2012 Yukon 6.2 Engine Noise

[j91z28d1]

probably more things but definitely shake the rockers and look for a loose one and is it loose because the bearings in the middle are sloppy or missing. that's actually pretty common on ls engines. check that all the valves are the same height. that can be a sign of a seat dropped in the head. inspect the valve springs for broken ones.

you'll have to turn the engine over by hand so each cyl has both valves closed and feel for slop. if you find one the next step is find out why it has slop.

 

[iamdub]

What should I look for once I get the valve cover off?

I agree that it sounds lifter- or valvetrain-ish. Look under the valve cover(s), starting with the driver side if it's louder there. Check all the springs very closely. Check the rockers for any up and down slack. You might have to manually turn the engine to check the rockers that are pushing on the valves. If it's a partially collapsed lifter or bent push rod, it might not be enough lost slack to be apparent unless the rocker is unloaded. It sounds minor, but it won't stay "minor".

 

[12XLYukon]

I agree that it sounds lifter- or valvetrain-ish. Look under the valve cover(s), starting with the driver side if it's louder there. Check all the springs very closely. Check the rockers for any up and down slack. You might have to manually turn the engine to check the rockers that are pushing on the valves. If it's a partially collapsed lifter or bent push rod, it might not be enough lost slack to be apparent unless the rocker is unloaded. It sounds minor, but it won't stay "minor".

Took the valve cover off tonight. None of the rockers feel loose at all. Turned the engine over manually and couldn’t find any slack or movement anywhere in the rockers that way. Turned the engine over with the key to verify all the rockers are moving. I’m open to any other ideas.

 

[donjetman]

do the same to the other side/bank of the engine.

 

[Bourban Man]

Hi all, I just recently bought a 2012 Yukon XL Denali with the 6.2. It has developed a noise that I can’t identify. It has 214k on the miles.
Noise is coming from driver side and can be heard from under the hood and in the wheel well.
Louder on cold start but still present after driving.
No codes and runs smooth
Oil pressure when idling is 20 at operating temp and 42 when cold started.
Checked the exhaust manifold bolts and all are there except one on passenger side.

I had the same noise in 2011 Yukon XL 2500 with a 6.0. I changed the oil and drove it 500 miles then changed the oil again and drove another 1500 miles before changing again and lifter noise went away. No special additives just good clean oil letting the detergents do their job. 280,000 miles and just returned from Florida towing a 24' boat 2200 miles and my bad ass Yukon still going strong and no lifter noise. I now change the oil (full synthetic) every 3k. This will be my 2nd Yukon to drive over 300k. I change the oil like crazy and drive it like I love it.

 

[12XLYukon]

do the same to the other side/bank of the engine.

Took off the passenger side valve cover and did the same thing. Everything looks okay nothings loose and everything is moving as it should. I’m really not sure what to look for from here.

 

[iamdub]

Took off the passenger side valve cover and did the same thing. Everything looks okay nothings loose and everything is moving as it should. I’m really not sure what to look for from here.

Did you happen to take any pics of how it looked under there? Curious of amount and/or type of buildup, if any. It could still be a collapsed lifter. Maybe not totally, but "weak". It might be solid enough that you can't feel anything or compress hard enough with your fingers but be too squishy when being thrown around by the cam lobe.

What oil do you use? I'd hate for us to send you down a rabbit hole. But, even considering how cam mics can color sounds, it really does sound mechanical. I'd say to invest the $8 in a mechanic's stethoscope and try to narrow it down to a particular area or cylinder.

 

[Dustin Jackson]

Took the valve cover off tonight. None of the rockers feel loose at all. Turned the engine over manually and couldn’t find any slack or movement anywhere in the rockers that way. Turned the engine over with the key to verify all the rockers are moving. I’m open to any other ideas.

@12XLYukon This test will only tell you if there is a problem, it doesn't tell you if everything is correct. For example, a lifter turned in the tray will still operate the rockers to the naked eye.

 

[Dustin Jackson]

@12XLYukon Keep digging, if there is a problem and you haven't found it yet you haven't dug deep enough.

 

[12XLYukon]

Did you happen to take any pics of how it looked under there? Curious of amount and/or type of buildup, if any. It could still be a collapsed lifter. Maybe not totally, but "weak". It might be solid enough that you can't feel anything or compress hard enough with your fingers but be too squishy when being thrown around by the cam lobe.

What oil do you use? I'd hate for us to send you down a rabbit hole. But, even considering how cam mics can color sounds, it really does sound mechanical. I'd say to invest the $8 in a mechanic's stethoscope and try to narrow it down to a particular area or cylinder.

I use 5w30 Mobil One synthetic with an ACDelco filter. Here are some pictures of the driver side. I didn’t stop to take pictures of the passenger but everything looked the same as far as color and buildup.