Just looking for some advice. The last two morning when starting my car to leave for work there is a knocking sound right after the motor turns over. It only last for like 2 or three seconds. Thinking this have something to do with oil delivery maybe? The car has 650mi (mostly freeway from driving to the masters last weekend) and i haven't been driving it hard.

Any ideas on what this is and is anyone else experiencing the same thing?

-Mike

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2008 G8 GT BLACK. #130 OF THE 888.

A lot of GM motors have had a problem with piston slap at startup, that's what this sounds like. GM says there is no problem with those.

First, I'd change the oil (use synthetic!) and use a high quality oil filter. I like K&N's oil filters best, Mobil 1 second.

You might go to the dealership and compare your car to others, to see if it's normal or not. If not, definitely take action with your dealer's service department.

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i have a wierd noise too.i dont think its from the engine but i think rather the suspension.

when i start the car put it in drive, a few seconds after i start moving i hear a clunk noise from the front right of the car. it only happens after i start moving and more often when its a cold start like in the mornings or after 10 hrs of work. does anyone think they know what that is? just so that when i drive 20 miles to my dealer, i dont get there tell them about the noise but cant show them cause the cars not cold..

in my oppinon it seams like its the stability control activating but i dont thing thats how it works..

and with your noise in the engine, i would make sure your oil is full and make sure there is no leaks or loose hoses under the hood.

Nick

I might be wrong but I remember being told to run a new engine on dino oil for the first 5 or 10k miles before you switch to synthetic. This might just be an old gear head myth I'm not sure

Jimmy

I have the same thing, sounds like from the right front where the abs/stability control is, other cars I have had did the same thing, I was told for those cars (not the G8) that this is a "self test" mode and runs when not used for several hours.

I have it as well. If anyone has anymore info on this, please chime in. Other than that, so far so good!

ABS self test will make the sound after the key is turn to the on position without starting the engine. Check if that is where the noise occours. It is normal as teh ABS solenoids go thru a diagnostic self test.

Cold start piston slap is and has been an LS motor normal occourance. Only lasts 2-4 seconds and then never again until overnight, wont happen on a warm engine.

My dealer informed me that it is the ABS system booting up. Happens once a day - which is exactly what I hear. This sounds unrelated to the other noise mentioned in this thread.

What do people, who buy cars that already have synthetic oil installed from the factory do? Do they drain it at 600 with dino and at 3k change back to syn?

If they've got synthetic from the factory then the engine was broken in prior to shipment on an engine dyno.