Engine started rattling at idle, quits with just a tiny bit of throttle

[JSD68]

This is weird, and it has me baffled.

The old girl has been running great, until today.

I went to the Court House to get my Antique plates, and when I came out and started up it was rattling like crazy. I gave it just a little throttle and it quit. It runs good, but that damnable rattle is annoying. I got it home and wiggled around on the idler pulley but no luck there. The belt is running smoothly the best I could tell, no fraying or anything. I kicked on the A/C and it got a bit worse at idle, making me thing it is the Compressor clutch, but the air comes on and blows cold, so I know it is engaging. I'm kinda stumped here. Any of you guys have an idea on what it might be? Thank You.

[Ronnie]

It is most likely the harmonic balancer. It is a common problem. Remove the drive belt and start the engine. If the noise goes away you have found the problem. Look for cracks in the rubber on the front of the balancer. The balancer is made in two metal parts with rubber holding them together that deteriorates over time.

[2seater]

I agree Ronnie has this one nailed. Rattle/knock at idle that goes away with a little rpm is the common symptom.

[JSD68]

It is most likely the harmonic balancer. It is a common problem. Remove the drive belt and start the engine. If the noise goes away you have found the problem. Look for cracks in the rubber on the front of the balancer. The balancer is made in two metal parts with rubber holding them together that deteriorates over time.

 

Thanks Ronnie for the info. I'll check that and keep you guys updated.

[AZ Ron]

I had the same thing happen after I had taken my 88 to a local mechanic for a service that requited a hoist.  They screwed up attaching the dust cover for the flywheel.  I started getting worse and would not go away at all.  I finally jacked it up, crawled under the car and found it hanging by only one bolt.  I put it back on securely and the noise went away. 

Probably the damper though.  I have one for sale here and priced reasonably.

[DAVES89]

I wonder how many cars were junked because people thought the engine was going bad [bearing issue]?