BAD knock...even when warm *VIDEO*
This is a discussion on BAD knock...even when warm *VIDEO* within the Internal Engine forums, part of the LSx Technical Help Section category; Just tonight I discovered a really bad knock that seems like it is coming from the driver's side of my ...
01-31-2009, 12:46 AM #1
BAD knock...even when warm *VIDEO*
Just tonight I discovered a really bad knock that seems like it is coming from the driver's side of my engine towards the back. Does it when car is warm or cold. You can really hear when the rpms are falling down after revving it a little bit. Sounds like it is coming from towards the top of the engine but I can't tell for sure. I'm not really sure what a bad lifter sounds like but just guessing this sounds like a worse knock. I'm about 99.9% sure its not an exhaust leak....plus its very loud and more mechanical sounding. Also Im pretty sure its not a bent pushrod just because its such a "heavy" knock. Also, oil pressure doesnt seem to fluctuate excessively or anything.
Heres a video to hear the sound. Theres not much to see cause its dark outside but you can really hear it. (Im holding the camera basically right above the driver head right in front of the cowl.
I'm very concerned that I'm looking at a bad engine knock or maybe something like a spun bearing. Any input would be greatly appreciated.
01-31-2009, 05:53 AM #2
just throwing out a guess or two.
any chance something got in your bellhousing (flywheel rubbing something)
flange gasket on your down pipe?
good luck man, i hate trying to chase noises like that
01-31-2009, 07:38 AM #3
almost sounds more isolated to the head (im hoping anyway)
also, its only on the driver side of the engine. I cant hear it at all on the left
01-31-2009, 07:52 AM #4
Sounds like a lifter from the video, but a lifter is more of tap than a knock. If its a bad knock like you say, its probably a spun bearing.
01-31-2009, 08:15 AM #5
any suggestions on diagnosing either???
More info from other thread:
yeah it is a tick noise but it almost seemed "heavier" if you know what I mean. No SES light.
Another thing, I went out this morning and it seems like it has quieted almost. Its not as prominent as it was last night. I listened to it from cold to running temp and now it seems it is more of a tick than a knock.
I attempted to long piece of alum curtain rod to see if I could pinpoint the noise like a stethoscope but the best I could do was determine the noise is coming from the back of the engine near the end of the header flange. Also, (trying to make sense of this but can't) I got the absolute most prominent tick when I would la the rod on either of the fuel rails.
01-31-2009, 10:09 AM #6
I saw its a lifter gone bad.
01-31-2009, 10:36 AM #7
Could THIS be my probelm?
hahah HUGE relief
01-31-2009, 11:30 AM #8
Before you do anything else, check to make sure that your plug wires are connected.
If one is off, it will knock like hell. If those are tight, swap out the plug wires for giggles to make sure that the plug wires are taken out of the equasion.
Hope that helps,
01-31-2009, 11:31 AM #9
Shit, didn't see the header bolt missing....lol. yeah, that's where the bleed air knock is coming from.
01-31-2009, 11:37 AM #10
not to mention the huge tear in the gasket
01-31-2009, 01:46 PM #11
01-31-2009, 02:17 PM #12
Yea rod knocks are constant they don't stop or even get quiet durring a rev. Lifters can knock at idel and go away with more RPM's and when the engine warms up. a truley BAD lifter is going to make a light knock compaired to a rod knocking. LOL I had a 85 Iroc that blew header gaskets just about every month. So was the bolt missing? if so where did it go? or why would it have backed out?
01-31-2009, 07:09 PM #13
02-01-2009, 12:39 AM #14
02-01-2009, 07:45 AM #15
02-01-2009, 07:56 AM #16
BTW....anybody know tq specs for the valve cover bolts.....too lazy to look it up
02-04-2009, 03:56 PM #17
Those gaskets will do it, i never use gaskets that come with headers and make sure i dont give it to the mechanic who is installing them i go and buy the OEM ones and just give it to them with my headers. The ones they give you with the headers especially pacesetter is almost certain it will leak. Well glad you found your problem, your lucky its not bad and hopefully the shop will get you OEM ones this time and install them for you.
02-04-2009, 09:09 PM #18
Already talked to the shop. He gave me the bolt for free but Im gonna have to hunt down gaskets myself. Do you know where I can find some OEM for cheam?? Dealer wants like $40 for both. Also, if I can just buy another paper one, will it hurt to just do the one side or should I do both at the same time? One more thing--anti-seize on the header bolts???
02-05-2009, 12:33 AM #19
04-07-2009, 05:09 PM #20
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