5.3 Engine Tick well above Idle

[Red88GTA]

Folks-

We have a 2008 Suburban. 50K miles. Oil changed twice a year. Dexos oil with Purolator or ACDelco filter.

2 months ago, we started hearing a loud ticking noise when accelerating ABOVE 1800 RPM. The noise is coming from the #1 cylinder so this may be a bad AFM lifter. Verified it was not an exhaust leak - took heat shield off and looked carefully and it doesn't have that bright sound of an exhaust leak.

Oil pressure is normal - above 40 above idle. No SES light. Changed oil to Mobile 1 Synth, and it helped but you can still hear the noise often. Seems like its fine if on a trip when engine gets thoroughly warmed up. Even while parked, over ~1800 RPM it starts ticking. Wife says when its ticking, the idle is a little rough and truck feels a little sluggish (knock sensors detecting noise?.?).

Question, can a bad lifter only make noise over ~1800 RPM and be completely quiet below that speed? Is that a "weak" (AFM) lifter? If not, is this some kind of carbon issue? ANY thoughts appreciated. All I can see is $$$$

 

[1_8TTony]

Multiple ticks or does it sound like one.

 

[Red88GTA]

Just the #1 cylinder - definitely in that left front corner. If this is lifter, I doubt removing valve cover will tell me much since it is quiet at low RPM's. Can't figure out why, if its a lifter, doesn't tick below 1800 rpm.

 

[MichaelSE]

It might be worth a try running some Seafoam through the brake booster vacuum hose. If it were a carbon issue, that might dissolve the carbon. Do you have a mechanic's stethoscope? If so, have someone rev to 2000 in park and see if you can further pinpoint the noise.

 

[jrobie79]

I had issues with ticking on my escalade 6.2....sounded a lot like lifters. I ran a few bottles of gumout regane through it at fuel fill-ups, no real noticeable change in the sound, maybe my injectors sounded quieter.

Then I bought kroil "kreen" and put it in my oil. Drove it 1000 miles then changed it out. This was only 2,000 miles after I had recently changed it. Noticably quieter, and the oil was definitely way darker than it should have been at 3k, especially for a synthetic.

I'm gonna do a 5k oil change interval this time, 4k into it, I'm gonna use the kreen again and drive it for 1000 more miles then change it again.

so far I'm a believer.

http://www.kanolabs.com/engCle.html (no affiliation)

 

[Red88GTA]

I've heard about this stuff before.. Hard to believe this engine would be dirty.. 48K miles on it with basically 3K oil changes, but I may try this.. I just changed the oil as mentioned. Ticking is quieter, but definitely still there. We are lost on what to do.. Completely quiet below 1800.

We've been looking at midsize SUV's but they are boring compared to our loaded out Suburban. Drove a new Suburban and it felt gutless unless you stomped on it.. Engine was ticking also - probably injector, not sure. And it was $$$$!

Thanks