Car sounds! what is wrong with my engine?

ok so had this problem for a couple of months now, i hear a knocking or clattering sound when the car starts up cold, disapears when started warm or after warm up, i notice the sound get louder and sounds rougher when its really cold out (0-20 F ) and when i accelerate without letting car warm up a bit it sounds really loud. At first thought it might be knocking, however after i listened to it closely it sound more like vavles clattering.

Here are 2 sound clips (sorry for cars passing in background)

mic set on car hood, then after start up moved closer to grill

http://www.yousendit.com/download/MzZGMFhnUzh3TGg1VEE9PQ (http://www.yousendit.com/download/MzZGMFhnUzh3TGg1VEE9PQ)


hood opened and mic set next to engine (sound is hard to hear here, it disapears becuase engine was warm for first start-up) (how does engine sound otherwise?)

http://www.yousendit.com/download/MzZGMFhrQXBVVGw1VEE9PQ (http://www.yousendit.com/download/MzZGMFhrQXBVVGw1VEE9PQ)

first one is best indicator you can clearly hear sound

Thanks, john

Sounds like a valve tick to me. Could also be piston slap.

What car, year, engine?

Sounds like a valve tick to me. Could also be piston slap.

What car, year, engine?


1996 buick century 105,00 miles 3.1 v6

ok so had this problem for a couple of months now, i hear a knocking or clattering sound when the car starts up cold, disapears when started warm or after warm up, i notice the sound get louder and sounds rougher when its really cold out (0-20 F ) and when i accelerate without letting car warm up a bit it sounds really loud.


You have just described classic piston slap sounds

If this has come on relatively suddenly, its possible one piston has a collapsed skirt.
If you are lucky, you can locate the piston, pull the intake, head and oil pan, remove the offending piston, hone the cylinder and pop in a new piston.
You should be able to do all this without removing the engine. I have done just this on a Chevy 2.8 V6 (same engine family as yours) with complete success.

If the cylinder or engine wear is too great, its time for a rebuild.

the "fix" for the GM piston slap is to perform a "motorvac", which many shops can do. Roughly $150. Although I thought that was more of a problem with the new-style V8's such as the 4.8's and 5.3's

Either way, I agree it sounds like a top end noise. Could be valves or pistons slap. Need to narrow it down with a stethoscope

You have just described classic piston slap sounds

If this has come on relatively suddenly, its possible one piston has a collapsed skirt.
If you are lucky, you can locate the piston, pull the intake, head and oil pan, remove the offending piston, hone the cylinder and pop in a new piston.
You should be able to do all this without removing the engine. I have done just this on a Chevy 2.8 V6 (same engine family as yours) with complete success.

If the cylinder or engine wear is too great, its time for a rebuild.


Can a compression check confirm this?

You have just described classic piston slap sounds

If this has come on relatively suddenly, its possible one piston has a collapsed skirt.
If you are lucky, you can locate the piston, pull the intake, head and oil pan, remove the offending piston, hone the cylinder and pop in a new piston.
You should be able to do all this without removing the engine. I have done just this on a Chevy 2.8 V6 (same engine family as yours) with complete success.

If the cylinder or engine wear is too great, its time for a rebuild.


Can a compression check confirm this?

You have just described classic piston slap sounds

If this has come on relatively suddenly, its possible one piston has a collapsed skirt.
If you are lucky, you can locate the piston, pull the intake, head and oil pan, remove the offending piston, hone the cylinder and pop in a new piston.
You should be able to do all this without removing the engine. I have done just this on a Chevy 2.8 V6 (same engine family as yours) with complete success.

If the cylinder or engine wear is too great, its time for a rebuild.


Can a compression check confirm this?