Rattle from engine when accelerating (sounds like keys)

[Hootbro]

Most of these are saying the engine is making noise when hot. Has anyone noticed a diesel like rattle when its freezing cold and the engine is accelerating at low RPM? Sounds like the engine is lugging. Goes away when engine warms up.

What temps below freezing we talking about? Anything in the 10's and below, all my Pentastar engine vehicle I have owned to include my Gladiators will be somewhat noisy under load for a couple of minutes. I just contribute that to oil flow and seems normal to me considering.

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[MagnusWolf]

What temps below freezing we talking about? Anything in the 10's and below, all my Pentastar engine vehicle I have owned to include my Gladiators will be somewhat noisy under load for a couple of minutes. I just contribute that to oil flow and seems normal to me considering.

I thought it was normal too but wanted other people's input, it has been getting down to 19 degrees F lately, and yes that is what I am talking about, the engine seems louder when under load at low RPMs when cold, usually in first and second gear it sounds faintly like a diesel clatter when accelerating slowly or going up a hill, To me it sounds like the engine is lugging. At idle it is quiet and smooth. usually the noise is completely gone after the coolant temp reaches 175.

 

[Hootbro]

I thought it was normal too but wanted other people's input, it has been getting down to 19 degrees F lately, and yes that is what I am talking about, the engine seems louder when under load at low RPMs when cold, usually in first and second gear it sounds faintly like a diesel clatter when accelerating slowly or going up a hill, To me it sounds like the engine is lugging. At idle it is quiet and smooth. usually the noise is completely gone after the coolant temp reaches 175.

Yeah, you got something different going on. When I have the lugging on a cold morning with similar temps, it is gone within a 1/4 mile driving down the road. I am not one to warm up a engine on a cold morning start. Usually I just jump in, start and the time it take to connect my phone, I am driving. No where near having to reach a 175 degree temp before the engine lugging goes away for me.

I assume you are not using some straight weight oil or something stupid like 15W-40 or 20W-50?

 

[LiftedrubiconJT]

Did you ever figure out what was causing your flutter like sound? Mine has a flutter like sound.

Yup I got a flutter-like noise in the 3.6L before any service at all was done to it. I can only hear it at low speeds when accelerating or coming to a stop.

It’s gotten quieter since the first day I heard it about 2 weeks ago. Truck drives fine and I’ve only ever heard it in the morning.

Edit: To clarify, I don’t know if the noise is actually “in” the engine, I just stated the engine type for reference. The noise doesn’t sound metal on metal at all.

 

[DailyMoparGuy]

Did you ever figure out what was causing your flutter like sound? Mine has a flutter like sound.

I sure didn’t. I haven’t heard it in almost a year either. I can’t even make a guess to what the noise was unfortunately. I’m at 19k miles now and had my 3rd oil change at 18k miles.

No performance issues BUT the truck idles hard sometimes. It’s not consistent though and the service guy couldn’t replicate it. I first noticed the rough idle around 1k or 2k miles. It hasn’t worsened or improved. Again, no performance issues though.

How many miles on yours? Any idle issues?

 

[LiftedrubiconJT]

I sure didn’t. I haven’t heard it in almost a year either. I can’t even make a guess to what the noise was unfortunately. I’m at 19k miles now and had my 3rd oil change at 18k miles.

No performance issues BUT the truck idles hard sometimes. It’s not consistent though and the service guy couldn’t replicate it. I first noticed the rough idle around 1k or 2k miles. It hasn’t worsened or improved. Again, no performance issues though.

How many miles on yours? Any idle issues?

Just hit 37,000. No idle issues. My only issue is this slight flutter like sound at around 3k rpm’s. Sounds like a fan noise

 

[jmdwifi]

Mine sounds like a ping on low speed acceleration. No point in taking it in. I still have an emergency brake sticking problem and my aux battery always charging. The dealers and jeep don’t really care. They will send you a video of them not fixing your truck. So that’s something.

 

[Jeepin' John]

Same, unfortunately. I can't figure it out. I feel like if it's knock, the engine would have grenaded by now.

Same thing here. No idea what it is, and just rolling with it. Nothing has changed it, not fuel octane, not oil viscosity, not oil catch can, not teraflex crank ventilation system (all of which developed leaks, but that's another story).

No rough idle or engine performance problems, just get the rattle at low speed and light throttle input periodically. I'd assume if it was something to worry about, the engine would have already let go. But it may or may not even be engine related. Who knows.

I've been running 0w-20, the OEM PCV line and 87 octane due to no change in how the engine runs. Runs great and gets great mileage. Just makes that weird rattle every once in a while

 

[ShadowsPapa]

I've been running 0w-20, the OEM PCV line and 87 octane due to no change in how the engine runs. Runs great and gets great mileage. Just makes that weird rattle every once in a while

I'm not there to hear it personally, and I'm not there to try to force the sound and diagnose - see when it does happen and when it doesn't happen, so take this as if a doctor told you exactly what virus you had based only on symptoms like a head cold...........
It sounds like you do have a slight ping from detonation - the sort "the book" says is "normal" and "nothing to worry about".
And I'd agree if it is as you describe and certain assumptions can be made.

I still find it extremely interesting that I have never heard that out of my own truck - no matter the conditions, even when I try to duplicate it so I might have an idea of what others are hearing............
But these do operate on the edge with the compression ratio and other factors. The open deck design should allow for great cooling of the upper cylinder and chamber area and they can control combustion pressures to some extent with valve timing and valve opening/lift but it looks like lift is likely based only on RPM and nothing else. Dave could confirm or deny that part.

 

[DAVECS1]

https://www.sae.org/news/2015/08/2016-pentastar-v6-adds-new-vvt-cooled-egr

 

[DAVECS1]

Also interesting reading

 

[ShadowsPapa]

Also interesting reading

I'd love to spend a day training under your guidance.

 

[Scrubb84]

I'm not there to hear it personally, and I'm not there to try to force the sound and diagnose - see when it does happen and when it doesn't happen, so take this as if a doctor told you exactly what virus you had based only on symptoms like a head cold...........
It sounds like you do have a slight ping from detonation - the sort "the book" says is "normal" and "nothing to worry about".
And I'd agree if it is as you describe and certain assumptions can be made.

I still find it extremely interesting that I have never heard that out of my own truck - no matter the conditions, even when I try to duplicate it so I might have an idea of what others are hearing............
But these do operate on the edge with the compression ratio and other factors. The open deck design should allow for great cooling of the upper cylinder and chamber area and they can control combustion pressures to some extent with valve timing and valve opening/lift but it looks like lift is likely based only on RPM and nothing else. Dave could confirm or deny that part.

The fact that some have the rattle and some don’t makes me believe there is absolutely a problem.

 

[ShadowsPapa]

I would "expect" that with CEGR, the intake designed to introduce turbulence, and other fun stuff, the "rattle" should be very rare. It would take some serious monitoring of the various temperatures, such as with the CEGR, etc. to see if things are operating in tolerances, but on the edge of said tolerances.

 

[shokker70]

This was a big time issue on my Sport S. Would hear it multiple times a day. I've heard it a grand total of 2 times in 8k on my Mojave, but still heard it. I've decided to chalk it up to, "it just does that."

Nutz as it may seem, I may be trading my new one for a Texas Trail with an EcoDiesel (and Gobi since it's back). Kinda doubt I'll hear it anymore... I should start a thread!

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