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Discussion Starter #1 (Edited)
Was at the Dodge dealer today looking at a leftover, new 2017 R/T.

When I started it, it cranked a little slow then caught then made a "Clunk" noise coming from the engine,
It did it every time I started it.
The noise reminded me of an old car that would run on for a couple seconds after shut off, but not that long.
Almost sounds like a crankshaft noise??
Anyone hear of this??
 

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If you had recorded the sound it would be easier to try and figure out.
 

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make me wonder if its like the sound older cars did (hot soak startup) where there'd be detonation in a cylinder during startup. Used to notice this more on 70s/80s models.
 

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Discussion Starter #4
make me wonder if its like the sound older cars did (hot soak startup) where there'd be detonation in a cylinder during startup. Used to notice this more on 70s/80s models.
That's exactly how it sounded Hal just not as long...
 

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Discussion Starter #6

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If it is at a dealer, check several others with the same engine. If they all do it then it is normal, something engaging and/or disengaging. What? I cannot tell from here. Exactly where the sound comes from is as important as what it sounds like to tell what is making it.
 

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Its brand new on the lot, and the manual says 87 is fine....its the auto.
87 is fine for the SXTs and acceptable for 5.7 auto (89 recommended). The manual must run 91. Only other way I could imagine detonation occurring on start up is if the PCM is programmed with too much timing advance. What is more plausible is the fuel quality is poor. This is assuming what you are hearing is detonation.
 

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If it is at a dealer, check several others with the same engine. If they all do it then it is normal, something engaging and/or disengaging. What? I cannot tell from here. Exactly where the sound comes from is as important as what it sounds like to tell what is making it.
I bought a new 2019 SXT two weeks ago. About 50% of the time, it makes the clunk when starting. While it was in the shop getting stripes installed, I drove another brand new 2019 SXT as a loaner and it made the same clunk about 50% of the time when starting. It might be normal but that doesn't make it acceptable in my book. Something must be loose or not firing right. I'm gonna check with the dealer.
 

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Hmm, have never heard a "clunk" when starting my 2018 GT (same 3.6L engine)... Would be really helpful if you could record the sound for us.
 

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Motor mount?

Sent from my SM-N960U using Tapatalk
 

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I bought a new 2019 SXT two weeks ago. About 50% of the time, it makes the clunk when starting. While it was in the shop getting stripes installed, I drove another brand new 2019 SXT as a loaner and it made the same clunk about 50% of the time when starting. It might be normal but that doesn't make it acceptable in my book. Something must be loose or not firing right. I'm gonna check with the dealer.
Have you ever found out what the problem is?.... I have the same thing with a 19 GT
 

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Have you ever found out what the problem is?.... I have the same thing with a 19 GT
Hi cujo221, We certainly understand why this may be concerning. We kindly recommend having your dealer inspect this concern for you as they are in the best position to assist. If you do work with your dealer, we would be more than happy to provide you with additional support.
Rob
DodgeCares
 

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I have been to Pinebelt Dodge in Lakewood NJ.....they were not able to duplicate the condition. Condition occurs 10% of the time when starting.
 

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Wonder if it could be related to the OCV?

"Each phaser position is adjusted using regulated oil pressure through the Oil Control Valve (OCV) (3). To begin phaser movement, a voltage signal is applied to the Variable Valve Timing (VVT) solenoid (1) to extend or retract the solenoid pintle (4). The pintle pushes against an internal spool valve (2) within the OCV moving the valve forward and backward to direct oil flow.
At engine startup, system oil pressure overcomes spring pressure and unlocks the phaser lock-pin (1) in preparation for phasing. The phasers remain in this position until a PCM signal is given to pulse-width modulate the VVT solenoid. At engine shutdown, as oil pressure is reduced, both Phasers return to their lock-pin position."

On my challenger (can happen on my JGC if engine is hot, on a hot day and I quickly restart the motor after shutdown) I have had condiitons where I stall the motor (has an M6) and when I go to quickly restart the engine it will knock/ping once just at start-up even though I run shell 93 exclusively. Now on a V6 minimum recommended octane is 87 so it's plausible that an instance of knock at start-up of a hot engine may occur even thought the PCM is factory tuned to avoid this. I have logged start-ups on both vehicles and the knock sensors do seem to pick-up either mechanical noise or actual knock. Just spit balling here.
 

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Noise is coming from behind the driver under the chassis. Either exhaust or drive train can't determine which. But occurs as soon as the engine starts and only 1 out of 10 times.
 

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So your clunk is different from the OPs? I think what you are hearing is the driver's side exhaust pipe making contact with the spare tire well.
 

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I think it must be something with all the 3.6 engines my Grand Cherokee does it too. I thought it went away but it’s back from time to time.
 

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In Cujo's case I really suspect it could be the pipe hitting the spare tire relief in the trunk as he claims it sounds like it is behind the driver. When I first installed my aftermarket exhaust I had very little clearance in that spot which would cause the pipe to contact usually at start-up as that is when the greatest movement of the exhaust would occur. Now if it sound like what the OP stated, I really wonder if it is knock at initial start-up that is being heard? If so, it most likely would only happen at hot start and not during cold start.
 
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