z-maro

iTrader: (18)

Well I changed my oil, and this is what it sounded like when I started it up. I haven't noticed the sound much before. Is this the standard LS1 piston slap that everyone speaks of?

ULTIMATEORANGESS

iTrader: (4)

that sounds nasty. like a rod knock.


i hope im wrong.

z-maro

iTrader: (18)

...I hope so too. Any recommendations on how to diagnose?

ULTIMATEORANGESS

iTrader: (4)

do you hear that all the time?

z-maro

iTrader: (18)

Just noticed it today, possibly a little before I changed the oil, then with the hood open I really noticed it after changing the oil. I have ran just one tank of fuel through it this year, 64k miles on the car. I just put in CAM2 blueblood synthetic blend oil that I won in it. 10W-30.

ULTIMATEORANGESS

iTrader: (4)

what brand and weight were you previously running?

RevGTO

iTrader: (12)

The key is whether it goes away when the car warms up. A friend's TA has piston slap so bad that it sounds like rod knock. But drive it around a couple of blocks and it goes away. The car is a strong runner and definitely is not suffering from rod knock.

ULTIMATEORANGESS

iTrader: (4)

yea,its hard to tell without hearing it up close. but some cars do have violently loud piston slap but overall its harmless despite what some claim.

z-maro

iTrader: (18)

I can't say for certain what I was previously using, I would guess valvoline 5w-30. Napa gold oil filters. The The crappy cell phone video could be making it sound worse, for example in person I'd doesn't have that sucking sound. The tick is pretty noticeable though, and was worrisome enough for me to make this post...

Also it definitely didn't make this noise a week ago, and I haven't been running it hard.

Edit: not that it probably makes any difference, but it is an 01 with the LS6 block from the factory.

ULTIMATEORANGESS

iTrader: (4)

its just weird you say it got louder after you changed your oil so i wonder if the brand and weight might be contributing to it being louder.

z-maro

iTrader: (18)

I have never noticed it before, so I wouldn't exactly say it got louder. It was very smooth and quiet before.

The oil says it is not for use in passenger cars or trucks, it's a high performance oil. I think TheAlchmist runs it, when I asked about the "not for street cars" before I'm pretty sure he said it was due to the additives being bad for cats. I have LT's and an ORY so I wasn't concerned about that.

RevGTO

iTrader: (12)

Yours doesn't sound like piston slap. I've noticed piston slap getting louder or quieter with different oils. But on my car at least, this time of year it has no audible piston slap. On a cold winter day, it sounds like a diesel.

It might be lifter tick, which tends to sound deeper and louder on these cars compared to traditional V8's. But like I said, if it doesn't go away when the car's warmed up, it's something other than piston slap.

redbird555

iTrader: (14)

not necessarily, not saying the op's is piston slap but the original ls1 in my car slapped cold, warm hot it didnt matter. i beat the crap out of that thing too and it always ran fine. some are just quiet others not lol

z-maro

iTrader: (18)

Well I decided to not drive it to work today. When I get home I'll check the header bolts and plugs to make sure they are tight and it isn't something stupid like an exhaust leak. I'll also see if it goes away when it's warm. I'll report back what I find, thanks for the help so far!

Also it might be hard to tell in the videos, but it seemed to go away for a while when I would blip the throttle slightly.

RockinWs6

Relax its lifter noise.................... do as I tell you or suffer with the noise until all the air bleeds out of the lifters.

Go buy some TransX transmission sealer AND some Lucas Synthetic oil stabilizer. Add 3 ozs of the TransX and 1/2 qt of the Lucas.

When you changed the oil filter you drained the lifter gallery and now the crappy GM lifters are full of air. So they tap and knock and scare the pants off you and your sister.

Do as I told you OR drive it until the air bleeds out....................

z-maro

iTrader: (18)

Here is another 2 videos. I drove it about 6 miles around town, it was up to full operating temperature. The noise is very hard to hear inside the car and is really only noticeable with the windows down and when the car is under very low load like coasting into a stop sign.

It almost seems like it could be the tensioner pulley. Putting a broom handle up to it and listening, it is way louder than the heads/block



I hope this is the case and it fixes itself. About how long before the air bleeds out in your experience?

RockinWs6

Now this sounds completely different that the 1st video, I'd check the water pump alt tensioner bearings.

z-maro

iTrader: (18)

What would be the best way to do that? I could take the belt(s) off and run it for a short period and see if the noise is still there.

Also FWIW I replaced the harmonic balancer with an ATI 10% UDP last spring, and used gatorback V-belts.

RevGTO

iTrader: (12)

Yep, you could try that. I've had water pump bearings going bad that were really noisy like that.

RPM WS6

iTrader: (3)

If it was never there before, at all, then it's probably not piston slap. Different brands/weights of oil can effect the severity of piston slap, but in general it won't ever go from being totally quiet to having significant slap with just a minor change in oil grade (like a 5w30 to a 10w30, as you mentioned doing.)

Having said that, some of these engines have pretty bad piston slap and will continue slapping at idle even in warmer outside temps. My '02 car would slap at just about any ambient temp below 70°F until the engine was fully warmed up (meaning driven for several miles), and in cooler temps it would slap at idle no matter how long it was driven. When the outside temps got well above 70°F, it wouldn't slap at all - totally quiet. That's how it always was, never got any better or worse and didn't change much at all using oil grades between 5w30 and 0w40.

High ZDDP content oil is supposed to be bad for cats, this is one part of the "not for street cars" designation. The second part is the fact that some of these "racing only" oils have a very low detergent level, thus can't be run for more than 500 miles or so before a change is needed. I would check with the manufacturer about which category this oil falls into. For example, Valvoline makes a couple different "racing" oils, one is the VR1 brand and the other is an "NSL" version (Not Steet Legal) - the NSL version needs to be changed at 500 mile intervals, while the VR1 has a more typical detergent level and can be changed at 3k mile intervals. Yet, both oils have ZDDP content high enough to not qualify for GF-3/GF-4 or higher (these are ratings for the reduced ZDDP content oils current used in normal stock street cars) ratings, so it's best to check the details on these specialty oils.

The videos posted don't really offer sound quality high enough to properly diagnose anything, but it sounds more like pulley noise than anything else, to me at least. Tensioner and idler pulleys tend to be the most failure prone, but really any of the accessories could be making such a noise.