Clanking sound in engine bay

[mr_maxime]

Unfortunately problems keep popping up and I don't have time or money to fix them all. Every now and then when I start the engine I hear a clanking noise slightly forward of the AC condenser. After driving around for a bit there was no longer a noise. I just want to know if this is a serious issue.

https://youtu.be/U9FQCM7XhP4

[jmettee]

Best I can tell from the video, it sounds like a bearing in the pulley system. Most likely 1 of the 2 idler pulleys (or both).....perhaps the bearing in the AC compressor.

Pop the AC on & see if the sound changes significantly with the AC running. If it does, it pretty much points to 1 of those pulley bearings as the load caused by the AC system will change the loading in the bearings, causing the sound to change. To nail it 100%, pull that belt off & see if the sound goes away completely.

[David T]

Really hard to tell. Remove the belts, one at a time, and run the motor. You can run the motor without the A/C belt and you can run the motor for a short time without the water pump and alternator belt. You will know what it is when you don't hear the noise. The 2 idler bearings are a common failure but it could be the water pump or alternator.

[DMCVegas]

Unfortunately problems keep popping up and I don't have time or money to fix them all.

No shame in that at all. Been there, done that.

Probably just the A/C idle pulley bearings. But that noise *does* sound familiar to me... Could be nothing, but...

Question: Have you ever lost your Alternator belt? Like it came off, or especially ever got shredded?

[mr_maxime]

Question: Have you ever lost your Alternator belt? Like it came off, or especially ever got shredded?

Yes, twice. The one on the car when i bought it broke and the oreilly belt burnt off. The DMC belt is still going though.

EDIT:Just went out and started the car, AC was already on and there was no noise. Turned the AC off, still no noise. The AC belt did feel somewhat loose.

[dn010]

While I have a different A/C pulley system on my engine, when my belt was loose the AC compressor would bang while running as it was suddenly stopping and starting with the belt slipping. It wouldn't happen until the A/C was running for a few minutes, possibly when the pressures were built up?

[DMCVegas]

Yes, twice. The one on the car when i bought it broke and the oreilly belt burnt off. The DMC belt is still going though.

EDIT:Just went out and started the car, AC was already on and there was no noise. Turned the AC off, still no noise. The AC belt did feel somewhat loose.

Bearings get noisier as the heat up. So you might not hear this on a cold engine.

With the engine idling, I want you to look straight down at the Alternator and watch the fan blades on it as they spin. Then hit the throttle up to about 5,000 RPMs while watching those blades. Make sure that they don't start flexing too far and are coming into contact with the belt.

[PJ Grady Inc.]

Bearings get noisier as the heat up. So you might not hear this on a cold engine.

With the engine idling, I want you to look straight down at the Alternator and watch the fan blades on it as they spin. Then hit the throttle up to about 5,000 RPMs while watching those blades. Make sure that they don't start flexing too far and are coming into contact with the belt.

That's odd because I usually find bad A/C idler pulley bearings to be noisiest on startup and then dissipating as they warm up. The sound usually approximates the pitch of an old washing machine. The best way to test them is to remove the belt and spin the pulleys by hand. If they sound dry or raspy replace them. Expect China sourced bearings to last no more than 5000 miles. Try to find U.S. (Good luck!) or European sourced bearings if you want reasonable life but be prepared to spend more for quality.
Rob

[Michael]

Just a guess, but a flywheel bolt has backed out and it striking the case. Is it a very loud and hollow sound? Does it speed up with rpm?

[FABombjoy]

Why does the AC need two idlers anyway? Why not just one larger standard v-belt idler on the tensioner?

Seems like reducing speed on the tensioner bearings could help their longevity. This is the only car I've ever had or heard of where idler bearings require routine service :D

[mr_maxime]

Just a guess, but a flywheel bolt has backed out and it striking the case. Is it a very loud and hollow sound? Does it speed up with rpm?

No. It's actually pretty quiet.

[mr_maxime]

Turns out there was nearly no tension on the AC belt. I tightened it up a good deal.

[mr_maxime]

Finally got around to checking and the lower idler pulley bearing is rather crunchy.

[PJ Grady Inc.]

Finally got around to checking and the lower idler pulley bearing is rather crunchy.

"Crunchy" is N.G. I see a belt and bearings in your future.
Rob

[mr_maxime]

I'm not driving it for a whole so I'll try to change them. Not sure I have the tools for the bearing change though.

[mluder]

I'm not driving it for a whole so I'll try to change them. Not sure I have the tools for the bearing change though.

You really only need a pair of cir-clip pliers and a socket big enough to match the outside rim of the bearing... and a hammer.

Cheers
Steve

[PJ Grady Inc.]

You really only need a pair of cir-clip pliers and a socket big enough to match the outside rim of the bearing... and a hammer.

Cheers
Steve
A bench vise works much better than a hammer if you have one.
Rob

[Jonathan]

"Crunchy" is N.G. I see a belt and bearings in your future.
Rob

For some reason I got an image of a "DeLorean Magic 8-Ball" from this.

"Am I going to need to go into my VoD this season?"
"DeLorean Magic 8-Ball says: chances are good!" lol

[mr_maxime]

How do I change the bearing exactly? I've seen the exploded diagram but I'm not clear on the steps and don't want to take apart everything if I don't need to.

[Rich]

How do I change the bearing exactly? I've seen the exploded diagram but I'm not clear on the steps and don't want to take apart everything if I don't need to.

Try this thread for more hints: LINK 1 (http://dmctalk.org/showthread.php?12126-Bearing-replacement-for-A-C-idler-pulley&highlight=bearings)

Also some guidance at the bottom of this A/C Belts article by the late Warren W.: LINK 2 (http://support.delorean.com/kb/a39/belts.aspx)

Finally, a full-page blow-up diagram of the A/C drive belt pieces is on pp N:08:20 in the Workshop Manual.