Odd Engine Noise

[SelfmodJT]

That’s the most Jeep thing I’ve read all night!!

Its like having a hot girlfriend thats bi polar what you gonna do? Have fun, or get rid of her?

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[jmdwifi]

If your dealer says it's normal, just have it noted on the worksheet that they heard it detonate and told you it's normal so it's on record. Your warranty for the engine is 60k miles or 5yrs, just drive the shit out of it and keep using 87. If it's not normal, theres no way itll go 60k and stay intermittent. If it's a constant rattling for secs at a time and clearly audible they have to address it. If youre close to 60k and it's still intermittent then perhaps it's not doing anything to the engine. Either sell it or buy an extended warranty for peace of mind. You're gonna drive yourself crazy if you keep let it bothering you everytime you drive. It's not something you cant control so fuk it, turn up the radio.

I have not been to the dealer yet. I heard this noise slightly when turning a corner at low speed and slight acceleration. I had the doors off for the last 4 days and drove 6 or 7 hundred miles out of town and back. I notice it happens most times accelerating under load. It isn't extremely loud but it does sound like a diesel. I have put 89 in it and made no difference. I am pretty sure this thing will go past 60,000, I am already at 34,000. Guess I have 26,000 to decide. I am not going crazy, I just think it's bullshit to call an obvious not right engine fight inside my engine, normal.

 

[SelfmodJT]

I have not been to the dealer yet. I heard this noise slightly when turning a corner at low speed and slight acceleration. I had the doors off for the last 4 days and drove 6 or 7 hundred miles out of town and back. I notice it happens most times accelerating under load. It isn't extremely loud but it does sound like a diesel. I have put 89 in it and made no difference. I am pretty sure this thing will go past 60,000, I am already at 34,000. Guess I have 26,000 to decide. I am not going crazy, I just think it's bullshit to call an obvious not right engine fight inside my engine, normal.

Sounds like a diesel? It should sound like a rattling or bacon sizzling sound. If its bad like a can of marbles, never heard that it sounds like a diesel. Maybe you have a different issue.

 

[ShadowsPapa]

Sounds like a diesel? It should sound like a rattling or bacon sizzling sound. If its bad like a can of marbles, never heard that it sounds like a diesel. Maybe you have a different issue.

Possibly.

The thing is he's describing what thousands of vehicles do.......... and have done for years. But without hearing it and using experience to differentiate between sounds, anything is a guess.

The thing about these Jeeps is that they are not well insulated (from sounds), they catch a ton of road noise and they are unique in that you can have them totally opened up and hear things no one may otherwise hear - so suddenly what would be not so unusual in a Ram truck or a Grand Cherokee with thick solid walls and insulation becomes more apparent.

But no one likes to believe possibilities, even when expressed by experience.

Since the sound is easily replicated by mildly lugging the engine (which is what's happening here) then it can be heard by a mechanic........... and as long as they have heard it and stated it's ok, make sure they DOCUMENT this, get a copy showing they explained it as normal or not a concern.

Here's from one tech article I have -


The combination of vehicle and engine can result in specific requirements
for octane that depend on the fuel. If the octane is distributed differently
throughout the boiling range of a fuel, then engines can knock on one brand
of 87 (RON+MON)/2, but not on another brand. This "octane distribution" is
especially important when sudden changes in load occur, such as high load,
full throttle, acceleration.

Some fuel specifications include delta RONs, to ensure octane distribution
throughout the fuel boiling range was consistent. Octane distribution was
seldom a problem with the alkyl lead compounds, as the tetra methyl lead
and tetra ethyl lead octane volatility profiles were well characterized, but
it can be a major problem for the new, reformulated, low aromatic gasolines,
as MTBE boils at 55C, whereas ethanol boils at 78C. Drivers have discovered
that an 87 (RON+MON)/2 from one brand has to be substituted with an 89
(RON+MON)/2 of another, and that is because of the combination of their
driving style, engine design, vehicle mass, fuel octane distribution, fuel
volatility, and the octane-enhancers used.

In short, fuels with ETHANOL may help............. and not all 87 octane fuels are necessarily the same. And driving habits, etc. can enter into it. I tend to shove the throttle harder to force downshifts and get out of that lugging range - I hate trying to accelerate with the tach sitting at 1500-1800 RPM so I push harder and force a downshift (if it was my car, I'd downshift the thing and take the RPM up higher - detonation takes time so higher RPM is less likely to detonate - it's one reason drag racers with very high RPM engines can get by with what they do)

 

[arneb04]

Here’s some quick perspective on this, because I occasionally hear some odd noises when accelerating. The JT is small, not insulated like a full size truck, and is somewhat of an oddity in that the exhaust outlets on the drivers side. Most single outlet exhausts on are the passenger side unless dual. Why the JT is driver I don’t know, but that will absolutely play a factor in the type of noises you hear against sound barriers or at the drive through.

