Motor has a Knocking Noise?

[Petar415]

when i start my 96 grand am it has a knocking noise and then when it gets a little warmer u cant hear it that much but u can still hear it a little.........does antone have a clue on what that could be?

[tmanz13]

What you are probably hearing what happens when your engine is still a lilttle cold and the sides of the pistons slap the cylinder walls. This past winter when I first bought my car I did notice a little knocking on cold starts but it just kinda went away. GM says it's normal, so most people agree; but any noise from my engine makes me nervous. I think there is a whole website out there about piston slapping, because a ton of their newer GM cars over the years have been doing it. I'll post the website later if I can find it.

Maybe someone who knows alot more then me could tell ya for sure.. I'm a newbie around here :blush:

[tmanz13]

Hey, a reply to my reply...

here is that website: http://www.pistonslap.com
It's talking more about newer Gm cars though.

But to be totally honest, if you've never noticed that you have been burning a lot of oil, or more then usual; I wouldn't lose any sleep over it.

Take care!

[mikem220153]

Let me see if I can remember this right.... If you hear a knock from the engine during acceleration, it usually indicates a main bearing failing and if you hear a knock from the engine during decceleration, it usually indicates a rod bearing failing. Does either of these coditions exist on your motor. That is 1 possibility. It could also be something in the valve train, such as a bad lifter, or bad rocker. I say this because you stated that the noise lessens after the engine is warmed up. In a valve train problem, it is not unusual for the noise to lessen after the engine has warmed up, because your valve train is then getting better oil flow. In any case, it is something you should have fixed before it causes much more serious problems.

[Marks95GAGT]

This sounds like a bad lifter. The problem is the oil drains from the lifter when the engine isn't running. Then it may take a few minutes for the lift to pump up with oil once you start the engine. This lifter maybe be collapsed when you first start the car. It isn't uncommon, but you may want to try a little higher viscosity oil. I like the 5-50 synthetic. It should quiet it down some.

[mikem220153]

Higher visocity oil is a band aid and not a fix. If it is a bad lifter, you are just postponing the inevitable, and when it fails completely, you will have significantly more damage than just a collapsed lifter. Get it fixed now and avoid a lot more expense later.

[Marks95GAGT]

Old is right...it is just a band aid.....

[Marks95GAGT]

Mine has some lifter noise also, but it quickly goes away. I would fix it, but I am waiting until I finish this supercharged 454 to drop in it.....I think it should just drop right in right? hehehe


:bsmeter:

[tmanz13]

lol... i'd pay to actually see that..

damn little 16yr old and his 13yr old girl friend in a honda del sol crapping their pants when they try to race ya :O

[mikem220153]

I'd like to drop a 454 in mine too, But I can't find a crow bar big enough to lever that sucker in there :D

[TheShiznit]

is a popping sound the same as a knocking sound? cuz a buddy of mine that works at uncle ed's noticed i was a half a quart low at my oil change, and said i had to replace my oil valves, or something near the oil pan, forgot what it was exactly. soooooooo, could teh popping be due to the slight oil cunsumption of late?

[mikem220153]

Was he taking about an oil pressure relief valve?

[TheShiznit]

that coulda been it.....he said i would have to take the whole motor apart to fix it..which i dont believe! but anyway, how are is it to fix those? and would that cause a knockin/popping sound?

[mikem220153]

TheShiznit;

I've done some looking, and I don't think our engines have oil pressure relief valves. I'll check a little further and get back to you.

[TheShiznit]

aight, well, some shit that sounds like that is causing me to leak oil (thank god not too bad)! i dunno what the hell it is tho, but thanks for looking guys

[mikem220153]

TheShiznit;

Here is some more info for you. The oil pressure relief valve (also called the oil pressure regulator) is located in the oil pump in the V6 engine. I am attaching a picture of what it looks like. If this is the item you were told was defective, then you will need to have the oil pump replaced.

Hop this help some

[Marks95GAGT]

How informative. I might have to replace my oil pan gasket due to a small leak. If I do I might put in a new pump. Who knows. Mark

[mikem220153]

Mark;

I would if I was going to do all the work of pulling the pan.

[Marks95GAGT]

sounds like a small but fun project....hehehe...I got my timken bearings/hubs for front, and my steering gear and strut mouns will be in tonght, so wednesday is going to be a busy day I guess.....lol

Mark

[TheShiznit]

hey MIKE,
my oil pressure gauge has been a little aratic (mostly it has been low) lately, so its prolly the oil pressure relief valve. so, if i am going to replace it, do i need to get the valve, spring, and retaining pin, or just the valve?? how hard is it to replace? would i need to drain the oil? etc. i would like to fix this asap, thanx

[mikem220153]

You will have to replace the whole pump. That would actually be easier than just chaning the valve. Later tonight I will post a link to show you how this is done.

[TheShiznit]

so what your saying is, even tho my oil pump may not be bad, it would just be better/easier to change it as to just changing the oil valve? cuz my buddy dint say anything bout the oil pump, he just said, some "valve needs to be fixed, cuz im leakin oil a tiny bit, and to fix it, id need to take the whole motor apart" which i said eariler, i thought was bullshit!

[mikem220153]

If the oil pressure relief valve in the oil pump is sticking open, then consider the codition of the rest of the pump. The valve is part of the pump. In addition to this you can replace the stock pump with a high volume pump. A high volume pump restores the oil pressure and moves more oil through the lubrication system than the stock pump will. Clymer, and Melling both make high volume pumps for your engine. Remember that the oil is the life blood of your motor, wouldn't you want it to be in the best shape possible?

[Marks95GAGT]

I think that one thing that people do not know is that the oil in your engine does more than lubricate your motor and make things slippery and rust resistant. It is also part of the fluid bearings for your car. Your main, rod, and camshafts really aren't bearings in a since that most people think that bearings are. They use oil pressure to provide no-metal to metal contact. It is similar to an air bearing, but instead of air, it is oil. You can do a search on google or yahoo to learn more about fluid bearings, but one thing to remember that if you can maintain a high volume of oil movement, you can maintain the bearings. This might be better for the older vehicles. So if you are going to fix it, spring for the new pump and get a melling. I only used them in my little race engines back in the day.


:bravo: :bravo: :bravo: :bravo: Man I'm beautiful 4 times over....:D

[hmperez]

MY 95 GRAND AM ALSO DOES A KNOCKING SOUND ONCE IN A WHILE WHEN I START THE ENGINE ONLY, LIKE A BIG KNOCK THEN GOES AWAY. SOUNDS LIKE THE BIG KNOCK COMES FROM A LOOSE MOTOR, ANYONE KNOW WHAT IT COULD BE. I RECENTLY PUT A TRANSMISSION MOUNT ON IT CAUSE I THOUGHT THAT WAS WHAT IT WAS SINCE IT LOOKED BAD. BUT IT DIDN'T GO AWAY. ANY SUGGESTIONS ANYONE?

[cocobob]

Hi. I would recommend you perform a vacumm test. It will read alt of the possibilities. Try this site out for testing procedures:
http://users.bigpond.net.au/ergoff/vac1.htm

Cheers