When I start my car sometimes I hear the engine making kind of a knocking sound, and then after I let it warm up a bit, its fine... I was just wondering if this is normal for a cold start, or if there is something wrong with it? Its an LS1 99TransAm and Im running Premium Fuel in it.

 

you should run a search and find the billion topics of the many sounds of an ls1 engine.

but to clarify, its probably piston slap which is justified as being normal according to GM.

i have it and have had it since i bought it with 11k on the dial...car now has 46k on it and has since gone through a cam swap and many bolt on mods, now has nitrous and (knock on wood) still no major engine deficiencies due to this knock.

 

Thanks alot man... Not as worried now lol

 

I've had piston slap every winter since I purchased my car in March of 2000. I made sure that it was documented as having piston slap my last time getting warranty work.

I changed the oil myself for the first time since I bought the car and decided to get an oil sample tested. I should have been changing it myself the whole time to keep an eye on the magnet in the plug. When I took the plug out there was iron particles on the plug and gray material in the first little bit that came out. Here are my results:

 

Sorry about being off topic, but that's a great poster and slogan, BS!

Back on topic, yes LS1's are notorious for piston slap, but it doesn't hurt anything, just annoy you. Of course my engine has never had it, so it's easy for me to say that!

 

have you had any ill effects on the engine due to your findings????

ive personally never noticed any metal on the magnet in my engine and i allways change my own oil for this simple reason...i like to inspect and disect whenever i can. documentation is key...that way if something ever happens they can research back and clearly see that you were concerned with it but GM failed to do anything about it.

 

No obvious ill effects yet. But I'll be changing my own oil and taking samples from now on.