Long Time L99 Owners...Chime In, Plz

[acutron42]

I had the same issue as Eddymel1998 described. I was hesitant to do my header install with this noise but went ahead anyway. The 1st manifold bolt head on #2 snapped off & I honestly don't know what was holding it on. Sure enough the gasket was blown out. The noise was gone after the install.

[myold88]

Originally Posted by Aqua Blue RS/SS

I’ve beat on both of mine, red line pulls daily when driving it and never had any problems. The problem is real but sometimes I think it’s slightly exaggerated on the net.

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I agree. Exaggerated by guys that don't have it.

[Aqua Blue RS/SS]

Honestly it depends on the parts being used. Cheap lifters and cheap cam core=big problems. If you can get documentation on the exact parts they are going to run that will be a better judge if it’s a good deal or not.

[1JEWLDSSRS]

Originally Posted by Aqua Blue RS/SS

Honestly it depends on the parts being used. Cheap lifters and cheap cam core=big problems. If you can get documentation on the exact parts they are going to run that will be a better judge if it’s a good deal or not.

^^^ This for certain! If subpar parts are used, yeah you're going to have problems down the road. Make sure all the parts are top tier stuff. And does that price reflect the new Melling oil pump, chain, damper, converter you're going to need for the cam size, and a trans cooler to keep the trans temps down. I made sure when we did my build to have the best, and I checked out everything they installed before the work was done, so I knew what I had paid for. And mine expense ended up being 6500 dollars, before covid.. lol.

[Moto-Mojo]

Makes total sense. I trust the source. And the decades of relationships that lead me to the source. Thanks, men. (no offense to the ladies still hanging here)

[Moto-Mojo]

Originally Posted by Aqua Blue RS/SS

Let it sit for a week or two and then pay attention to how it sounds for the first second or two on startup as the lifters re prime. That’s the sound you don’t want to hear under normal running. If it’s not making those sounds and oil pressure is good than you’re likely fine.

I didn't acknowledge your post. It's definitely at start up. It might last a minute or two, slowly getting quieter. It's probably fine but I'm gonna defuse the time bomb!

[acutron42]

Hey Moto, Here is a video from Ryan Stevens @ GPI going over the whole afm delete check list. I am not trying to sell you on GPI, just give you some info that covers the subject as a whole.

[Moto-Mojo]

Originally Posted by acutron42

Hey Moto, Here is a video from Ryan Stevens @ GPI going over the whole afm delete check list. I am not trying to sell you on GPI, just give you some info that covers the subject as a whole.

Thank you for this!

[Modernmusclecar]

Most guys saying it's a lifter likely don't have an l99 . I find some have louder valvetrain noise then others....but a bad lifter will be a completely different sound.

[joshnmn]

If it’s mostly at startup and quiets down after a couple of minutes I would lean more toward an exhaust leak. Gasses leak by the seal until the manifold/header get hot enough to expand.

[70T/A400]

I had AFM lifters fail on my 2015 GMC Sierra at 75,000 miles

You will know when it happens, your dash will light up like a UFO and the driveability is like riding a covered wagon.

Changing the oil frequently and a range disabler does not get rid of the problem. The hydraulic system does not fail. The spring inside the lifter does.

The one way to get rid of it is to install a new camshaft and new lifters and tray. Do not change the lifters only as the hardness on the camshaft has been worn.

Sounds like you do not have the issue.

If you want to see how widespread it is, go down and visit your Chevrolet or GMC dealership. They will have several trucks in there.

[edog]

I did the LS3 conversion in 2014. I have always had the sewing machine effect noise. I just switched to Johnson Lifters after a full motor rebuild. No more sewing machine effect noise and sounds great.