Engine Knock

[mrgmguy]

i have 99 buick century aswell as a 2000 both cars knock when cold and on first start up but it goes away when at normal operating temp, iv heard that these cars are fitted with loose fitting piston thats why it knocks when cold

Topic

[dreamer2355]

Are you sure its not valve train noise rather than knocking as an engine knock would be consistent in most cases.

[EricTheCarGuy]

That’s possible GM build quality is not what it used to be. The first thing I would check is that you are using the correct oil for your engine and that it’s filled to the proper level. Don’t use synthetics as they can actually cause the engine to make more noise and cause leaks. The real question is where is the noise coming from? Find out that and you will have a better idea of what the cause is, here is a video for you.

http://www.youtube.com/watch?v=6mpNRJ7m-c8

[BAXMAN68]

If your cars have the 3.1 or 3.4 (not the dohc) you are right about the pistons. They are not loose fitting, they virtually have no skirt so they slap around inside the cylinder bore. GM’s answer to that was to add a patch of teflon to the thrust side of the piston, which wears off after time and you still have the same situation. I’ve replaced God knows how many pistons under warranty for this exact concern. It is not detrimental to the engine, just an annoyance. But, like the previous posts stated, best to make sure the source of your noise

[dreamer2355]

Quoted From EricTheCarGuy:

That’s possible GM build quality is not what it used to be. The first thing I would check is that you are using the correct oil for your engine and that it’s filled to the proper level. Don’t use synthetics as they can actually cause the engine to make more noise and cause leaks. The real question is where is the noise coming from? Find out that and you will have a better idea of what the cause is, here is a video for you.

http://www.youtube.com/watch?v=6mpNRJ7m-c8

The beginning of this video still makes me laugh!

[spelunkerd]

my chev truck has made squeaky noise in the cold for the last decade. I always assumed it was noisy lifters, but since it didn’t cause other problems and it goes away in the spring I never investigated it further.

[Author]

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