Annoying Rattle

[Targa Me]

Hello Everyone,

Subject: 1984 with a stock 3.2, 320k miles on the clock.

The car has developed an annoying rattle. (Comes from the rear of the car)
The rattle is heard when the car is warmed up. Does not rattle first thing in the morning.

1. Doesn't matter if the clutch is engaged or disengaged.
2. Rattle is not affected by engine rpm.
3. Doesn't matter if the transmission is in gear or not.
4. I can't hear the rattle while driving, meanly because of road noice.
5. Seems to be worse after driving for 15 to 20 minutes.
6. After the car sits for 20 mins, after the 20 min drive, the rattle is barely noticable.
7. Over time, rattle is getting worse.
8. I lifted the car, knocked on parts and pieces with a rubber mallet but everything seems to be ok.
9. Gearbox shifts nicely.

Any ideas ?
Thanks.

[pete3799]

Muffler maybe? Internal baffle loose perhaps.

[Targa Me]

I tried tapping on the muffler and didn't hear anything, but maybe an internal baffle ! I never thought of that.
thanks.

[DRACO A5OG]

Brother Larry,

Can you post a video?

Jim

[Targa Me]

I'll see what I can do.

[sugarwood]

Did you poke around the rear while the engine was running?

[DRACO A5OG]

I believe he stated it only happens at speed.

[Targa Me]

I need to lift the car when its hot and run the car for further Dx.

[tirwin]

Loose chain tensioner?

[DRACO A5OG]

Does it sound like a rattling tin trash can? Which oil are you using?

[sugarwood]

Originally Posted by DRACO A5OG

I believe he stated it only happens at speed.

He said he can't hear the rattle while driving.

[DRACO A5OG]

^^^, oops my bad, damn old eyes

Well that is good news.

[jwakil]

Sounds like catalytic converter. It might have a big chunk broken apart internally so you have a piece or pieces rolling around in there. Eventually the pipe will get clogged and bog the engine down. I had this experience before. Also makes sense that the sound would be affected by the temp.

[Targa Me]

Originally Posted by tirwin

Loose chain tensioner?

I would think that a loose tensioner would make the noise regardless of the engine cold or hot.

My rattle is only when the engine is warmed up.

[Targa Me]

Originally Posted by DRACO A5OG

Does it sound like a rattling tin trash can? Which oil are you using?

I'm using AMSOIL 20w-50.
The rattle is not tinny, more of a dull clunk noise.

[Targa Me]

Originally Posted by jwakil

Sounds like catalytic converter. It might have a big chunk broken apart internally so you have a piece or pieces rolling around in there. Eventually the pipe will get clogged and bog the engine down. I had this experience before. Also makes sense that the sound would be affected by the temp.

This weekend I will remove the muffler and CAT to see if I can hear something loose in them.

[tirwin]

You're probably right. I said that because no one else had and you wouldn't want to drive it if it was a tensioner.

Can you record a video and post it? That might help narrow it down.