05 Tahoe Z71 Valve Train Noise

[3joh]

05 Tahoe Z71 newer Long block with approximately 70K on it. Excessive valvetrain noise that just started today. I narrowed it down to the passenger side.

No engine misfire. No CEL. During hard acceleration prior to the noise today, I could occasionally get what sounded like valve float for a short bit.

Pulled the passenger valve cover, cranked motor and saw that all rockers were moving as they should. Normal side to side play was the only thing evident EXCEPT on cylinder #2. There was quite a bit of loose movement which would leave a gap above the pushrod end. I tried to compress the pushrod/lifter by hand and could not.

This motor has always been noisier than I am used to and I think this is the culprit. What do you think? lifters?

Oil is clean and has regular interval changes. Tahoe has been gone through from top to bottom and has 308k on the clock with original paint.

How do i attach videos?

 

[3joh]

 

[Matthew Jeschke]

Did you make sure the valves were on the heal of the cam when you tested for play in the rocker arms / pushrods?

Possibly piston slap?

I had bad lifter tick. Here's what I did to clean it up...

- remove valve covers
- pour ENTIRE can of sea foam onto rocker arms such that it goes down pushrod and into lifter
- reinstall valve covers.
- Let engine sit overnight.
- Idle engine for one hour (DO NOT DRIVE).

If the noise went away change your oil. Otherwise, DO NOT CHANGE OIL. You will proceed with extra strength procedure.

- Remove valve covers AGAIN
- Do same thing but this time with spray can OR two of Berryman B12 Chemtool. You want to make SURE you are absolutely SATURATING top of the lifters and getting the cleaner to sit in on the piston.
- Reinstall valve covers
- Let engine sit overnight again
- Drain the oil, leave filter.
- Put a few quarts of oil into the crankcase, enough for pickup to pressurize the system.
- Start engine and run it for a minute or so to flush out residual Berryman B12
- Drain oil, remove filter and put new.

Hopefully that fixes it. Otherwise, the lifter/lifters maybe trashed. Some people also try running a quart or so of ATF (has stronger detergents in it).

 

[rockola1971]

You may have a lifter hanging up. Drop a quart of ATF in the engine. Let it run at idle for 30 mins in driveway. DO NOT DRIVE IT. Oil change and if its a lifter hanging up she will STFU.

 

[strutaeng]

Yes, sounds just like my 06 suburban that had an intermittent lifter noise.

Wound up pulling the engine for a refresh. I took apart the lifters and one had sand-like particles inside.

Try the cleaning options first. Hopefully it will go away...