2001 WS6 - Knock while at idle

**cpellens** · 10-09-2015, 05:43 PM

Hi, everyone. My 2001 WS6 is making a knocking sound at idle. Sounds like it'd be just from one cylinder? But it starts at idle but when you give it gas, it goes away. When it gets back to idle RPMs, it doesn't come back for about 6-7 seconds. Could this be too thin of oil? Bent push rod? Lifter? Valves? Kind of wanted to get an idea of what's going on before I get into it lol. I appreciate any help or input.

**pajeff02** · 10-10-2015, 04:46 AM

Sounds an awful lot like a lifter -- high pitch or low pitch knock?

**RONS98TA** · 10-10-2015, 05:49 AM

Try to get a video of it. That would help us out a little. Sometimes it's really deceiving where some noises are coming from. I like to use a metal rod up to my ear, and touch different places on the engine while its running and knocking, to get a better idea of where the noise is coming from. Try touching the valve covers in different spots, and then under the car on the side of the block and oil pan. NOW YOU NEED TO BE EXTREMELY CAREFUL WHILE DOING THIS! The exhaust and moving parts will try to "bite" you while doing this, so take your time and please be careful.

**pajeff02** · 10-10-2015, 08:06 AM

A long piece of wood also makes a great sound magnifier when pressed to the engine and your ear.

**cpellens** · 10-11-2015, 02:42 PM

Here's my video. It's quiet, but you can hear some weird ticking that sounds like it's coming from one cylinder. Notice how it's gone after the rev for a few seconds.

I came across this video where the ticking is a little louder but sounds the same.

**pajeff02** · 10-12-2015, 04:53 PM

Looks like your PCV hose is cracked open in the top vid -- might want to check that.

Hard to tell... what is your oil pressure at idle? Is the noise the same whether the engine is cold or warmed up?

**jcivtec** · 10-13-2015, 12:43 AM

My 02 SS has a very similar noise.. Please post if you find out what the problem is.

***SMWS6TA*** · 10-13-2015, 08:21 AM

Take a piece of cloth and run it by the exhaust manifold and see if it's leaking.

That could be a collapse lifter or a loose rocker. Really hard to tell. You can pull the valve covers off, put it at TDC for that cylinder and check each rocker looking for one that has play between the pushrod and rocket. There should be none (Don't confuse with preload).

Another way to check and it's a little messy, is while the covers are off, hook the coils back up and start it. I used cardboard to help contain the oil splashing off the rockers. You should see oil coming from the pushrods lubing the rocker. If not - lifter has collapsed or clogged.

**cpellens** · 10-14-2015, 07:55 PM

Oil pressure stays around 25-30 ish at idle. The noise is there at cold start as well as when warmed up.

**pajeff02** · 10-15-2015, 03:17 AM

Ok - our engines are rather noisy when cold and that is very common. Warmed up though, it should quiet down so go ahead and try the redneck garage stethoscope method we talked about to see if you can narrow down a location in the engine where the sound is loudest.

**cpellens** · 10-15-2015, 09:15 PM

Alright I'll check it tomorrow and get back to you. Thank you

**cpellens** · 11-03-2015, 08:56 AM

Update: Sounds like it's on the passenger side. I put a funnel up to where the oil cap screws on and there was the ticking.

***SMWS6TA*** · 11-03-2015, 12:37 PM

Does it increase with a bump of the throttle?

**RONS98TA** · 11-04-2015, 06:17 AM

I'm thinking it's louder near the oil fill due to the opening of the cap acting as an amplifier. Your in Michigan, it's cold. I don't think you're noise is anything out of the ordinary. Might try the next step down in oil viscosity. I'm thinking the oil is just thick at cold start up, then thins out as it heats up. The top end of the engine is noisy until the oil gets completely circulated. This is just a guess though. You're best bet is to make sure you have oil flowing over the rockers while it's running. Messy as hell, but better safe than sorry.

**johnfin** · 11-05-2015, 06:44 AM

Its a common problem: Piston slap

FYI: a "cure" for the LS1 piston slap?? - CamaroZ28.Com Message Board

**cmierobf** · 12-02-2015, 06:07 AM

for the LS-1 tick I use LUCAS Synthetic Oil Stabilizer ...

**cammed goat** · 12-02-2015, 06:22 PM

Sounds like a leaking exhaust manifold gasket to me.

**SuperSSguy** · 12-02-2015, 07:16 PM

My guess would also be piston slap....Yes as stated above this was VERY common, although some were lucky enough to NOT have it...and if it is piston slap theres no magical potion to cure it..Just get a loud exhaust and turn your music higher

: You could also opt to have it re-sleeved or get another LS but c`mon? It sucks I know- i read an article back a few years ago that was written by a guy who was a former GM Tech and he was strongly advised by the top dogs of the dealerships to NOT replace engines that had piston slap unless the customers really really threw a fit and were totally irate,then maybe.....Most with this problem did complain but were given the run around over and over until they just went away frustrated!! ...NOT a good way to do business or good for GM`s customers but hey what the hell did they care they got your money right?.....