Reposted for the afternoon Oppos

For a while I’ve been getting a ticking from my engine. Actually as far as I can remember it’s had at least some, but 5.3's are known for it so I never worried about it... Now it seems like it’s getting louder.

It’s coming from the #7 cylinder area as far as I can tell. Anyway, I finally decided to pay a little attention to it and counted the frequency. Best I can make out, it’s ticking 48 times per 10 seconds at idle. So in a minute, that’s almost exactly half the engine RPM. Definitely valvetrain. (ETA: Just thinking about it, technically it could be a noisy injector too, that would also show up every 2 RPM) Fun.

Anyway, I’ve come up with a bunch of things I think it could be and a course of action. Input please?

- Noisy injector. Try a tank or two with some kind of cleaner. If it works, great, if it comes back, I’m not terribly bothered—there haven’t been any performance issues or idiot lights. At least I’d know what it was and what I’d have to replace when it DOES cause problems.

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- Clogged/sticky lifter. Oil additive? Open to suggestions.

- Completely fried lifter. If this is it, it’s been going long enough that it’s probably taken the cam with it too. Personally, apart from the uncertainty of not knowing for sure what the problem was I’d just let this one go for a while. It hasn’t caused any issues, performance is good, it’s just noisy right now. When it’s truly finished, I wanted a new cam anyway.

- Poor oil pressure, lifter at the back suffering. I dunno what to do here because GM in all their infinite wisdom decided to omit an oil pressure gauge. I guess I’ll get it checked when I do the oil change. I doubt it’s the issue because I’d think #8 would be ticking too, but it’s an option.

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- Related to above, maybe the pickup tube has eaten (or started to) it’s o-ring? It’s a known issue, at least with the earlier engines. Maybe the schmoo from it got caught up in one of the #7 lifters?

- Oil pump? 114,000km I highly doubt it.

- Cold emphasizing the 5.3 tick and I’m overreacting.

Help please. I’ll try and get a recording and update this.

EDIT: Recordings:

First cold recording, inside wheel well and under truck

Hot, same location

Hot, underhood, some moving around but mostly around #7

Hot, underhood, clockwise circuit of engine starting at #7

Hot underhood

Hot underhood, #7 area

Hot, outside, revving

Cold

Cold, 3-4 minutes at idle, wheel well

That’s a lot of recordings of the same thing, but I figured I took them so I might as well include them.

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Not sure what to think now. Compared to some lifter tick videos I looked up it actually seems quite mild, if it’s even the same thing. Gave it a light Italian tuneup on the way home last night, seemed to help a bit, but it’s still there. It’s a nagging noise in the background... the one that make it sound vaguely similar to a diesel.