Dan Poelstra

I'm afraid it's a lifter, but its so quiet at idle. I get a little lifter rattle at cold start up, for about 30 seconds ds or so...different sound to my ear... I haven't checked spark plugs...I'll do that.

https://youtube.com/shorts/bt20_L0XqUQ?feature=share I've posted this around looking for anyone who's seen this before. No luck... I recently picked up this truck. Had one owner most of its life with good consistent service records. 99 5.3l. Good oil pressure, no misfires codes, no codes at all for that matter. Runs perfect except for this tick. The tick Shows at about 1500 rpm, silent at idle. Doesn't really matter if engine is cold or warm, load or no load. Always there between 1500 and about 2200 RPM... I've tried Lucas oil stabilizer and Mystery oil...no effect. Recently drove it over 300 miles in a day, still no change. Appears to be crank speed, not cam speed, I think. I got a stethoscope and can only really hear it through the second valve cover bolt, even at idle when I can't hear it normally. Valve cover itself can't hear it, just on the one bolt. I've searched for exhaust leaks and can't find anything. Doesn't sound like lifters or even piston slap...just a different sound. I was thinking rocker arm or valve spring, but that would be cam speed...Doesn't make sense. Doesn't even sound like a rod knock... I'm hoping someone else has see this before before before i start removi g val e covers.

Think I found my exhaust leak. Had a drip of water after I moved the truck into the driveway.

Have you heard a lifter tick that shows only at mid range rpms? Every description I can find is pronounced ar idle...I'm trying to rule things in or out...the quiet smooth idle is a telling sign to me, but don't have enough experience with the 5.3l to say for sure.

Hard to hear but...

Hi, new here hoping for some.expertise. New to me 99 Sierra 5.3l has a mid RPM tick. Not loud but it's there. Quiet idle...only shows between 1800 and 2500 RPM. I've heard the lifter and rod knocks and they are very pronounced ar idle. My idle is perfectly quiet. Good oil pressure, no codes. One broken manifold bolt and I installed a bracket but made no difference. Doesn't seem to matter if it's cold or warm... I suspect an exhaust leak, but need some expert opinions on this. Any thought? Thanks! Dan