Bad knock out of nowhere! Please help

[wjburken]

So My 09 Yukon just started knocking last week. I was hoping for lifters or something lesser but the more I'm reading, the less confidence I'm having. The knock is consistent with rpms and acceleration. Check Engine and Stabilitrak flash at 2500 rpms, then rough idles for about a minute or two. I've changed the oil and added Marvel Mystery. It's quieted the noise slightly, but I'm still concerned.

Does your Yukon have the 5.3 or 6.2?
How many miles on your vehicle?
Have you been able to read the DTC codes with a scanner?
What did your oil look like when you changed it?

If you can post a video so we can hear the knocking, that might help folks here help you.

 

[iAmKendrickRay]

Does your Yukon have the 5.3 or 6.2?
How many miles on your vehicle?
Have you been able to read the DTC codes with a scanner?
What did your oil look like when you changed it?

If you can post a video so we can hear the knocking, that might help folks here help you.

5.3l v8
130k
I don't remember the exact readings but there were several.
The oil was super dark, didn't notice any sludge or metal.

I also noticed oil leaking near #7, but when we pulled the plug it was dry.

 

[wjburken]

5.3l v8
130k
I don't remember the exact readings but there were several.
The oil was super dark, didn't notice any sludge or metal.

I also noticed oil leaking near #7, but when we pulled the plug it was dry.

I would not rule out a lifter, or lifters, being collapsed. I believe your vehicle has AFM. Getting the codes would be helpful.

When you say oil is leaking near #7, what do you mean?

 

[iAmKendrickRay]

I would not rule out a lifter, or lifters, being collapsed. I believe your vehicle has AFM. Getting the codes would be helpful.

When you say oil is leaking near #7, what do you mean?

I'll post the codes tomorrow when I can run them again.
After I changed the oil and whipped away the residue, I started her up and I noticed leakage just below where #7 is but could not pin point exactly where it was coming from.

 

[wjburken]

I'll post the codes tomorrow when I can run them again.
After I changed the oil and whipped away the residue, I started her up and I noticed leakage just below where #7 is but could not pin point exactly where it was coming from.

Sounds good.

I noticed that it looks like you have a conversation on this topic going on two different threads. Might be good to keep both threads updated with your codes when you get them.

 

[iAmKendrickRay]

Sounds good.

I noticed that it looks like you have a conversation on this topic going on two different threads. Might be good to keep both threads updated with your codes when you get them.

I will... going to try and upload the video now.

 

[iAmKendrickRay]

Here's the video of the knocking with revs

 

[kbuskill]

Here's the video of the knocking with revs

Sounds too slow to be a rod knocking to me... sounds like half speed, so top end (cam, lifters, etc.)... IMO

 

[donjetman]

Sounds like its in the valve train to me too. Lifter, valve spring, rocker arm, push rod/

Not good

Don't drive it

Pull one valve cover at a time and look for the problem

 

[iAmKendrickRay]

Sounds like its in the valve train to me too. Lifter, valve spring, rocker arm, push rod/

Not good

Don't drive it

Pull one valve cover at a time and look for the problem

Unfortunately, we don't have a choice but to drive it. We're limping it when we do. Gratefully we don't have to go far.