Rattle under load sounds like rattle can or metallic clicking sound

[HelixRam12]

2021 Ram 1500 4x4, 50K KM

This noise has been bugging me for some time now. The dealer replaced both manifolds (which was not the issue). My bumper-to-bumper warranty has ended.

The sound only happens under 2-4K RPM acceleration; you hear a rattle sound. The sound is almost like a rattle can. It’s hard to describe. The sound does not occur in neutral or park when revving the engine. Even if you have it in drive, hold the brake, and give gas, you don’t get the sound.

The dealer and I have checked for heat shields and loose exhaust, but nothing seems loose. I have taken a mallet to the catalytic converters to see if something is loose, and they seem solid.

They replaced the manifolds, lower control arms and upper arms but could not find this issue. Or just chose to ignore it after.

Surely I cannot be the only that has this sound.

 

[Ram4Lou]

Pre-ignition (detonation), caused by using low octane fuel. Especially in hotter climates. Make sure you’re using 89 or higher. Or, the fueling station you’re using has bad gas.

 

[HSKR R/T]

Pre-ignition (detonation), caused by using low octane fuel. Especially in hotter climates. Make sure you’re using 89 or higher. Or, the fueling station you’re using has bad gas.

This ^^^

 

[silver billet]

Pre-ignition (detonation), caused by using low octane fuel. Especially in hotter climates. Make sure you’re using 89 or higher. Or, the fueling station you’re using has bad gas.

Unfortunately that only clears it up so much. Some get lucky but my truck pings on 91 as well. Not noticeable in day to day driving but towing it still shows up too much.

Probably needs a tune as well to dial down the timing a little. I just haven't gotten around to it.

 

[DEG]

I would try running a tank or two of 91 octane and see if the rattle goes away or subsides. If it does, it is detonation knock and you need to have your knock sensor system checked out. Even running low octane fuel you should not hear detonation knock as your knock sensors should have sensed it and retarded the timing to eliminate it.

It's also possible to have a bad ignition component like spark plugs that contribute to detonation knock. You should be able to run 87 octane fuel without every hearing detonation knock. I have in all 4 Hemi's I've owned.

 

[silver billet]

I would try running a tank or two of 91 octane and see if the rattle goes away or subsides. If it does, it is detonation knock and you need to have your knock sensor system checked out. Even running low octane fuel you should not hear detonation knock as your knock sensors should have sensed it and retarded the timing to eliminate it.

It's also possible to have a bad ignition component like spark plugs that contribute to detonation knock. You should be able to run 87 octane fuel without every hearing detonation knock. I have in all 4 Hemi's I've owned.

Nope, both my and my brother's truck have done it from day one. Some people just don't hear it, or they live in a different region (better gas, different elevation, humidity, temperatures etc, they all effect ping).

If you read the manual it will say that some amount of ping is normal.

 

[HelixRam12]

Thanks everyone, I will try a fill up with 94 octane and see what happens.

 

[silver billet]

Thanks everyone, I will try a fill up with 94 octane and see what happens.

Please post back with your results, I'm quite curious. I haven't tried > 91.

 

[HelixRam12]

Filled the tank with 91 and after a quarter tank the sound did go away. That’s crazy that it won’t accept 87.

 

[DEG]

Filled the tank with 91 and after a quarter tank the sound did go away. That’s crazy that it won’t accept 87.

It should accept 87 octane without hearing detonation knock. I've run 87 in 4 different hemi Rams in every imaginable condition and never heard detonation knock in any of them.

 

[Scram1500]

Manual refers to it as slight knocking and states that it's normal

 

[DEG]

A rattle that sounds like a rattle can is not light knocking and is not normal with 87.

 

[silver billet]

Filled the tank with 91 and after a quarter tank the sound did go away. That’s crazy that it won’t accept 87.

It does "accept it". Your engine won't blow, but obviously it's happier on 91. Some guys here are just in denial. I run 91 full time, it is what is.

 

[SD Rebel]

As Silver Billet stated, so many variables could be effecting how your engine is reacting to the fuel in your area. I also run 91 octane, but that's because Costco doesn't offer 89 and their 91 is cheaper than other stations 87.

I think I ran 87 in the past with no issues (however I'm not very sound sensitive, I could easily miss my engine pinging). But since 91 meets or exceeds the recommendation of 89, I go with that instead, especially for Top Tier rated Costco prices.

 

[HSKR R/T]

Manual refers to it as slight knocking and states that it's normalView attachment 185618

Knocking is not "normal". Any detonation is harmful to the engine.

 

[SD Rebel]

Knocking is not "normal". Any detonation is harmful to the engine.

The manual states "light knocking" is not a concern, but heavy knocking is. So both right?

 

[HSKR R/T]

The manual states "light knocking" is not a concern, but heavy knocking is. So both right?

Any audible knocking is bad for the engine. By the time it gets bad enough to hear, damage is already being done in the combustion chsmber

 

[Scram1500]

The manual states "light knocking" is not a concern, but heavy knocking is. So both right?

How long is it before light knocking becomes heavy knocking?

Knocking is not "normal". Any detonation is harmful to the engine.

Yeah not normal, can't believe they print that nonsense

 

[SD Rebel]

How long is it before light knocking becomes heavy knocking?

Yeah not normal, can't believe they print that nonsense

I have no ear for pinging, no idea what it even sounds like. That's why I use 91 (or 89 if as cheap as Costco 91)

 

[DEG]

I have no ear for pinging, no idea what it even sounds like. That's why I use 91 (or 89 if as cheap as Costco 91)

You don't need to have an ear for it. When it sounds like a rattle can you will hear it unless completely deaf. Most people don't know what it sounds like because it is an abnormal condition, even if running 87 octane in a hemi. Back when points and plugs were only good for about 30,000 miles, detonation knock was a sure sign you needed a tune up.