Attention LS gurus - I have Engine Gremlins

**mxplane123** · 12-15-2009, 04:57 PM

Put on your thinking caps men, this one's perplexing. I have a 2002 WS6 collectors edition with 50,000 miles and just changed the oil: conventional 5W-30. Cannot find out what kind of oil previous owner used. Drove smooth with no noises. After oil change, I drove it 20 miles and upon entering driveway, noticed a rattling/clicking noise from engine area. Sounded like a cross between bad bearings and valve clicking. Most noticable when eng revs downward -- between 2000 and 1000 RPM. Went to Chev dealer the next day and I'll be damned if it did'nt run smooth after I got there -- I took a tech for a drive and there was no rattling or clicking of any kind. I'm sure the engine gremlins were laughing it up, having made such a liar out of me. Tech said that during oil change air may have gotten into eng/valve area and when I floored it on the way to dealer it cleared everything out. Drove car home again and the gremlins returned -- more rattling and clicking although not as loud. My fellow gear-head friend says it could be.... bearing on the water pump or air conditioner or other bearings starting to go bad, or maybe mech dropped something into engine during oil change and it shifts location during driving-- accounting for the on and off again noises. Anyone out there have any suggestions? This things driving me up the wall. Thanks in advance.

**c5z28** · 12-15-2009, 05:09 PM

My car when it is cold has a lifter tick right at 1600rpms when it is cold. If it goes away when it warms up it is either lifter tick or piston slap. What oil did you use? Post a video of the car making a noise.

**Phantom2kz** · 12-15-2009, 05:13 PM

Oh .. i need more then that.... does it miss,or hesitate when making this noise? any lights on?
is this a M6 or A4?
it could be cats coming apart.
it could be a belt tensioner, belt noise. louder or changes with A/C on or off?
it could be a cracked flywheel/flexplate.
it could be U-joints if only happens in motion.
Had Enough?

**croslod** · 12-15-2009, 05:31 PM

I don't know about anyone else, but since owning my current 00 ta the noises have been driving me nuts, engine sounds like a duramax at cold start up and has a ticking sound after it gets to temp,rear end always whines and makes funny noises when i slow down and turn and tons of rattles on the inside. My new motto is turn up the radio and drive it till it blows. Good luck.

**0rion** · 12-15-2009, 05:41 PM

Originally Posted by croslod

I don't know about anyone else, but since owning my current 00 ta the noises have been driving me nuts, engine sounds like a duramax at cold start up and has a ticking sound after it gets to temp,rear end always whines and makes funny noises when i slow down and turn and tons of rattles on the inside. My new motto is turn up the radio and drive it till it blows. Good luck.

you'll be driving that thing a long time. It's a well known fact that the LSx engines love to clatter and make all kinds of noise. It's also a known fact the rears in these cars are terrible. The upside is you can upgrade the rear when it blows and the LS1 makes tons and tons of reliable power and still gets great gas mileage. It's a performance car so it's not going to be quiet like a family sedan.

**0rion** · 12-15-2009, 05:43 PM

Originally Posted by mxplane123

Put on your thinking caps men, this one's perplexing. I have a 2002 WS6 collectors edition with 50,000 miles and just changed the oil: conventional 5W-30. Cannot find out what kind of oil previous owner used. Drove smooth with no noises. After oil change, I drove it 20 miles and upon entering driveway, noticed a rattling/clicking noise from engine area. Sounded like a cross between bad bearings and valve clicking. Most noticable when eng revs downward -- between 2000 and 1000 RPM. Went to Chev dealer the next day and I'll be damned if it did'nt run smooth after I got there -- I took a tech for a drive and there was no rattling or clicking of any kind. I'm sure the engine gremlins were laughing it up, having made such a liar out of me. Tech said that during oil change air may have gotten into eng/valve area and when I floored it on the way to dealer it cleared everything out. Drove car home again and the gremlins returned -- more rattling and clicking although not as loud. My fellow gear-head friend says it could be.... bearing on the water pump or air conditioner or other bearings starting to go bad, or maybe mech dropped something into engine during oil change and it shifts location during driving-- accounting for the on and off again noises. Anyone out there have any suggestions? This things driving me up the wall. Thanks in advance.

your first step is to narrow down where the noise is coming from. You can put your ear to the handle of a long screwdriver and touch the tip around the pulleys and what not. If one of them is making a racket you'll definitely find it. A broom handle also works. Don't get your face caught in the belts though...would most likely hurt like hell.

If it's in the upper end of the motor find out what side. Like was previously mentioned....it could be a host of things and like I told the last guy. These motors tend to make some racket.

**mxplane123** · 12-15-2009, 07:58 PM

1. I used Valvoline 5W-30 conventional oil as per owners man.
2. It makes the rattling/clicking noise when cold or warm.
3. Does not miss or hesitate. It's an A4.
No change in noise when AC on or off. No (warning) lights or other lights.
Noise is coming from mid section or front of engine definitely.

SUMMARY: What puzzles me most is that it makes the rattling/clicking noise
then the noise goes away completely. On rare occasion the noise
will simply decrease in intensity. As the car has flowmasters its
hard to tell if it makes the noise at higher RPM, but its easy to
hear when engine is decreasing between 2000 and 1000 RPM.
Any opinion on if it could be items I listed in my original post?

**tep98ws6** · 12-15-2009, 09:19 PM

Hmmm... LS death rattle from pushrods?

