Engine Knocking

[AleksandreK]

Engine knock on load, at low RMP.
Idles fine, no ticking at middle and high rmp.
(As i heard its rocker arm noise and thats common problem of pentastar engine)
Any suggestion?

JLUR 3.6
37s
Using 87 octane

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[rubileon]

RTFM

 

[DaltonGang]

Engine knock on load, at low RMP.
Idles fine, no

It looks like you are driving it like a Manual. Put it in drive mode, and let the tranny do what it is supposed to do, downshift. If it still continues, take it to the dealer.

 

[Johnbuz]

There are several discussions on this topic in the 3.6 subforum. It's a common problem. The consensus is that once the engine gets up to operating temp, the tune is too lean and you get knocking under load conditions at low RPM. Until there is a new tune, the mitigations are to run higher octane and try to keep the RPM'S over 2k. Cooler weather seems to help also.

 

[rubileon]

There are several discussions on this topic in the 3.6 subforum. It's a common problem. The consensus is that once the engine gets up to operating temp, the tune is too lean and you get knocking under load conditions at low RPM. Until there is a new tune, the mitigations are to run higher octane and try to keep the RPM'S over 2k. Cooler weather seems to help also.

If the owner's manual says it's fine and if you still call it a "problem", return it.

And how realistic is it exactly to keep rpms over 2K? Forget it. Use good fuel like anyone should and just drive the damn thing!

 

[Johnbuz]

If the owner's manual says it's fine and if you still call it a "problem", return it.

And how realistic is it exactly to keep rpms over 2K? Forget it. Use good fuel like anyone should and just drive the damn thing!

The last vehicle I drove that knocked was a 1987 Chrysler Lebaron. A modern engine should never knock, thats the purpose of the sensors. So no matter what a manual says, its a problem.
I can often keep the RPMs above 2k by delaying when I shift into the next higher gear when accelerating. With the automatic transmission it would be harder to avoid.

 

[HeavyUser]

Have you tried a tank of 93?

 

[traxtion]

Oof this is the worst example I have heard... mine does the same and I have taken it through every FCA back channel only to be told "operating as designed." Assuming you have re-geared for the 37s?

The good news is that you can eliminate the knock with 91/93, or an octane additive. I ran 87 in the winter unless I was wheeling, and then ran 89.

Would recommend taking it in regardless to get the noise documented, my gut tells me they will fix the PCM tune at some point when engines start to die prematurely. I imagine this will be after 50,000 miles, so you'll want proof this was a problem to begin with.

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