Noise coming from motor on 2012 KK w/90,000mi.

[Jump]

I'm hearing some interesting noises coming from the top and bottom-end of the motor under low load/initial startup, between 900-1,200 rpm. My guess is maybe rod bearings. Need someone to share their experience. Thank you!

https://photos.google.com/share/AF1...?key=TEN1RmstZ3FKRXlLYkE5VnJSaHpfWFQxVVFqZ0tB

 

[lfhoward]

I had a rod bearing go on mine at 86K. The noise sounded more like metallic clacking than what I hear in your video. It also got really loud when revving the engine under no/light load. Under load it was quiet. Does your noise get louder/quieter at higher rpms, or when under load?

Take the serpentine belt off and then start the engine (for a short time so it doesn’t overheat). This will eliminate all your accessories that may have a bad pulley or bearing and make rotational noise. See if the noise is still there.

Fingers crossed that it isn’t a rod bearing. If the noise goes away after it warms up it could be a bad lifter/rocker arm that is being starved for oil at the beginning when the engine is cold. Try changing to Mobil-1 synthetic and it will help dissolve the crud that may be obstructing oil passages in the lifters and quiet it down.

An oil analysis from https://www.blackstone-labs.com/
will be able to identify if you have bearings that are wearing out by the metals in your oil. You could send them a sample.

 

[David H. Brotemarkle CPA]

I had a similar noise when I bought a 2008 Liberry. I thought oh no! Turns out it was just the air conditioner pump. Mechanic could hardly believe it. Changed the compressor and all has been fine.
good luck.

 

[Jump]

I had a rod bearing go on mine at 86K. The noise sounded more like metallic clacking than what I hear in your video. It also got really loud when revving the engine under no/light load. Under load it was quiet. Does your noise get louder/quieter at higher rpms, or when under load?

Take the serpentine belt off and then start the engine (for a short time so it doesn’t overheat). This will eliminate all your accessories that may have a bad pulley or bearing and make rotational noise. See if the noise is still there.

Fingers crossed that it isn’t a rod bearing. If the noise goes away after it warms up it could be a bad lifter/rocker arm that is being starved for oil at the beginning when the engine is cold. Try changing to Mobil-1 synthetic and it will help dissolve the crud that may be obstructing oil passages in the lifters and quiet it down.

An oil analysis from https://www.blackstone-labs.com/
will be able to identify if you have bearings that are wearing out by the metals in your oil. You could send them a sample.

My noise only happens at low to no load. For example if I put it in gear and hold it with the brakes it will be more obvious, otherwise it only happens under 1K rpm and goes away at higher rpms. Could it just be a dead cylinder from a temperamental spark plug or coil? I'll go through the general rigmarole of checking that and accessories soon.

Also, just as a general question, would the ecu ever throw a code from a rod bearing if it's causing a misfire? Or would I just have to know from the noise?

Thank you for your reply!

 

[Jump]

I had a similar noise when I bought a 2008 Liberry. I thought oh no! Turns out it was just the air conditioner pump. Mechanic could hardly believe it. Changed the compressor and all has been fine.
good luck.

I'll make sure to look into it, thank you!

 

[Jump]

UPDATE: It was something stupid. One of the spark plugs was not properly seated from a prior tune up and caused both noises and a miss at low rpm. Thank you guys for your input, I'll keep your advice in mind for future endeavors.