Engine Ticking Noise After Timing Belt Swap

My girlfriend has an 05 Aveo with 110k. Recently decided to do the timing belt after it developed a slow knocking noise from the timing cover. This is what greeted me when I pulled that top cover. I watched as the belt went around the sprockets and the broken part slapped the timing cover. I thought I was in the clear since I had found my noise (and before it let go). The exhaust cam may have skipped one tooth as a result of the last belt (or the belt slackened enough to make it appear that way), but it's definitely lined up now.

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I'm not a mechanic, but I have been wrenching on cars as a hobby since I was younger, so it was something I was able to tackle. I followed the solid guide I found here, thanks for that!

Now when it runs it has a different knocking noise that's much higher pitched and faster. I grabbed a compression gauge thinking it must have bent a valve and THAT was the knocking noise instead. The compression was (1-4): 203, 210, 210, 201. It runs fine beyond the ticking noise. That doesn't really say bent valve to me. I would hate to pull the head for no reason. I did the head gaskets on my Grand Prix and am not looking forward to a repeat, even though its only one head this time.

Anyways, I had to wait for a replacement rear timing cover to come in so the car sat apart with the valve cover off for a few days, obviously covered up though. I'm hoping it's just a stuck lifter. Check out the video and see if you have any thoughts. At the end of the video you can hear it change pitch slightly.https://youtu.be/DBNdLomNNdk

I'm thinking either stuck lifter, exhaust leak, bent valve, or a thrown bearing. I just don't want to to tear into it for no reason.

If anyone is curious... I think the timing belt failed because someone else used the "pull the rear timing cover forward to get the water pump out" method and cracked it in several places no longer holding it against the engine firmly. I could see that it was rubbing the idler pulley because the pulley and the cover had matching marks clearly showing they were making solid contact. The rear cover basically disintegrated when I pulled it off as well.

Thanks!

Have you tried running it for a (very) short time with the serp belt removed to see how much (if any) of the noise goes away? If not I'd try that next. Then if most or all of the noise remains with the serp belt removed, try a mechanics stethoscope to see if you can pinpoint the source. Highly doubt a bent valve with those numbers, and there have been almost no reports of spun bearings with these engines.

Actually that video has the serp belt removed. I noticed the serp tensioner pulley needs replaced before I slapped it back together. I was hoping maybe I would get lucky and that would be the problem, but no luck. I wanted to make sure it works before I replaced that.

I don't have a mechanics stethoscope but I did try a similar thing with a long screwdriver earlier. I can't hear the noise when I touch it to the valve cover at all. I also poked my head underneath to see if I could hear it from the oil pan and nothing. The only place I can really hear it is through the screw driver is on intake side poking around the fuel rail, but it's not really that loud there either.

I looked in through the passenger wheel well to see if something might be knocking outside the engine but didn't see anything. The only thing I did notice was that it reeked of exhaust in there. That made me think exhaust leak, but it just sounds so metallic.

I guess my next step is to pull the timing cover off again and make sure everything is tightened and not knocking there.

Agree that's a lot of noise. My '05 with 144K and my daughter's '06 with 100K are both very quiet. I'm wondering about sludge. Do know the complete oi change history of her Aveo? How does the oil look now?

From the video, I am going with some kind of exhaust leak. Yeah it's noisy.

It definitely wasn't this noisy before all of this happened. So this is a new development.

For the most part she has kept up with her oil changes. The current oil change is at definitely the end of it's span. I planned to change it once I'm sure everything is good. Inside the valve covers didn't look too bad as far as sludge.

My mechanic buddy wants me to toss in some engine cleaner and see if it could be lifters. I'm leaning towards sludgy lifters or exhaust leak myself.

Quick update:

I went out this evening to fire it up again and the noise is completely gone. I gave it a spin around town and it's completely silent! I guess that confirms a stuck lifter that finally pumped up.

Thanks for the help!

Thank you for the follow up! A lot of times the problem is resolved but no final words ....