Thread: Knocking Sound from Engine bay.

Well, I broke an axle last night so I finished up my axle install then took the car out for a test drive. Ran great, pulled hard and was nice and smooth. No shakes. Get the car home and shut it off in the driveway. Clean up my tools and the garage and start the car to pull it in.. and its knocking.. Sounds like a flex plate to me, but I may be wrong. I replaced the flexplate last year with a low mile L67 one from a friend. What do you guys think? I got a video.

****s broke. - YouTube

Yep, looked at it and it looks fine, but I can't see all of it. Could be cracked like my old one was around the center.

I'll drive it till it breaks. I'm not worried about it. I have friends who have driven 6k miles on a broken flex plate, just annoying. I'm pretty sure its the flexplate so I'll replace it if it is but I just wanted other opinions.

sounded like it went away once you hit a certain rpm.

I'd check TQ bolts too, maybe one came loose and tq is moving around.

But it dont sound bottom end to me.

Here's my video from last year when my first one broke...

Bye Bye L67... - YouTube

So I'm pretty sure it's the same thing. Last time it happened I pulled the motor and threw my cam in, what can I do this time? lol

I'd guess it's the flexplate..I also replaced mine twice...

But...it also does sound like a chipped piston slapping against the head..(what happened to me, hopefully not to you)

Sounds very similar, and when I'd rev it, it would stop due to the getting smushed into the head and sticking there, just barely clearing.

Meziere plates are expensive.

That's why I'm not going with a Meziere.

Meziere plates don't break.

Well... the sound isn't there when the engine is cold. Which leads me to believe I spun a bearing.

spun bearings will knock hot or cold on everyone I've seen.

Well I'm not quite sure at this point. My buddy Shawn is coming over tomorrow to get another opinion. But the sound changes when I put it in drive and reverse, so that makes me think flexplate.. lets hope that's all it is.

Sounds like the flex plate.. When mine goes, I'm going meziere.. Fix it once and be done with it

Meziere is also $400... I'm throwing in a GT converter and flywheel.

Originally Posted by BoostenGTP

Meziere is also $400... I'm throwing in a GT converter and flywheel.

$400 is worth it IMO to have to only fix it once.

It's the flex plate. Found the crack and also got "expert" opinions from Shawn who has broken 10 flexes lol. So it'll be changed this weekend.