Car knocking at idle (In park, neutral and in gear)

[MBrown]

My car is making loud knocking noises at idle. The RPMs are staying right at 700 and the car isn't over heating. During driving everything is fine. Someone suggesting a rocker arm. What do you think it is? This happens in park neutral and in gear.

Oh yeah I have a 2002 Pontiac Grand Am 2.2L EcoTec with 145k on it.

 

[thedarkwolf]

Does it get worse as the engine warms up or better?

 

[MBrown]

worse

 

[CrackRabbit]

Are you able to tell if it is coming from the top or bottom of the engine, or can you get it down to a point it might be coming from?

 

[MBrown]

Originally posted by: CrackRabbit
Are you able to tell if it is coming from the top or bottom of the engine, or can you get it down to a point it might be coming from?

It seems like its coming from the top.

 

[BlackTigers]

Oil level okay?

 

[Pacfanweb]

Low oil pressure is my first guess.

A rocker should get worse as you rev, but I guess with hydraulic lifters, it's possible they might pump up slightly when revved to take up the slack.

 

[CrackRabbit]

I agree with Pacfanweb. When was the last time you had the oil changed? And what weight and filter did you use?

 

[MBrown]

Originally posted by: CrackRabbit
I agree with Pacfanweb. When was the last time you had the oil changed? And what weight and filter did you use?

about 2 months ago. I took it to one of those Valvoline quick lube places. They used 5w-30. Should I put in some 10w-30? Also I checked my oil yesterday and it wasn't low. Maybe it was just the way the sun was on it so I will check it again this morning.

 

[Pacfanweb]

Originally posted by: MBrown

Originally posted by: CrackRabbit
I agree with Pacfanweb. When was the last time you had the oil changed? And what weight and filter did you use?

about 2 months ago. I took it to one of those Valvoline quick lube places. They used 5w-30. Should I put in some 10w-30? Also I checked my oil yesterday and it wasn't low. Maybe it was just the way the sun was on it so I will check it again this morning.

No difference between 5w and 10w 30. That's not the problem.

 

[funboy6942]

OK, what you have is one or more of three things, slipped oil bearing, rod knock, or wrist pin knock.

Your motor is/has failed I would be 99% on this, and would be planning for the worst soon.

You can check further with a largeish screwdriver and figure out which piston it is thats going by placing the screwdriver on the valve cover, over where each of the pistons would be and put your ear on the end of it, the loudest knocking spot wins

Id also be willing as another check is I bet if you keep it in park, and just slightly bring up the idle you'd find the sweet spot with the rpm's that you can make the knock go away or become very faint.

If it were a rocker arm, it wouldnt be a knock sound, more a loud tick, and it would be all the time no matter if in gear or park, or the rpms for it would have to be a lifter for it to go away if anything other then a idle, and Im not sure or not if you have those in that motor, and again it would be a tick, not a knock for it opens the valve on the top half portion of the motor, that is easy to tell just by listening and would be REALLY loud using the screwdriver trick. If its near the top half of the motor, rocker, but bottom half, worse, and there really is nothing more it can be if its the bottom half to make a knocking sound. But since it goes away under stress my money is on lower half something failed and she about to go boom, stay as far away from high rpm's as you can, and baby the hell out of it, no unneccessary stress till you have the means to fix or get something else, and there is NOTHING on the market in a can, bottle, air, that will fix the problem, it must be taken apart.

 

[funboy6942]

Wait, I forgot one more item that would do as you mention as well, that wouldnt be "as" bad, but it would be very highly unlikly, but it would cause the noises, and how the noises come about, and that would be a cracked flywheel, highly unlikely that it would be it, but it to would make the same kind of noise the same way as yours is doing, and would be cheaper to fix then the other three, you'd just have to take it to a trans shop, something like AA, and they usually have a free inspection, and or even Midas, and they will, and should be able to tell you then for nothing where the knock is actually coming from if not the flywheel.

 

[Durbalanar]

Pretty much sounds like what funboy is saying. Good advice, even though its probably what you were wishing it wasnt. Ive gotten rodknocks on several vehicals before (I tend to collect older vehicals). Its only a matter of time before it gets worse. You can get an auto stethoscope, which works better than a screw driver. They are handy to have around. Its basically a thin hallow tube connected to some ear pieces. You can seriously narrow down where the noise is coming from. Also if diagnosing this yourself. I find sometimes you think the knock is in one place, but until you get down on it with a stethoscope, or screw driver, you really cant tell. Sounds reverberate through the engine, and sometimes without the tool, you simply cant pinpoint it.
good luck

 

[darom]

You mentioned that the noise was heard from the top area. If you have access to the lift, check the noises from below. On mine, one of the torque converter bolts backed out, thus hitting the flywheel. It did it at idle mostly, at highway speeds it was ok. The noise seemed to be coming from the front top engine side. It took me a while to figure that out (I was ready to yank the engine out to have it rebuilt).

 

[entros]

These sound like informed and astute observations towards the problem, and that makes me nervous. I have a 96' Chevy Beretta that has been running like a top since I bought it used about 5-6 years ago, until this weekend. I was actually out of town, but as unbelievable as it may sound, my roomate informed me that the noises all started (which I noticed when I got back) when he pulled a dead rat out of the engine; cooked and crispy like it'd been through the ringer in there for a day or so. The symptons from MBrown sound identical to my problem, but I'm just having a hard time figuring out how pulling a dead rat from the engine could affect something internally in the engine? I checked the air filter, no rat in there. Any ideas? Thanks.

 

[boomerang]

Originally posted by: entros
These sound like informed and astute observations towards the problem, and that makes me nervous. I have a 96' Chevy Beretta that has been running like a top since I bought it used about 5-6 years ago, until this weekend. I was actually out of town, but as unbelievable as it may sound, my roomate informed me that the noises all started (which I noticed when I got back) when he pulled a dead rat out of the engine; cooked and crispy like it'd been through the ringer in there for a day or so. The symptons from MBrown sound identical to my problem, but I'm just having a hard time figuring out how pulling a dead rat from the engine could affect something internally in the engine? I checked the air filter, no rat in there. Any ideas? Thanks.

You should start a new thread.