Just purchased my first C5 the other day. I am not real familiar with the LS engines. Car sounds and runs great. Oil pressure is good. Don't know when oil was last changed, car says it has 46% life left but no idea if it was reset at last oil change.

There are no noticeable noises coming from engine under normal driving conditions regardless of speed. I noticed that when I accelerate hard and take the car up to higher RPMs, it sounds normal until I let off the gas. When I let off the accelerator there is a noise. I guess you'd consider it a ticking or clattering. It is not loud but is there. Once it goes back to lower RPMs there is no odd noises. It'll do it when sitting still after you let off the gas at around probably 2500 or 300 RPMs or higher. Sounds perfect under normal driving. When it does tick it is not very loud, have to listen for it in the cabin to hear it.

It's a 2000 with 58,000 miles on it. Only mods that I know of is a vortex ram air kit installed. So is this normal on these engines? New car for me so getting a little nervous.


One more question:

How smooth does a stock LS1 idle? My LT4 and LT1 both have a smooth idle. This one seems to idle a little more like my C3 with a little bigger cam. Runs great and MPG is right where it should be. Doesn't feel like it is needing a tuneup or anything. Just wondering if this was normal or if someone maybe did a cam swap at one time. When I get the time I'll take it in to a shop and have them look at it.


OK, I just went out and started it and it isn't doing it now. I think it's going to be the oil. It's over 100 degrees here and after driving it for quite a bit is when it did it. When the engine is cooler and the oil pressure is higher I don't hear anything after revving it.

 

To be on the safe side,I would go ahead and change the oil and filter.Personally,I never let mine get below 50% but,that's just me.

 

I know where you are coming from being nervous about it. I have only had mine 3 days now. Also a 2000 with 66K. I get the ticking noise only at cold start up. Pressure is good and it goes away in about a minute or two. I am changing oil and filter tomorrow in hopes that will help
Carl

 

Usually lots of knocking sounds at start, but I don't get any strange noises when running or under accel or dcel.

 

I dont get any at start up and have only had it a few days but now that I am paying more attention to it, I found that it seems to be when the oil has heated up and oil pressure goes down. I'll change the oil and see what happens.


What about the idle on your cars? Stock is it pretty smooth like the LTs?

 

I think what you are hearing at cold startup is called piston slap. This is a common problem with this series engine. Do a search on piston slap and read all about it. You might try running one of the decarbonizing agents through you fuel which may help. I recommend BG 44K or Techron Concentrate.

 

 

Mine idles very smoothly at 700 rpm.

 

Sounds pretty normal to me.

I have had my 02 A4 Coupe for almost 4 years. Had 27000 on it when I bought it and has 116500 on it now. Sounds the same now as when I got it. Piston slap for a minute or less when I start it along with a bit of valve noise that acts the same.

It is my only car and driven every day. It doesn't use any oil unless I beat on (no smoke). Runs as good now as before and still gets 26-27 mpg on the highway.

Phil

 

It's normal.

The sound when you rev and let off the gas is....dig this: The poorly implemented crossover tube in the h-pipe. It sounds like something rattling or clinking. But that's what it is. There was a Chevrolet TSB about it and they were putting x-pipes on (at the dealer no less) to fix it.

These engines have aggressive cam profiles and you'll hear all kinds of ticking and stuff from lifter noise, especially right after startup. The LS1/6 tends to have some piston slap when cold. Chevy says it isn't harmful.

If you have a MN6 transmission, you'll also hear the marbles in a can noise. Also normal.

 

Good I feel better now. You know how it feels when you hear something on a new car

 

58K on the clock is nothing unless it was abused. Just change your oil and filter, check the codes and drive it.