I have a 2001 SS and I have noticed that during warm up there is a tapping noise coming from the engine. It's not the ABS system, we have already figured that out.
It goes away when the engine fully warms up.
My knowledge is limited on the subject of new engines, but it kind of sounds like a valve. But a valve would click all the time. I took it to the dealer but they didn't hear anything because the car was already warmed up. I could use some help.

 

That is the famous LS1 engine knock... some say it is a legitimate problem while others (most dealers) say it is normal.

Comes from one of two sources (or a combo of both). One, it is the accessories/drive belts and the idler pulley/tensioner - produces a constant tick-tick-tick noise. Usually goes away as the vehicle warms up. There was a TSB on this issue awhile back, but the sound usually comes back even when the dealer supposedly fixes it.

The second source is piston slap (in a minor way). The pistons in our cars and the cylinder linings of the sleeves are made of different metals (steel vs aluminum) which both heat up at different rates. There is a little slack until both metals heat up properly and the piston expands to fill in the cylinder. The slack causes the ticking. GM says it's a good thing because it implies that the two metals aren't rubbing constantly on start up, preserving the engine (important to let the car heat up before goosing it too). Others (some specialist shops) say the real problem is because one of the cylinders (usually #7 or #8 I think) is overbored by GM from the factory (a screw up), allowing too much play with the cylinder (not a good thing). Some people have had the dealers tear apart the car to solve the problem, but I don't know what success they've had.

Whether it is a long run problem or not, I'm not sure. But, it's likely either one of the above reasons. My engine does the same thing.



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2000 Pewter SS #C161
SLP Dual-Dual, Bilstein suspension, Eibachs, 21mm/35mm swaybars, GMAF
SLP CAI w/lower plate, !EGR, Direct-Flo, SLP STB, Ported TB, ASP Crank pulley
SLP/AAM Differential cover, SLP 2600, Powershot, MSD wires, NGK's,
BMR Boxed LCAs, BMR PHB, G2 DSL, Heavy Lead Foot...
http://community.webshots.com/user/murlynd

 

I have the same tick, but I just assumed that it was the hydraulic lifters. When my engine ticks, if I rev it up to increase oil pressure, the ticking goes away for a little while at idle until the lifters start to soften up again. I may be wrong, but that is the assumption I made.

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Mark Striemer
'00 T/A WS6
Modest Mods
"Looking to learn"

 

I'm pretty certain that is another valid explanation for the noise - noisy lifters (which is fairly common on GM cars and vans). The hard part is that all three problems do sound so much alike and react the same way.