The car is an 01 Z28 (M6) with bolt-ons and an F13 cam, 99k miles on the odometer. This ticking developed a few days ago on my way to work. I've done several searches on here and youtube comparing this noise to common noises (belt tensioner, lifters, pushrods), but none of them sound the same as this one to me. The noise is there all the time (idle, acceleration, deceleration), and varies according to the rpms. Any guesses where I can start to look?

I changed the oil today, it did not smell burnt and there were no metal shavings in the oil/plug, oil pressure is good. I haven't ruled out belt/pulley issues, but I wasn't sure how to test for that (I can't start the engine with no belt, can I?). My next idea is to pull the valve covers and check the valvetrain, see if anything looks out of the ordinary.

I can't really afford to take it to a mechanic right now, so any help is greatly appreciated!!!


2/09 UPDATE: Ran the engine with no belts, but the noise did not change. Pulled the valve covers and checked the valvesprings/rockers/pushrods. I couldn't find anything damaged, all seems to be in good shape. I guess the next thing to check would be the lifters.

2/28 UPDATE: A few days after this video was taken, the noise actually became much quieter than what you hear in the video, but it was still there, particularly during deceleration. With the help of a local, we used a stethoscope to isolate the noise to the driver's side of the engine. He told me it was likely to be either the rocker arms, or a bad lifter. So, I pulled the valve covers on that side and pulled the rocker arms, but they all looked normal. I also checked all pushrods and each valvespring individually, but everything checked out. So at that point, I decided to pull the heads and check the lifters. (I meant to run the engine with no valve covers, but I forgot and didn't remember until I was halfway through removing the drivers side head) After pulling the heads, I replaced all the lifters on that side with a set of used ones that another local buddy of mine gave me. Put it all back together, started it up, and the noise was gone. Ran it for a few minutes, changed the oil (nothing out of the ordinary there), and I've been driving it since with no problems or noises.


http://www.youtube.com/watch?v=eHsz7qStdlA

 

Sounds like something VERY internal. Subscribed. Wouldnt drive it or run it much till you figure it out honestly.

 

doesnt sound like a belt issue at all. sounds like maybe a colapsed lifter! Hopefully. you can run the car without a belt for short amounts of time as you will not be turning the alternator and running off of the battery and you wont be turning the water pump so there will be no cooling. anyways pull the valve covers and inspect rockers,pushrods for damage. if no visible pull the head and start looking at lifters. if all else fails maybe a rod bearing. im sure someone else will chime in. hope all goes well.

 

if its an auto check torque converter bolts one maybe loose or all

 

I forgot to mention, the car is a M6.

I have the day off tomorrow so I'm planning on pulling the valvecovers then and checking the valvesprings/rockers/pushrods. I'll keep you all updated. Thanks for all the suggestions so far!

 

Holy **** that was loud!! I had a collapsed lifter, and while it sounded similar, it was never ever nearly that loud. Good luck finding the culprit

 

Sounds like something in the valvetrain. There is also a dead miss which could mean you have a broken spring. I would not run it anymore until you pull it down and inspect everything.

 

to me sounds like a lifter. I would pull the heads and check everything before driving the car. Might lead to more damage. Was anything in the valvetrain replaced when the cam was done???

 

Valvesprings, seals, and pushrods. They all have about 40k miles on them, so its probably about time for a checkup anyways.

 

i'd say its time for some new parts. Hopefully thats all the noise is something that can be replaced without too much damage to the wallet

 

If a lifter was collapsed, couldn't he check with a dial indicator or compare known locations? Just in case it is not, that way he doesn't have to pull the heads yet.

subscribed

 

^^this may work to. Bad thing about these cars is that heads need to come off to replace lifters though ;(.....

 

when I was having my car tuned & dynoed i had a set of lifters collapse and tuner said it sounded like yours.

 

^^^sorry not a set but a lifter

 

Pull the valve covers first, it's the easiest thing to do. Check all the valve springs, seats, and the rockers, make sure none of them have any extra play in them or are broke. Then pull off the rockers and start pulling pushrods, it's possible some of them may have bent.

After you do all this and nothing is found, it's time to pull the heads and replace the lifters. Hopefully it's just a pushrod for your sake, as I'm sure nobody just wants to pull the heads.

Good luck

 

Well, I popped off the valve covers this morning. I went through and checked the valvesprings, rockers, and pushrods. Everything looked good, I couldn't see anything cracked/bent/broken. I didn't pull the heads off the car, so the back springs on the passenger side were very difficult to inspect with the limited amount of space, but from what I could tell nothing was wrong. I also ran the engine with no belts, but the noise did not change. I guess the next thing to check would be the lifters. I'm going to have to wait until the weekend to dive into that project, since I've never pulled the heads off before and I want to do it with plenty of time.

Any chance that it could be anything else other than a bad lifter? I'd hate to go through all that work and put it back together only to start it back up and hear that damn noise again!

 

Did you rotate the engine by hand to see if maybe a lifter was collapsed, dial indicator, anything like that? I would hate to pull the heads to find out the lifters are fine...

 

It could be a bad lobe on the cam, but that would still require pulling the heads. If the cam lobe is shot then the lifter will be trashed as well. Just make sure all of the pushrods are straight before pulling the heads off.

 

does the noise do it 100 percent of the time or only worse after warm up i have had cars come in the shop before and sound similiar to this and it be a rod ...doesnt sound like tipical rod knock but if it gets worse as it warms up its prob a rod ...just something to think about...

 

I did not try to rotate the engine, I'll do that next this weekend before I pull the heads. The noise is there 100% of the time, it does not change at all after warm-up. At this point I'm thinking either lifter or cam. I think my next step will be to pull the heads and see what I find. If I find a bad lifter, will I need to pull the cam as well?