Do you drive it hard or have you ever bounced off the rev limiter?

**SSTODD** · 12-16-2009, 07:56 AM

I vote for piston-slap, but it is not deadly as it sounds it is just the LS1design. Try a 10w-30 synthetic next time and a different brand oil and you will find one a little more quiet.

**SOMbitch** · 12-16-2009, 09:23 AM

Put a cam,headers and CB and on it and it will go away...I promise

**mxplane123** · 12-16-2009, 03:00 PM

I've driven it for 2500 miles since purchase and only accelerated hard twice -- below 5000 RPM. First 2200 miles it drove realitively smooth, no rattling/clicking.
Will prob put 10W-30 in next time -- but won't using synthetic oil after using conventional oil all it's life screw with engine?
The puzzling thing is that the noise is loud and it will later vanish completely. Didn't think Piston slap could come and go like that.
If I eventually have to sink $2000 or more in engine, I'll just buy a new crate eng -- prob the LS376/480, a normal LS3 with a hot cam (has 480 HP) and costs abot $6600.00. See http://www.gmperformanceparts.com/En...1224&engCat=ls
Still like more suggestions on the noise though. Thanks...

**0rion** · 12-16-2009, 04:27 PM

Originally Posted by mxplane123

I've driven it for 2500 miles since purchase and only accelerated hard twice -- below 5000 RPM. First 2200 miles it drove realitively smooth, no rattling/clicking.
Will prob put 10W-30 in next time -- but won't using synthetic oil after using conventional oil all it's life screw with engine?
The puzzling thing is that the noise is loud and it will later vanish completely. Didn't think Piston slap could come and go like that.
If I eventually have to sink $2000 or more in engine, I'll just buy a new crate eng -- prob the LS376/480, a normal LS3 with a hot cam (has 480 HP) and costs abot $6600.00. See http://www.gmperformanceparts.com/En...1224&engCat=ls
Still like more suggestions on the noise though. Thanks...

piston slap does go away when the car warms up. If it's doing it warm though it's not slap.

**SSTODD** · 12-17-2009, 02:25 AM

quote: Will prob put 10W-30 in next time -- but won't using synthetic oil after using conventional oil all it's life screw with engine?

No, do not worry about those old myths. Put in the best oil you can and a good filter also! Look at the "I'm an oil junkie" thread if you have time to read for a week

and see the great oil and filter discussion. To save you time the 10-30 Pennzoil Platinum synthetic or Amsoil synthetics are favorites and for filters try a Napa, Wix, or Amsoil filter. NO FRAMS.

**SteveC** · 12-17-2009, 03:55 AM

I have the same thing happening with my 01 Z28, it is a garage queen, never raced with 25K original miles. I use RP 10W-30, changed the oil @ 10K interval (not the brand), and I have a tick at deacceleration low RPM (when engine is warm). The vehicle runs great, no codes, full power.

I am not an expert on these vehicles, however in my case, I believe it could be a roller bearing noise from one of the pushrods, the sound is coming from the rear of the engine.

I had a mechanic listen to the engine, and he said he believes it to be the normal clatter these engines produce, and in time (if it is something worse) will produce another symptom.

SteveC

**402 Guru** · 12-17-2009, 06:21 AM

yes orion made a good point. these engies make all kinds of noise they are performance engines. If you hear a ticking it could be a bearing going out in the water pump(time will tell ) or a belt that is squeeking ,Just drive your car and have fun the engines. if you just have money to spend and dont like the performance you have now by all means .Get a crage engine and sell your other block on creigslist

. If you are not happy driving it then Upgrade Imo

**02blkws6** · 12-20-2009, 05:20 PM

Originally Posted by SteveC

I have the same thing happening with my 01 Z28, it is a garage queen, never raced with 25K original miles. I use RP 10W-30, changed the oil @ 10K interval (not the brand), and I have a tick at deacceleration low RPM (when engine is warm). The vehicle runs great, no codes, full power.

I am not an expert on these vehicles, however in my case, I believe it could be a roller bearing noise from one of the pushrods, the sound is coming from the rear of the engine.

I had a mechanic listen to the engine, and he said he believes it to be the normal clatter these engines produce, and in time (if it is something worse) will produce another symptom.

SteveC

I hope you're doing UOA with 10k intervals, esp with RP.

**DaddySS** · 12-20-2009, 05:41 PM

It sounds like you definitely have a pulley, accessory bearing, etc. noise. Maybe even exhaust, air pump check valves etc. As Orion said, the best approach is to narrow down the origin.

When it's making the noise, does it do it at idle? If you shut it off and restart it does it still do it? Can you pull the belts and see if it still does it?

**4thGenTA** · 12-20-2009, 07:54 PM

Buy a stethoscope and then you can hear almost exactly where the noise is coming from. Or try cutting a piece of garden hose(about 12 inches) and use that to listen for the noise.

**mxplane123** · 12-22-2009, 03:28 PM

Q- When it's making the noise, does it do it at idle?
A- Yes, but most noticable when reved up and then spools down between 2000 and 1000 RPM.

Q- If you shut it off and restart it does it still do it?
A- Yes, in same manner above.

Q- Can you pull the belts and see if it still does it?
A- Have not tried this...

What still gets me is sometimes it's loud and other times almost un-noticable. Now-- occasionally stops altogether with no ryme or reason...