nathanVY

Hi everyone, have noticed some odd noises coming from ls1 over the past few weeks. It's a 2004 with roughly 110,000kms on it, it's been boosted for about a month, has lunati double valve springs, arp head studs and ls9 head gaskets, other than that stock.

It seems really moody, some days it'll not make any noise. Most times when started it can hardly be heard, need to stick your head under the near (near the drivers door) and it sounds like it's coming from the bell housing / rear of motor area.

The key part when it's the loudest is when the car has been driven at operating temp for a while, parked and left for 10-15 minutes then started again the rattling gets louder then.

Currently running Penrite 10W40 Racing Oil. Few things it could be hoping you guys can help me narrow it down:

- Lifters
- Main / Rod / Cam bearings
- Spigot bearing
- Throw out bearing
- Flywheel bolts loose
- Something else gearbox or clutch related
- Water pump (the only accessory that hasn't been replaced, have started without a belt on though and noise was still there)

Any help much appreciated, thanks.

SCHP98ls1B4C

iTrader: (2)

If you didn't use a factory GM throw out bearing most likely the new after market you put in is loud. Don't worry about it just drive it and enjoy it.

03Sssnake

iTrader: (20)

I agree.... Does the noise go away when the clutch is pushed in? When the TOB is the culprit, it will usually quite down when pushing the clutch in.

nathanVY

Yes TOB/Slave Cyl is after market, almost a year old. If it's gearbox related I couldn't care less, it can rattle away until the clutch stops working and i'll pull it out and replace it all.

If it's not gearbox related (e.g. bearings), I'd rather tear down the motor now and inspect before there's any major damage, don't have to have to go get a new block because of a spun bering. That's my only concern really, I'm looking at putting a cam kit in it soon, new lifters, oil pump, timing chain, etc etc.

SCHP98ls1B4C

iTrader: (2)

Don't tear it down its your throw out bearing.

99Bluz28

iTrader: (35)

Yes, X 2 !

My car made the same noise under almost the same condition when my throw-out bearing went on a diet a tossed its bearings.

nathanVY

Well that's reassuring! Throwout bearing I would have liked to replace when I last did my clutch, it was about 2-3 months old with the slave cylinder I put in a second hand clutch with my manual conversion - that clutch munched its self at the drags, pressure plate split.

So question about the throw out bearing noise, wouldn't putting the clutch in or putting the car in gear (on stands) make this noise disappear or change? and does it make sense that it comes back loudest when started hot?

Thanks for your help!

SCHP98ls1B4C

iTrader: (2)

Normally they quiet when you push the clutch in, but if it's really bad sounds like it is they make noise almost all the time it's a bad bearing. If you replace it use a new GM throw out bearing and pilot. Yes bad throwing out bearings tend to be louder as everything comes up to operating temperature.

nathanVY

Thanks, here's a video of the noise. All engine belts are off so that should rule out any accessories. This pretty much cold start car hasn't heated up yet.

I've pulled both valve covers off, valve springs and rockers all look fine. Also put the rear on stands and put the car in gear, the rattling didn't change at all, doesn't seem to change when you put the clutch in either.

nathanVY

After doing few things and going for a quick drive to warm it up this is the result, listening through a piece of hose in certain areas you can hear a tick on some exhaust pipes, and a light tick through the oil fill cap, but you can't hear anything at all outside unless you use a hose.

All i've done is

- tightened turbo flange bolts
- tightened header bolts on both sides
- tightened crossover pipe bolts
- added some more oil, it wasn't low on oil according to the dipstick but i've heard some ls1s enjoy a little extra oil, haven't added much maybe a few hundred mls.
- bled clutch

will see what it's like over the next few days I guess. Thinking it could be an exhaust leak? It does look like the turbo housing has knocked the strut tower in a bit, perhaps that has resulted in a cracked manifold somewhere.

nathanVY

Well the rattle is back today. Anyone have ideas? Thinking I might do an engine flush and some fresh oil..

mthomsen224

Any chance it's the timing chain? In your first video it kind of sounded like it had a bit if a rythem to it. Kind of hard to pin point in the video and I could be way off. Just my $.02. I hope it all works out.

nathanVY

Yes I was thinking that, you're right it's not continuous like a lifter or something else would be only happens every few seconds. May well be the timing chain, it will be the factory timing chain and probably won't be getting an easy life with an extra 120+rwkw getting pushed through it.

I'm looking at putting in a cam kit soon which will include a new billet timing chain, oil pump and a few other things. I guess that's all I can really do - is there any way to check bearings, rods, etc with the heads off and the cam out? I just want to be certain the bottom end is good before I put it all back together.

mthomsen224

None that hit me right off hand, but there are a lot more knowledgable people around here that may have some tips and tricks I don't know. I hope it all works out for you.

svede1212

iTrader: (3)

What special place is the OEM TOB made at? I've seen my OEM next to an aftermarket and they had the same casting marks and everything on them. I believe there are only 2 or maybe 3 manufacturers.

98_1LE

iTrader: (17)

My car developed a rattle that sounded like it was coming from the bellhousing, but up on stands with a stethoscope was inside the trans. Turned out 5th gear had worked loose on the shaft. The shaft had to be welded up and turned back down, plus a trans rebuild. Hopefully that isn't your issue.

nathanVY

Yeah it can't be heard further back in the gearbox.

Changed oil and put some engine flush through, went from Penrites 10w40 racing to HPR10 (10w50) and it seems to like that one a lot more. No funny noises at all so far and car runs great. Will wait and see if the noise comes back I guess.

Still the plan is to put a cam kit in in a few months, new lifters, oil pump, timing chain etc. Thanks all for your help will post if it comes back.