Rod Knock? Lifter Tick? Flex-plate noise?

[biigSam]

1st post and somewhat new owner of a 2002 GMC Yukon 2WD 130k fairly low confirmed with carfax. So it's legit.

Did an oil change and basic tune-up(plugs and wires) when I first got it and after a 600-mile road trip from dropping my nephew off at college, the engine started to tick/knock. My first thought was "****! It's knocking already"

Initially, I thought it was the rod bearing knock. Changed that.. no cigars
- Then I replaced the flexplate because, after some research, folks were having that issue as well.. no cigars
- Replaced the oil pump and timing set because after diagnosing there was too much slack.. no cigars
- CEL came on for knock sensors, 1 was flooded with water. Changed both with new wires and we're still in the same state.

In its current state, I've put about 5-6k miles on it.. with the tick lol. There's no loss in power. With the music on, I can barely hear it from the cabin. Definitely audible to everyone.

The oil(only 5w30 mobil1) looks normal between the 3 oil changes I have done. Now.. when I pulled the pan off to service the rod bearings and oil pump, there was a SHIT TON of sludge. I'm talking about prebaked brownie sludge! smfh I cleaned it out and it looks new again. This just tells me the previous owner did shit for maintenance.

After closer diagnosing with a long 3 ft screwdriver, the tick is the loudest from the #1 cylinder. I plan on pulling the valve cover and checking the rockers. I hope it's not a collapsed lifter or a mushroomed/shortened push rod. I really don't want to pull the heads off. Hoping it's something that just needs an adjustment.

I'll record a video of a cold start for you guys, when I get on my break.. lol I'm at work typing this out at the moment.

These are the lifters I'm looking at purchasing if it is.. or should I go with LS7 OEM lifters as I've read in other posts?

 

[Jeff Groves]

A bad push rod you shouldn't have to pull the heads. Lifters yes.
Then there is always the wrist pin knock.
Kind of rare but based on the lack of maintenance you describe? Not unusual.

 

[swathdiver]

These are the lifters I'm looking at purchasing if it is.. or should I go with LS7 OEM lifters as I've read in other posts?
View attachment 224055

I would always go with OE parts unless you know who made them for the OE, like Melling for the oil pumps and the lifters and some cams and such.

Welcome aboard btw!

 

[biigSam]

Video of tick from under hood and inside the cabin.

 

[Jeff Groves]

Sounds like a weak lifter.
Worst case would be a worn lobe on the cam.

 

[Tonyrodz]

Have you checked your codes again? I see your cel is still lit. Knock sensors still?

 

[iamdub]

Sounds like lifter tick, but pretty severe. I'd pull the heads ASAP. If the bottom end was sludged, then everything else will be, too. A lifter(s) could've been starved and collapsed and is stuck. I got a full set of GM LS7 lifters and retainers (trays) on eBay for $122. The Engine Tech ones you posted and other aftermarket ones MAY be ok. But, for anything internal, I'd go for the legit stuff for the peace of mind.

 

[biigSam]

Have you checked your codes again? I see your cel is still lit. Knock sensors still?

Funny you commented, I was just going through your build thread lol. But it's the flex fuel sensor. This thing lit up like a Christmas tree when I plugged the ABS module back in.. old owner unplugged it... smh

 

[biigSam]

Sounds like lifter tick, but pretty severe. I'd pull the heads ASAP. If the bottom end was sludged, then everything else will be, too. A lifter(s) could've been starved and collapsed and is stuck. I got a full set of GM LS7 lifters and retainers (trays) on eBay for $122. The Engine Tech ones you posted and other aftermarket ones MAY be ok. But, for anything internal, I'd go for the legit stuff for the peace of mind.

This is my first pushrod engine. Is it pretty easy to spot a bad lifter? I plan on pulling the VC off this weekend to check the rockers.

 

[Doubeleive]

sticky lifter, my 03 did it for 2-3 years then after a oil change one day it stopped it's done it once since then over the last couple years, although mine would do it generally at start up, then it would go away unless it sat and idled for a couple minutes. you might get lucky if you did some kind of engine cleanout, the problem is pretty typical for these engines never seems to be detrimental just mostly annoying.