 

[shokker70]

Same sound here. Think I posted in 1 of the other threads about it. 2 different dealerships had zero clue. No code, so no problem is the general answer. This is not an issue of the transmission lagging, or RPM dropping. I've had this exact thing doing 30 and holding steady, or 70 cruising down the tollway. Doesn't seem to matter. Accelerating do not seem to be a cause. Although I don't believe I have ever heard it at idle.

 

[SelfmodJT]

Same sound here. Think I posted in 1 of the other threads about it. 2 different dealerships had zero clue. No code, so no problem is the general answer. This is not an issue of the transmission lagging, or RPM dropping. I've had this exact thing doing 30 and holding steady, or 70 cruising down the tollway. Doesn't seem to matter. Accelerating do not seem to be a cause. Although I don't believe I have ever heard it at idle.

You heard it going 70? Something else going on there, i cant hear anything at 70 because of all the tire and road noise. You must have super hearing. What noise are we talking about anyways? Might be in the wrong thread lol.

 

[shokker70]

You heard it going 70? Something else going on there, i cant hear anything at 70 because of all the tire and road noise. You must have super hearing. What noise are we talking about anyways? Might be in the wrong thread lol.

Yeah, my ears are that attuned to it. I was probably listening for it. Was a few months ago. But very similar sound as the recording the OP posted. And always short and sweet. That part never changes. Barely lasts a second.

 

[jmdwifi]

Sounds like a diesel? It should sound like a rattling or bacon sizzling sound. If its bad like a can of marbles, never heard that it sounds like a diesel. Maybe you have a different issue.

I guess I mean similar to a diesel, more like marbles I guess. it is the exact sound in the video earlier. I just hear it more often now.

 

[shokker70]

I guess I mean similar to a diesel, more like marbles I guess. it is the exact sound in the video earlier. I just hear it more often now.

That was my initial description as well. Not a diesel sound, but diesel'ing'. That's not what it is, but a decent descriptor.

 

[SelfmodJT]

Just out of curiosity, where do you guys hear the noise coming from? The engine, middle of undercarraige or near the back where the exhaust is?

 

[jmdwifi]

Just out of curiosity, where do you guys hear the noise coming from? The engine, middle of undercarraige or near the back where the exhaust is?

Engine

 

[SelfmodJT]

Engine

Hmmm I wonder why I hear mine coming from mid to rear of the undercarraige. Only reason I know it's not from something loose is because it makes no noise before reaching operating temperature and it only makes the noise on inclines during acceleration. Reguardless I dont care about it because the dealer wont do anything until the cel light comes on or it's a constant rattle that lasts more than a sec. I just had it recorded on my service reciept for future reference.

 

[JTsGarage]

Hmmm I wonder why I hear mine coming from mid to rear of the undercarraige. Only reason I know it's not from something loose is because it makes no noise before reaching operating temperature and it only makes the noise on inclines during acceleration. Reguardless I dont care about it because the dealer wont do anything until the cel light comes on or it's a constant rattle that lasts more than a sec. I just had it recorded on my service reciept for future reference.

I have the same issue on my Overland, 3.6, automatic. Very similar to what you describe. Definitely comes from underneath, usually only happens on inclines during acceleration. Over the holiday weekend the sound was noticeable driving over a high-rise bridge at a beach here in NC. Otherwise, it rarely happens. I've never been to the dealer about it. I figure if there was a real issue or solution, I'd learn about it on this forum. I've had too many bad experiences at dealers who "fix" at least two unrelated items before fixing what I actually came in for.

 

[SelfmodJT]

I have the same issue on my Overland, 3.6, automatic. Very similar to what you describe. Definitely comes from underneath, usually only happens on inclines during acceleration. Over the holiday weekend the sound was noticeable driving over a high-rise bridge at a beach here in NC. Otherwise, it rarely happens. I've never been to the dealer about it. I figure if there was a real issue or solution, I'd learn about it on this forum. I've had too many bad experiences at dealers who "fix" at least two unrelated items before fixing what I actually came in for.

I think more people have this noise issue and dont know about it. If you only drive with the window up with the ac on, it will barely be audible. Especially if you have the radio on too.

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