Noisey and chattering 3.8

[Sterling52]

My Buick at around 1000 to 1500 rpm under light load makes this chatter noise which sounds like its in the valve train. It comes in all at once and as soon as it reaches and exact RPM it goes away, it doesn't matter whether its cold or hot. This engine has been doing this for sometime and doesn't effect the performance. Does anyone else have this problem, and have they addressed it? The engine has about 120,000 miles on it.

[RABarrett]

Check the timing chain. These engines are prone to eating the chains, and in some cases, it will bend valves. Ray

[Sterling52]

Originally Posted by RABarrett

Check the timing chain. These engines are prone to eating the chains, and in some cases, it will bend valves. Ray

Thanks for the answer RABarrett. I will probably tear into it and replace the chain and gear very soon. I did hook a timming light to it and watched the damper pulley, usually if the timimg chain is stretched it will move back forth alot, but on this check the damper moved around very little. Looked like normal timing adjustment by the computer.

[Vancouver_TType]

Now you're probably on the right track, and I'm not total car guy, but when I bought my 88 Lesabre it was making a lot of noise. I thought it was the timing chain. So I replaced the original one it had, and all the sensors and crap while I was in there. That wasn't it. I figured it must be the bearings in something, so I replaced the waterpump and alternator. Still sounds terrible. Checked the rockers...Fine. Checked the P/S pump...Fine. Was it coming from the old stock cat?? Lets replace the whole exhaust system. Still chattering. Know what it was the whole time? The big fat stretched chain inside the transmission. I'm not too bitter because I wanted to repalce all that stuff anyhow, and the car sounds alot better with a Magnaflow cat and Flowmaster muffler...and it doesn't sound like its got no oil anymore. Funny thing is the sound bounces off everything in the engine bay, so I couldn't zone in on it, even with a hose in my ear!!!

[Sterling52]

Originally Posted by Vancouver_TType

Now you're probably on the right track, and I'm not total car guy, but when I bought my 88 Lesabre it was making a lot of noise. I thought it was the timing chain. So I replaced the original one it had, and all the sensors and crap while I was in there. That wasn't it. I figured it must be the bearings in something, so I replaced the waterpump and alternator. Still sounds terrible. Checked the rockers...Fine. Checked the P/S pump...Fine. Was it coming from the old stock cat?? Lets replace the whole exhaust system. Still chattering. Know what it was the whole time? The big fat stretched chain inside the transmission. I'm not too bitter because I wanted to repalce all that stuff anyhow, and the car sounds alot better with a Magnaflow cat and Flowmaster muffler...and it doesn't sound like its got no oil anymore. Funny thing is the sound bounces off everything in the engine bay, so I couldn't zone in on it, even with a hose in my ear!!!

Thanks a lot Vancouver, my car sounds just like you described yours was doing. That noise is in that engine compartment and you just can't tell where its coming from. I'm sorry you spent all that money on other parts you didn't really need but it will save me several dollars and a lot of time looking for the problem, by you telling me this. Thanks again I appreciate It.

[LeSabre85]

My car does the same thing...i thought it was the driveshaft...nope...i checked the bearings in the accessopry dirve...nope...if its the timing chain, ill give it a shot, but the car only has 52000 miles on it and was driven on the highway for most of that time. i highly doubt its the timing chain. try the heat shield, because it cuz it can make the same noise as a timing chain

[Racincc85]

vancouver, did you replace the chain in the transmission yourself? I've got the same noise on mine, it annoys the heck outta me and i'm cheap and would like to fix it myself.

[Racincc85]

I've got the exact same noise on my 90 lesabre. vancouver, did you replace the chain yourself? If you did, was it difficult/expensive to do? this noise is driving me nuts and i want to fix it asap. Thnx

[Sterling52]

No I haven't done anything to it, still driving it. Its a chattering noise I only hear when the engine is running around 1000 to 1500 rpm, either in Neutral or light load. When I listen to it, sounds like its in the exhaust headers and I also have heard other cars during these model years sound the same. I'm sorry, I know this is not the answer your looking for.

