4age making a tapping noise

[Moebius]

Car - AE71

motor / part in question - bigport 4age

problem - Making a tapping noise

occurs/started when (if applicable)- Happened when I started it up for the first time in a few weeks. Was running fine previously.

I don't really know how to describe the noise other than a tapping sound. It doesn't sound to me like an injector ticking noise or an exhaust leak. I've tried listening to various parts of the engine with a rubber hose up against my ear and I can't pinpoint where it's coming from. The noise goes away when I rev the engine, but comes back immediately once it drops back to idle. I've only run it for a few minutes but it didn't seem to go away after warming up.

I've taken the rocker covers off and there is nothing that jumps out at me as being wrong. I checked all the valve clearances and they are all within spec, except one of the exhaust ones which is 0.03mm extra. The oil was changed only a few hundred kms ago, and still looks fresh both on the dipstick and in the head.

This is the best video I managed to get where you can hear the noise - https://youtu.be/xT7P22dCTiQ

[Matt]

Usually exhaust or intake gasket leak causes a similar noise

[Moebius]

Hmm, okay. I think I've only had leaks further back so I don't know what it sounds like from one of the manifolds. Is there any way to pinpoint where a gasket leak is?

[maxhag]

look for black soot marks at joins/cracks/gaskets

[timbo]

What oil/weight are you running? Sounds mechanical to me, but do as stated and check for soot around the exhaust manifold. Was there much oil under the cam covers?

[sirsprinter]

Sticky lifter? One that failed to reach hydraulic pressure after sitting for a bit? Im curious too because mine is making a similar noise, but scarier.. yet to have it looked at. But good luck with your issue mate. Hopefully something simple

[Moebius]

There was a small amount of soot on the gasket under one of the exhaust ports, but it didn't seem major. I turned the crank by hand and all the lifters appeared to be okay from what I could tell.

I've got an oil pressure gauge and a stethoscope now so I'll see if I can narrow it down.

[Hen may possibly be a nut]

4AGEs don't have hydraulic lifters, they use buckets and shims.

[sirsprinter]

4AGEs don't have hydraulic lifters, they use buckets and shims.

Cheers hen; ive already been corrected on that - i should have edited the original post.

*hen i thought you were replying to my thread where i posted a similar issue and incorrectly mentioned hydraulic lifters too lol

[Moebius]

Well after connecting the oil pressure gauge it was reading 71 psi while cold idling at about 2k rpm. Seemed a bit high, but after it had been running for a few minutes while I was searching for the source of the noise with the stethoscope, the pressure dropped down to about 40 or 50 and the noise started quietening down. So I dropped the oil and put some 10w-30 oil in and now the noise seems to have gone completely. Seems a bit odd to me, as I had run it for probably about ten minutes before that and the noise was still there, so I don't really know what changed.

[davew7]

Seems a bit odd to me, as I had run it for probably about ten minutes before that and the noise was still there, so I don't really know what changed.
I would guess that you had some slug, gasket, or RTV, break loose and block an oil passage. Just running the engine [high oil pressure] allowed the material blocking the passage to pass thru the system. Hopefully the filter will catch it and prevent and more problems. Might want to do an oil and filter change. Davew7