Kk engine knock

[LibertyKK]

So after lots of searching I have to ask about this engine knock.

Just purchased at 2010 limited 157k miles. At idle 500rpm engine is smooth and good. 600-800rpm definite knock seems to be coming from lower end of drivers side (engine noise is hard for me, but used a wooden dowel) after 1000rpm it clears up engine seems to run good, and makes good power. I have changed the plugs with NGK copper, new wires should be here tomorrow (don’t think that’s the issue but they are due). After purchase I had a shop change oil with mobile 1 full synthetic. (Not in a spot I could change myself, so couldn’t see if oil had glitter in it!)Wasn’t making noise at purchase so maybe the synthetic oil made it more noticeable? Pulled plug wire from individual coils with no change in knock. We are in central TX and will be driving to MN in a few weeks hopefully she holds together.

 

[LibertyKK]

Had some time this afternoon, and pulled the serpentine belt (needed to change it anyway) and to my surprise no knock. New belt back on and started knocking again. Rookie mistake I guess.. I thought the knock sounded too deep to be an accessory, but guess I was wrong. Thinking it must be harmonic Balancer, or water pump (water pump is brand new). Although I’m not convinced sounds like someone is banging on my oil pan with a small leather mallet

 

[sleazy rider]

Spin the belt tensioners by hand while the belt’s off and feel for wobble/drag/stiffness.

 

[lfhoward]

Had some time this afternoon, and pulled the serpentine belt (needed to change it anyway) and to my surprise no knock. New belt back on and started knocking again. Rookie mistake I guess.. I thought the knock sounded too deep to be an accessory, but guess I was wrong. Thinking it must be harmonic Balancer, or water pump (water pump is brand new). Although I’m not convinced sounds like someone is banging on my oil pan with a small leather mallet

Best news yet! Not terminal rod knock!!!

On mine with about 205K, I have replaced the water pump multiple times, the belt tensioner twice, and the AC compressor by now. The AC compressor bearings were pretty sketchy and it was leaking refrigerant. I guess all that’s left now that is an original accessory is the alternator and power steering pump with their original bearings & pulleys.

 

[LibertyKK]

Spin the belt tensioners by hand while the belt’s off and feel for wobble/drag/stiffness.

Everything spins free and seems tight. Tiny bit of play on the power steering pulley.

 

[LibertyKK]

Changed belt tensioners this morning for peace of mind. No change I’m stumped might have to see if a shop can figure out

 

[ltd02]

You mentioned harmonic balancer. Did you watch it while running? I had one starting to fail on an 11 avenger and you could see it wobble. They can be tough to see and look OK. The rubber fails but they don't actually get loose at first.

 

[LibertyKK]

You mentioned harmonic balancer. Did you watch it while running? I had one starting to fail on an 11 avenger and you could see it wobble. They can be tough to see and look OK. The rubber fails but they don't actually get loose at first.

I looked pretty close. If it is wobbling it is very little, if at all. Checked for any kind of looseness by hand and seemed solid. It does have surface rust on it as expected. Crawled under Jeep with serpentine belt on again yeterday, and would swear the knock is coming from the flex plate/TC (one of the first things I checked), but makes no since that it quits with accessory belt removed. I’m sure it’s something simple, but I can’t seem to track it down. I will be out of town 5th-8th and have an appointment to get it into a shop on the 13th. I’m sure I’ll spend time looking again today but I’m running out of ideas

 

[LibertyKK]

3 days at the shop, and I am no further than when I started. Shop says they have no idea what the knock could be. Left them scratching their heads. Although it makes me feel better about myself, it doesn’t help track this down.

 

[Aeroscott]

If yours has a 6 speed manual transmission, the dual mass flywheel may be making noise, mine squeaked sort of but when I pulled the trasmission, I found a loose dual mass flywheel, and a worn out clutch at 150k miles, maybe if yours is a manual , this could be the cause, if it's an automatic, I would pulle the cover and look for loose torque converter bolts. I see now after reading the last couple posts, you do have an automatic, and you've already checked the TC to flex plate bolts, good luck.

 

[joes2010]

Best news yet! Not terminal rod knock!!!

On mine with about 205K, I have replaced the water pump multiple times, the belt tensioner twice, and the AC compressor by now. The AC compressor bearings were pretty sketchy and it was leaking refrigerant. I guess all that’s left now that is an original accessory is the alternator and power steering pump with their original bearings & pulleys.

2010 Liberty i just put a used engine in and soon as its a little warm have the exact same issue as you do pulled belt and noise gone only in gear backing up or going forward once you get moving its gone ever figure it out Joe [email protected] or my cell 586-489-6278 any help would be greatly appreciated!

 

[joes2010]

Best news yet! Not terminal rod knock!!!

On mine with about 205K, I have replaced the water pump multiple times, the belt tensioner twice, and the AC compressor by now. The AC compressor bearings were pretty sketchy and it was leaking refrigerant. I guess all that’s left now that is an original accessory is the alternator and power steering pump with their original bearings & pulleys.

hope you figured yours out thanks let me know!

 

[lfhoward]

Is this a true knock (like a misfire or detonation) or a tapping sound? Is it all the time or just when you start it up? Pretty much all the 3.7’s have a tapping sound for the first few minutes until they warm up.

 

[LenMan]

my step son has a 2013 Chrysler 200 and it had a knock. Pulled the belt off no knock. Turned out to be the alternator because the alternator incorporates a clutch mechanism and it was failing. Got another alternator and that fixed the problem. FYI

 

[LibertyKK]

hope you figured yours out thanks let me know!

Sorry I haven’t been very active. Has been a long summer. 20k miles and I still have the knock. Assuming it is the alternator but Im not 100% have some yearly maintenance to catch up on, so I might just swap it out and see.

 

[veritasaequita]

Anybody ever figure out the final cause of these issues. Same problem as stated

 

[MsRandiCook]

Could it be lifter noise? I have lifter noise when it's sitting. Goes away after it warms up.

 

[LibertyKK]

Still haven’t figured it out. Definitely not the lifters. Changed the Alternator a couple weeks ago and knock is still there. Had the Jeep in the shop for a misfire code yesterday, and had them see if they could narrow down the knock. They didn’t have any luck. Although it bothers me I quit caring 10k miles ago. Jeep is performing great otherwise.

(just to refresh the knock only happen with a warm engine can only hear it around 700 to 1500 rpm. It either goes away at higher Rpm or gets drowned out by engine noise. At idle there is no knock)

 

[David H. Brotemarkle CPA]

I had the same knock and found it was the ac compressor. Changed that and no more knock. Engine runs fine. That was about a year ago and all is still good. Heater core is current problem.