Swapped out pulley I THOUGHT was making chatter, but still have noise. Motor knock?

**McCoyH** · 05-05-2012

Well, using the car lots mechanics stethascope tool, we thought we had the motor knocked or chattering noise diagnosed down to a tentioner pulley. So I swapped the pulley yesterday... didnt fix it. So I took both accessory belts off, then started the car... noise is still there. This tells me it is none of the pulleys or other accessories (we originally thought it could be the waterpump too)...

The noise seems to be coming from the upper part of the motor, or the supercharger but the noise travels so bad its hard to tell...

Any help or suggestions?

thanks

**NR92** · 05-05-2012

get a video of the noise with the belt(s) off

**McCoyH** · 05-05-2012

Well, just getting ready to leave the shop for the weekend.... The noise is the same with belts on or off, so I'll take a video with the belts on so you guys can hear it.

**McCoyH** · 05-05-2012

1999 grand prix gtp motor noise grandprixforums - YouTube

**Dthreap** · 05-05-2012

Does the noise change when going to drive?

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**McCoyH** · 05-05-2012

Yes it goes away while accelerating.

**FordMan77** · 05-06-2012

So you've started it with ALL the belts off (including S/C) and its still present? I just want to be clear this was tried.

After watching the video I noticed a strange color on the inside of the oil fill neck right before you took off the engine cover. Is it just the lighting in the vid or is there a lot of gunk inside that neck? It looked like coolant/oil mix stuck to it to me.

**McCoyH** · 05-06-2012

Yes I tried it with both belts off, noise is still there. as for the oil fill neck I'm not sure I'll have to look at it. This could be a possibilty even though the oil on the dipstick looks clean.

**FordMan77** · 05-06-2012

Alright then, thanks for verifying the belt thing. Have you ever changed the LIM gaskets on this motor?

**Hippo Machine** · 05-06-2012

thats not a knock, it sounds like a bad bearing somewhere, like on a pulley, but you said it wasn't that...

**McCoyH** · 05-06-2012

Originally Posted by FordMan77

Alright then, thanks for verifying the belt thing. Have you ever changed the LIM gaskets on this motor?

No, havent had the car too long. what would that have to do with it? im honestly asking, not being sarcastic... im not a mechanic

Originally Posted by Hippo Machine

thats not a knock, it sounds like a bad bearing somewhere, like on a pulley, but you said it wasn't that...

cant be a pulley, still knocks with both belts off... I wish it was just a pulley cuz I bought one to replace the pulley I thought was making noise.

**FordMan77** · 05-06-2012

No problem... If the LIM gaskets are beginning to fail they allow coolant to mix with the oil which in turn destroys the rod and main bearings and you get a knock that will eventually end up as engine failure. If you take a look at the area where the LIM meets the heads and see a black edge, then you have the factory gaskets that need to be changed. If you see dull aluminum then they have been done already.

The only other thing that I can think of that will tick/knock is a loose rocker arm, cracked flywheel or a bad lifter.

**Swiggles** · 05-07-2012

broken valve spring maybe? it doesnt sound like rod knock. you should do the lim gaskets as preventative maintenance at this point anyways, and use the metal gaskets to replace them. so while you are doing that the top of the motor will be apart and you take the valve covers off and check.

to me it sounds like a valve is hitting the piston because its not closing, leading me to believe its a broken valve spring.

**blueguy** · 05-07-2012

Answer me because I don't like to read...

Any SES lights?

Misfires?

If there is a clattering noise at idle and it goes away...I'm more prone to lean towards a flexplate.

**Swiggles** · 05-07-2012

ah i didnt think if a broken flex plate. it does have that kind of metal sound.

**BillBoost37** · 05-07-2012

Let's not rule out a balancer. The S1 balancers started destroying rubber after about 10 years.

**67goat** · 05-07-2012

As others mentioned, also check the flexplate. Pull the rocker covers off and you'd pretty quickly be able to see if you have a broken valve spring. Rotate engine by hand to see if all 12 valves have same lift (to check for other valve train issues such as rounded out cam or broken lifter).
How is the oil pressure? Try attaching a mechanical gauge as the factory electrical one is not as sensitive to variations. If it is not steady, you likely are facing a spun bearing. To confirm, try pulling off the spark plug wires from the cylinder where it sounds the noise if coming from. If the noise level is reduced, you definitely have a spun rod bearing in that cylinder.

**McCoyH** · 05-07-2012

Ok thank you guys so much. I will hook up the scanner tomorrow at work and check the SES light (I dont think I've ever owned a car without it on all the time so I didnt even think to check the codes, lol I know dumb move) and I try all of the things you guys mentioned.

Thank you guys a ton!!

**McCoyH** · 05-07-2012

Hey, just did a quick search on flex plates and found a help thread on a forum about where I guy said his car rides around on the road at 3000 RPMs and has no power and also makes a "ticking or knocking" noise like mine. Mine also has no power and cruises around at about 2500 RPM... Could this be my problem? I thought my new (used) tranny was just crap and I had a motor knock, but could I just have a bad flex plate and it's causing both problems? If so I will be so relieved!! I'm going to my to run out to my car real quick and see if the noise is louder under the car....

**McCoyH** · 05-07-2012

Sorry for the triple post. I just went out and listened to it... Like I said I'm no mechanic, but it's a little bit louder under the car and I can also hear a rattling / clanking noise like something is loose... Sweet, can't wait to check it out and hopefull get the problems fixed.