I just bought an 01SS. car drives great, but I've noticed when I turn my car off after a ride I here a small knocking noise coming from under the car. I dont know if its from the engine or maybe the heat of the exaust(flowmaster) that is causing this. I've hered this same sound on other makes of cars but It kinda trips me out. It almost soung like a small knock on a pan and it does it about every minute after car being shut off and last about for 5 min.then goes away. It also does it when car is cold and I start it up. I am also pumping 87 unleaded fuel can this be a reason??? Is all this normal?Iam I just fraking out? someone help please..

 

sounds like piston slap... go here for more info:
www.pistonslap.com


my SS does it too

 

I listen to a piston slap on that page and it sounded more like a constant raddle. mine doesent do that.

 

"I am also pumping 87 unleaded fuel can this be a reason??? "

Put 93 in it, always, or at least 91 if you can't get 93 in your area.

 

tru...

i never go less than 91, if i can 93 all the time

 

you think that might be the problem?

 

You say is happens when the car is shut off, I would guess its parts cooling down, like an exhaust pipe the metal shrinks, you will hear a clicking sound for about 5 mins after shutting off.

I noticed it more after having LT's installed.

You will hear tapping when starting from cold on start up, this is something different, seems to take a while for oil to get to the top of the heads, after about 2 mins it will go away, mine does this too, but dont know if its beacuse my car is 120,000 miles old or weather they do that from new. I always took it as being normal and I never hit it hard until its warmed up anyway.

 

Check the Y pipe/Intermediate pipe connection with your Flowmaster it might be loose.

 

nothing to worry about then?

 

ahhh.. i wasnt paying attention... sorry, you said "after you turn it OFF"... mine does that too... im guessing its **** cooling down, and metal shrinks as it cools...

trey

 

but I here a the same noise when I first start the car fo the first 5 min when cold.like a small tap or click.