Thread: Engine weird sounds/chugging

Hi everyone! Great community here! I hope you guys can help me with a problem I'm having with my 1999 Oldsmobile Eighty Eight LS. I understand it's not a Grand Prix, but it's close enough!

When you start the car, you can hear, coming from the driver side under the hood, a weird rattling sound. It sounds like a metal ball being shaken in a metal can. More specifically, it sounds like it's coming around the area where the EGR valve is, but I can't be sure. The sound does NOT go away if the car is warmed up or cooled down. It remains constant when the car is turned on. I was thinking a ball bearing or something?

Anyhow, I posted this on some other forums about a month ago, and some guys recommended to me to check under the valve covers for a loose/broken valve springs.

Yesterday, the sound got a whole lot worse and louder. The engine, where it used to be perfectly linear at idle (in both sound and feel), now very clearly chugs. Also, when driving, somewhere in second gear, you can hear some sort of "flapping" coming from the engine bay, and I can't tell where it's coming from. Also, the performance has decreased a tiny bit. While accelerating, you can clearly hear the engine chugging instead of having a linear sound.

I tried pinpointing the sound with a hose, but that doesn't seem to help. I checked the valve springs under the valve covers, and there are no problems. No broken springs, and none of them were loose. I checked all the spark plugs, I replaced the alternator, the transmission fluid (changed from Dex III to Dex IV). The sound got worse instead of better.

Any idea what may be causing this? There's no warnings or CEL. I'm not exactly sure what the heck is causing this. Is it possible that the gasket for the cat converter needs to be changed and is leaking exhaust? Can an engine that needs an oil change make these kinds of sounds? Now I'm starting to read all about things like cracked/loose flex plates, lifters going bad, bearings going bad, and this is really starting to freak me out.

Any help would be much appreciated. Thanks!

Originally Posted by Swash

Welcome! At first glance (read), my guess would be a collapsed lifter. But - you asked "Can an engine that needs an oil change make these kinds of sounds?" - coupled with the fact that it has gotten worse - I'm leaning towards a bearing that is shot. You could be hearing piston slap, but it's hard to tell without hearing it myself. Any way you could post a video?

Thanks - Swash

Yes. Here's a video of how it sounds.

YouTube - noisy car

Update:

I ran 2 tests.

First, I checked the oil pan to see if there were any metal shards in it, which would mean there is a rod bearing that's spun. Absolutely NO metal in it.

Second, I turned the car on, then took off, one by one, each spark plug wire from the coil pack. I would replace each one after I took it off and listening to see if the sound went away.

This did not make any difference at all. The sound remained.

So am I in the clear regarding a spun rod bearing?

i say exhaust leak also checc your egr tube also

Originally Posted by Swash

That sounds like an exhaust leak. Inspect your manifolds for any cracks, etc.

Just FYI - no metal in the pan does not necessarily mean no spun bearing. But I don't think that is your problem.

-Swash

What's the best way to check for an exhaust leak? Do I have to physically take off the exhaust manifold (most likely rear) and check them for cracks?

Originally Posted by rharper33

i say exhaust leak also checc your egr tube also

I checked the EGR tube and could not see any cracks.

inspect before you remove the rear manifold but truth be known i would be inspecting the egr tube my self these are known to break plus it the logical first step

Update:

I took it to the mechanic. As soon as he heard it, he said "harmonic balancer". He just so happened to have another car in the bay which was throwing a rod, and it sounded NOTHING like my car. Now I see what you guys are talking about a rod bearing going bad; the way it sounded was atrocious.

The mechanic then hooked up the OBD scanner, and there are no error codes; all readings came out normal. I asked him specifically about the oil pressure readings, and he said they all checked out normal (no dropping oil pressure).

He said 2 possibilities: crank position sensor (which I don't think, because the car has no problem with starting or anything like that), or the harmonic balancer.

What do you guys think?

Yet another update:

Ok guys, here's an update.

Sorry I had to do it at night, I have no garage and no other time to do it other than when I get home from work. So here goes:

I drained the oil and took off the oil pan, gasket, and exposed the pistons/rods from below. Inside the oil pan was no debris. There were a few tiny metallic flakes, which I believe came from the drain plug. You guys would know better than I would. But these metallic flakes were few and far between. Please note that the picture is slightly exaggerated (cell phone cam), and whoever installed the oil pan gasket last caked sealant ALL AROUND the gasket, so a lot of that fell in while I was trying to get it out; you can see that in the leftover oil in the oil pan.

http://img269.imageshack.us/img269/2323/0717090017.jpg

I could not discern any scoring. I grabbed the end of each piston rod to check for play; EACH ONE OF THEM (where I'm pointing) have a tiny bit of play, depending on what the position of the rod is. If the piston is up in the cylinder, there is almost no play. If the piston is down, there is a tiny bit of play. All of them, all 6 of them are like this. Is this normal?

Imageshack - 2008buickenclave1st.jpg

I don't know about rod bearings, because I couldn't see them. I think they were under these "caps", covered with 2 bolts; either way, I could not get these caps off.

So I installed a new gasket, put it all back together, took some photos and some videos, and here I am.

I leave it to you guys to have a look at these pictures and tell me if you see anything amiss.

Imageshack - 0716092359
Imageshack - 0717090000
Imageshack - 0717090009
Imageshack - 0717090010
Imageshack - 0717090011
Imageshack - 0717090013


I fired up the car. Here is a video of the car when the engine is cool. As you can see, it's completely silent; exactly how I want it to be. After a few minutes of warming up is when the chugging starts.

YouTube - 07 17 09 0244

Any input after this would be great. Also, you guys are much help; thanks for putting up with me; I'm learning as I go along.

Update:

Got the harmonic balancer, and took it to the mechanic to install. At the last minute, he said it would not be worth it to install, because the harmonic balancer is not the problem; the issue is the TIMING CHAIN. He said it probably got too loose or something, and that I should change that as well as the timing chain tensioner.

Does this sound accurate now?

Does anyone have a write-up on what I need to buy and how to install the new timing chain? Part/procedure recommendation would be very helpful.

Thanks for your help!

I bought a camshaft bolt, as well as the harmonic balancer bolt. Will I need these to do the job (since they are TTY)? I just received the timing parts.

Thanks!

Update:

Changed the timing chain, following instructions completely to the letter. Dotted all the i's and crossed all the t's.

It's still doing the same thing. The timing chain change made no difference at all.

I took it to another local mechanic (Rising Sun Motors) and had them look at it while they did the CASE relearn for me. They had their two most senior technicians look at my car. What are the possibilities they came up with?

1. The oil pan has a slight dent in it. This is causing the oil pickup gears to resonate throughout the engine.
2. It's definitely a moving part, WITHIN the motor.
3. It could be a piston skirt coming loose, but they quickly shot that down after they asked if I tried unplugging one spark coil at a time while the car was running to see if it made a difference in noise.
4. It can't be lifters, because my idle would be much rougher.
5. It can be rockers, valve springs, or something in the valves?

So here I am now. All this work and suffering, and back to square one.

I really don't want to give this up. It's the only car I have, and I've hit a rough financial patch, which will be MUCH worse if I don't have this car.

Another thought that I have. Could it possibly be the oil pump???

Help a buddy out.

Thanks.