Identifying 2013 6.2 Tick (attached video)

[thefrey]

2013 Yukon Denali 6.2 199k. AFM not deleted. Intermittent tick. 15psi hot idle and maybe 22psi cruising at 1800psi. Fresh full synthetic 5w30 oil changed about 800 miles ago.

Yukon is new to me, I bought it at about 197k. Last owner said that they replaced the lifters at about 190k but who knows.

The tick is very intermittent. Can be heard sometimes when the engine is fully hot, but sometimes there is no noise. Tick sounds more prominent while near the wheel well(s). It seems to almost always happen when the engine is cold but is very much 50/50 when hot. I did a "warm" start today after truck had been sitting for an hour or two and didn't hear a tick on startup

What are the chances that it's an o-ring issue? I've heard that a bad oil pickup o-ring can sometimes cause a clatter. Not sure though. I'm also not sure if it sounds more like an exhaust leak or a mildly sticky lifter.

 

[swathdiver]

I can't really tell, sounds like a noisy injector to me. Get a long extension or mechanic's stethoscope. Stick one end in your ear and touch the other end to parts you suspect the noise is coming from. If you have long hair, get it out of the way of the accessories spinning 'round and 'round lest you scalp yourself!

Oil pressure is lower than normal. Probably too low for AFM to turn on.

 

[thefrey]

I can't really tell, sounds like a noisy injector to me. Get a long extension or mechanic's stethoscope. Stick one end in your ear and touch the other end to parts you suspect the noise is coming from. If you have long hair, get it out of the way of the accessories spinning 'round and 'round lest you scalp yourself!

Oil pressure is lower than normal. Probably too low for AFM to turn on.

Here's another video perspective from the passenger side wheel well

Yup, AFM won't activate when hot. It does when it's cold though with the higher PSIs. Not sure if the AFM not activating would affect any lifter tick

On another note, found 1 stud broke, a couple missing bolts, and a bolt halfway out on the manifold. So maybe that could be something as well

 

[donjetman]

@thefrey
Sounds like a valve train issue to me.
Could be:
loose/worn rocker arm
lifter preload incorrect
bent push rod
broken valve spring

 

[thefrey]

@thefrey
Sounds like a valve train issue to me.
Could be:
loose/worn rocker arm
lifter preload incorrect
bent push rod
broken valve spring

I haven’t had the privilege of getting this deep into an engine before lol. What’s the best way to diagnose something like this? Should I start by taking the valve cover off and observing from there?

Also is a collapsed lifter out of the question here? Not exactly sure if the noise could be a lifter issue

 

[j91z28d1]

Here's another video perspective from the passenger side wheel well

Yup, AFM won't activate when hot. It does when it's cold though with the higher PSIs. Not sure if the AFM not activating would affect any lifter tick

On another note, found 1 stud broke, a couple missing bolts, and a bolt halfway out on the manifold. So maybe that could be something as well

fix all the broke bolts first.

 

[swathdiver]

Here's another video perspective from the passenger side wheel well

Yup, AFM won't activate when hot. It does when it's cold though with the higher PSIs. Not sure if the AFM not activating would affect any lifter tick

On another note, found 1 stud broke, a couple missing bolts, and a bolt halfway out on the manifold. So maybe that could be something as well

Whether it's an exhaust leak from all the broken bolts or a broken valve spring, I don't think any of those has anything to do with low oil pressure.

I'm chasing low oil pressure and a related leak right now. Lose too much oil and the pressure drops. Another day of rain and then I can get after it hopefully.

 

[rdezs]

It does sound mechanical in nature to me . ... A stethoscope would confirm a mechanical noise under the valve cover or under the engine valley cover.

Assuming you clearly hear a mechanical sound in the engine, I'd pull off the passenger side valve cover and check the trunions, as well as rotating the engine over by hand and checking for a push rod that is extremely loose indicating a collapsed lifter. And definitely fix the broken or missing bolts in the manifold.

A 2 ft long stick works great as a stethoscope. Even a wood broom handle cut off. Grab one end with your fist and put it against your ear and the other end against different components. You'll be surprised what you can hear. Keep long hair and loose clothing away from the belts....

 

[rdezs]

.... And while that oil pressure is on the low side, it's still well above with GM says is okay. I don't think that's low enough to cause any lifter noise..... But it wouldn't hurt to confirm the oil pressure readings with the mechanical gauge.