viscosity 30W non-detergent when the temperature outside is 5 below zero?

Do you change your oil filter too at every oil change? Why? Do you know that 50 years ago (I'm old enough to remember) it was standard practice to only change the filter at every other oil change?

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The manual is very clear, 97 will be fine.

Fuel Selection (5.7L Engine) 87 Octane Acceptable - 89 Octane Recommended