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Discussion Starter #1
This is my first posting on this site and I'm looking for a little help.

I have a mildly modified 2008 TBSS that has developed an annoying ticking sound. It's somewhat noticeable at idle, and more so when driving around 2k rpm when backing off the throttle or at neutral throttle.

The vehicle has about 124k miles on it. About 25k or less miles ago, it had a custom grind cam installed with all aftermarket HP beehive springs, Howards pushrods, rocker trunnion kit, drive gear, etc. Also a oil pickup relocation, LT headers, exhaust, CAK, etc. My first thought was a bad/collapsed lifter, bent pushrod, broken spring, worn lobe or something valve train related. I pulled both valve covers and all the springs looked good. I turned it over manually several times and checked all of the rockers for extra play and everything looked and felt tight. No indication of valve train issues. I spent quite a bit of time with a stethoscope trying to diagnose it, and couldn't find anything obvious. The internals sounded fine. The injectors make quite a racket, so it could be one of those, I suppose. I couldn't find an obvious header leak, but there could be one that I can't detect at idle. The performance seems fine. Idles well, doesn't stall, runs strong.

I'm at a loss as to what it could be and wondering if anyone else here has experienced this. I'd really appreciate any thoughts you might have?

Thanks in advance!
 

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2008 TrailblazerSS
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This is my first posting on this site and I'm looking for a little help.

I have a mildly modified 2008 TBSS that has developed an annoying ticking sound. It's somewhat noticeable at idle, and more so when driving around 2k rpm when backing off the throttle or at neutral throttle.

The vehicle has about 124k miles on it. About 25k or less miles ago, it had a custom grind cam installed with all aftermarket HP beehive springs, Howards pushrods, rocker trunnion kit, drive gear, etc. Also a oil pickup relocation, LT headers, exhaust, CAK, etc. My first thought was a bad/collapsed lifter, bent pushrod, broken spring, worn lobe or something valve train related. I pulled both valve covers and all the springs looked good. I turned it over manually several times and checked all of the rockers for extra play and everything looked and felt tight. No indication of valve train issues. I spent quite a bit of time with a stethoscope trying to diagnose it, and couldn't find anything obvious. The internals sounded fine. The injectors make quite a racket, so it could be one of those, I suppose. I couldn't find an obvious header leak, but there could be one that I can't detect at idle. The performance seems fine. Idles well, doesn't stall, runs strong.

I'm at a loss as to what it could be and wondering if anyone else here has experienced this. I'd really appreciate any thoughts you might have?

Thanks in advance!
Did you check your plug wires?


2008 TBSS Super Charged
 

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Discussion Starter #4
That's a good question. I have not, but #2 boot is very close to the header. It could be arcing. I'll take a look at it tomorrow. Thanks!
It looks like it's not a spark arc. I'm using good MSD wires and boots with ceramic coated headers, so that seems fine.

Thanks, though. Any other ideas?
 

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07 tbss awd
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Are you sure it’s an engine noise?

Does it change at all when the engine is hot vs. cold?

Can you take a video? That might help us figure out exactly what noise your dealing with.
 

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Discussion Starter #8
Are you sure it’s an engine noise?

Does it change at all when the engine is hot vs. cold?

Can you take a video? That might help us figure out exactly what noise your dealing with.
I’ll try. It’s hard to pickup on a mix, but I’ll see what I can do. Thx
 

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At 2k or above... Rod bearing. Common problem on LS2 with the front oil pickup position. You need to pick up a set of pcmofnc oil pickup baffle and pickup relocation kit, and a good set of bearings. If the motor was always in your possession and never rebuilt, get standard. If it's been out... You'll need to see what's in it before you order. Clevite has a great set of coated bearings. Install a set of ARP rod bolts while you're in there, and she'll live another day
 

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This is my first posting on this site and I'm looking for a little help.

I have a mildly modified 2008 TBSS that has developed an annoying ticking sound. It's somewhat noticeable at idle, and more so when driving around 2k rpm when backing off the throttle or at neutral throttle.

The vehicle has about 124k miles on it. About 25k or less miles ago, it had a custom grind cam installed with all aftermarket HP beehive springs, Howards pushrods, rocker trunnion kit, drive gear, etc. Also a oil pickup relocation, LT headers, exhaust, CAK, etc. My first thought was a bad/collapsed lifter, bent pushrod, broken spring, worn lobe or something valve train related. I pulled both valve covers and all the springs looked good. I turned it over manually several times and checked all of the rockers for extra play and everything looked and felt tight. No indication of valve train issues. I spent quite a bit of time with a stethoscope trying to diagnose it, and couldn't find anything obvious. The internals sounded fine. The injectors make quite a racket, so it could be one of those, I suppose. I couldn't find an obvious header leak, but there could be one that I can't detect at idle. The performance seems fine. Idles well, doesn't stall, runs strong.

I'm at a loss as to what it could be and wondering if anyone else here has experienced this. I'd really appreciate any thoughts you might have?

Thanks in advance!
I had the same exact problem, and I think it’s the o ring on my pick up tube that goes to the oil pump. I pulled the dipstick when it began to tick and there was air bubbles in on. Your oil could be whippin up
 

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Discussion Starter #15 (Edited)
I took a harder look at it last night and I'm thinking rod bearing. Still could be lifter related, roller pin slipping out or something like that, but when I revved it to the noise sweet spot around 1600rpm, I could pick it up with the stethoscope in the block. It's more noticeable when the engine is warm and almost non-existent when cold. I'll attach a video I took last night where you can hear it pretty well.

It hasn't gotten much worse since it started a few months ago, but I suspect a rebuild is in it's future. It sounds metallic. Oil looks fine. I'll probably run it until things warm up around here if it'll make it and make a decision then what to do about it. I got rid of most of my stuff for this kind of work when I moved (engine stand, cherry picker, space), so I'm not sure if i want to pull it. Might just sell to someone who wants a project. We'll see. Let me know what you think, and thanks for all the responses!

TBSS Noise
 

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07 tbss awd
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Cut the filter open and look for metal. That should tell you whether or not it’s internal bearing related or not.
 

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Discussion Starter #17
Cut the filter open and look for metal. That should tell you whether or not it’s internal bearing related or not.
I will. I'll be changing the oil to check that out and move to something a little thicker while I'm at it. Thx
 

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Did you replace your lifters during cam install?? I’ve seen where a Cam bearing spins and takes out nearest lifter and cam lobe causing tick but looking like it’s going to need some tear down to find condition
 

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Discussion Starter #19
I changed the oil and put in some 10w-30 and oil treatment to preserve/extend what I can. I split the filter open and there were very small fragments, mostly dust size and some a bit larger. Some were responsive to a magnet. Not as bad as I expected, though. I suspect a rod bearing heading south. I'll pamper it to get through the winter and decide whether to keep and rebuild or sell at a significant discount to someone looking for a project. Just not sure if I feel like doing the work. It's otherwise in nice shape and has some good upgrades (suspension, remote start, stereo, wheels, etc). I love the platform, so I'd probably just buy another in RWD instead of AWD. Thanks again.
 

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07 tbss awd
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Kind of a bummer, but if you do decide to keep it... a little stroke and a stronger bottom end will probably make you love the truck even more!
 
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