[Sterling52]

Originally Posted by Sterling52

No I haven't done anything to it, still driving it. Its a chattering noise I only hear when the engine is running around 1000 to 1500 rpm, either in Neutral or light load. When I listen to it, sounds like its in the exhaust headers and I also have heard other cars during these model years sound the same. I'm sorry, I know this is not the answer your looking for.

Well my problem finally showed its true colors a few days ago. It developed a severe knock in the timing gear area. I'll be taking it apart in a few days and see how much damage is done.

[_J_]

I've heard a similar sound from my 2001. I only hear it at low rpm under load, like going up a moderate hill. Its when the engine lugs every so slightly going up just the right slope (like going 50mph in 4th). If its real steep, the transmission down shifts and there is no noise.

I thought it was the heat shields. I had a muffler shop check it out and they said it was the flex tube type of heatshield that goes from the engine down to the exhaust pipe. They said there's no clamps, so it can't be tightened.

I will keep the timing chain in mind however.

[Sterling52]

Originally Posted by _J_

I've heard a similar sound from my 2001. I only hear it at low rpm under load, like going up a moderate hill. Its when the engine lugs every so slightly going up just the right slope (like going 50mph in 4th). If its real steep, the transmission down shifts and there is no noise.

I thought it was the heat shields. I had a muffler shop check it out and they said it was the flex tube type of heatshield that goes from the engine down to the exhaust pipe. They said there's no clamps, so it can't be tightened.

I will keep the timing chain in mind however.

In a previous note above, my car had starting knocking. So I pulled the Harmonic balancer off and it was the source of the knock the rubber had failed letting the balancer knock. So I purchased a new one. Since I was in it that far I remove the timing cover to find that a small block they call a damper had just about been sawed into by the timing chain, the chain and gears look good so did the oil pump, but I did put a new kit in the pump which contained two gears,one inside of the other and a new relief plunger and spring. And of course a new timing chain and gears with the new damper which keeps the chain tight with a spring. The problem with the chattering and noisey is still their, sounds like its in the valve train. Its the loudest at between 1000 to 2000 rpm but very light at idle which is about 650 rpm, I guess with a enough money and time i will find and fix it. The car runs great drives like new.
As for your car. How many miles does your 2001 have on it? Unless it has a lot of miles on it I don't see any problem with timing chain. Mine would kick back when I tried to start it cold in the mornings, but since I replaced that damper and chain that fixed that. As for your knock at 50 mph, the exhaust may be it but there could be other things like a water pump etc. Once I had a pickup that got a rock caught between the frame and exhaust pipe and it made a noise like a u-joint was out of it, needless to say I spent alot time and money trying to figure this one out.

[rustbucket]

I also had a damper make noise. Examining the back of it, the support arms were fairly close together (1/4"-1/2") and I saw some shiny metal where it appeared they could touch. I put a tyrap around the arm in that area and reinstalled and the noise was better. I went and bought a new damper ($218) and problem cured.

[Sterling52]

Originally Posted by rustbucket

I also had a damper make noise. Examining the back of it, the support arms were fairly close together (1/4"-1/2") and I saw some shiny metal where it appeared they could touch. I put a tyrap around the arm in that area and reinstalled and the noise was better. I went and bought a new damper ($218) and problem cured.

I never thought about putting a type wrap around it too stop the knocking, but until I got the balancer off and see where it had been hitting at. I didn't really realize it was the damper. I got mine at O'reilly auto parts for $89.00 plus tax.

[JLKINSER1970]

I just had my heads redone om my 98 Buicl LeSabre because of a misfire. Before I took the heads off, mine made a chattering and was noisey. Got the heads back from the machine shop and put the engine all back together. The chatter and noise is gone.