Clicking/clacking noise in the Engine

[blairj]

I have a problem with my 1998 Grand Prix GT. There is a clacking noise coming from my engine that started happening during a long trip across west Texas (hot, 80mph, loaded down car). When it started, the check engine light came on a started blinking (cylinder misfire), although that went away. The noise is definitely coming from inside the engine, in the back by the firewall, but it's hard to pin down which side (if I stand on the right, it sounds like it's coming from the left and if I stand on the left, it sounds like it's coming from the right).

I thought it might be something in the valve train, since it sounded like it was coming from that area in the engine. So, I dug down in the engine, replaced the lifters, and removed the valves from the cylinder head. All the push rods, rockers, springs, and valves looked fine to me. When I put everything back together (replacing appropriate gaskets), the noise had not changed. I'm at a loss as to what's wrong. Any ideas?

Here is a video of what is going on taken after replacing the lifters. I took off the valve cover, hoping to see something useful. Sorry about the smoke, some oil spattered on the exhaust when I reved the engine.
Pontiac Grand Prix Noise - YouTube

Thank you!

 

[nik12937]

Did you pull the back spark plugs yet? They may be able to give you a better indication of which cylinder is the culprit, and maybe what is happening.

 

[QUICKSILVER462]

Sounds like worn valve guide/guides.

 

[blairj]

Sounds like worn valve guide/guides.

I did have the cylinder head off and noticed that the buildup in the middle cylinder (#4) was a little oily. So it makes sense that there could be something wrong with the guides and seals. How do I go about removing valve guides? Do they just seat into the cylinder head? Can I just use a pair of pliers to pull them out once I remove the springs, keepers, and seals?

I was also thinking that it could be something with the timing chain... possibly the damper. I'll probably try replacing the seals and guides first since that should be an easier job.

 

[BillBoost37]

Guides need to be pressed in by a machine shop and IIRC then checked etc.

 

[blairj]

I was reading some more about possible problems, and I came across the possibility that it is a spun bearing. After watching some videos of people who have this problem and reading descriptions, I starting to think that's what it is.

So, all of you Grand Prix experts, does this sound like it could be a spun bearing? Pontiac Grand Prix Noise - YouTube
If it is, I'm leaning towards driving the car gently until it dies. Any input on whether or not that's a good decision?

Blairj

 

[penright]

I was reading some more about possible problems, and I came across the possibility that it is a spun bearing. After watching some videos of people who have this problem and reading descriptions, I starting to think that's what it is.

So, all of you Grand Prix experts, does this sound like it could be a spun bearing? Pontiac Grand Prix Noise - YouTube
If it is, I'm leaning towards driving the car gently until it dies. Any input on whether or not that's a good decision?

Blairj

Here is my 02. 20130613_061834_zps9adfaa0b.mp4 Video by penright | Photobucket
Do you think they sound the same? Was yours like that with the valve covers on?

I am thinking piston slap. I would think a rod would be more hollow, but the last spun rod bearing I messed with was a 454 olds Cutlass and my hearing was a lot better then (younger). But the rhythm of both of ours seem to be fast, like valve train. My first thought was lifter, but now you that you tried lifters on yours. How many miles (sorry if I missed it somewhere)? Mine is 240,000

 

[blairj]

Here is my 02. 20130613_061834_zps9adfaa0b.mp4 Video by penright | Photobucket
Do you think they sound the same? Was yours like that with the valve covers on?

I am thinking piston slap. I would think a rod would be more hollow, but the last spun rod bearing I messed with was a 454 olds Cutlass and my hearing was a lot better then (younger). But the rhythm of both of ours seem to be fast, like valve train. My first thought was lifter, but now you that you tried lifters on yours. How many miles (sorry if I missed it somewhere)? Mine is 240,000

My car only has 112000 miles on it and sounds the same with and without the valve cover on. Other than the whining noise in your video, your car sounds exactly like my car. After reading about piston slap and listening to various examples on the internet, I'm still inclined to think that my problem is a spun rod bearing. The noise in my car doesn't change with temperature and came on suddenly (I would think that piston slap would develop slowly over time).

Whether it is a spun bearing causing rod knock or piston slap is kind of a moot point, though, since i'm not really willing to rebuild the engine. I'll probably just keep driving it, keeping the rpms low, and hope it holds out until I have the cash for a new car.

 

[penright]

I had another thought, kind of out there though, I have seen before a piece of carbon do that. Of course that was on carburetor/points type cars, but on a new car is that possible? When I was in high school I work as a mechanic, and I remembered this car sounded like it had a nut on top of the piston. It was 35 years ago, if I remember right we sat the back end out the door and pored some automatic transmission fluid down the carburetor. You had to know what you were doing, too much too fast and hydro-static lock a piston and you got a mess. Plus these new cars burn so much cleaner I doubt if that could be it.
Just brought back youthful memories.

 

[Scottydoggs]

try sea foaming it yet?

one guy here's car sounded like it was knocking on deaths door, he sea foamed it, taped it, and the tick slowly went away. on vid no less. never know, its worth 10 bucks to see.