Strange Rust-like Dust on AC Pulley? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Moto-Mojo · 03-30-2026, 08:27 AM

I noticed this red/brown dust on the AC compressor and AC belt. AC works fine with no unusual noises. The car is a 2015 2SS RS with all original belts and hoses. Doesn't seem like a degrading, black serpentine belt would create reddish dust?

The engine bay is otherwise pristine and never been driven in the rain...(50K miles)
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0stones0 · 03-30-2026, 08:57 AM

Not sure when AC is running if that pulley might get condensation but, if so, could just be road dust that collected on it. No clue, just thinking out loud.

Moto-Mojo · 03-30-2026, 09:22 AM

Quote:

Originally Posted by 0stones0

Not sure when AC is running if that pulley might get condensation but, if so, could just be road dust that collected on it. No clue, just thinking out loud.

It does seem to be collecting in the cupped area of the pulley facing the front of the car. Guess my under hood isn't as clean as I thought! But...it's not on the harmonic balancer pulley.

1JEWLDSSRS · 03-30-2026, 04:18 PM

Quote:

Originally Posted by Moto-Mojo

It does seem to be collecting in the cupped area of the pulley facing the front of the car. Guess my under hood isn't as clean as I thought! But...it's not on the harmonic balancer pulley.

Wipe it off and see how long it takes it to come back. Could be just condensation dirt/dust collected there as mentioned. I get it all the time.

Moto-Mojo · 03-30-2026, 09:07 PM

Quote:

Originally Posted by 1JEWLDSSRS

Wipe it off and see how long it takes it to come back. Could be just condensation dirt/dust collected there as mentioned. I get it all the time.

Maybe the friction material of the compressor 'clutches?' That might make the most sense.

Tenring · 03-30-2026, 10:05 PM

Guessing a little dust is drawing moisture.
Do another parts show anything similar?

102SS · 03-31-2026, 07:00 AM

Quote:

Originally Posted by Moto-Mojo

Maybe the friction material of the compressor 'clutches?' That might make the most sense.

Thats what I was thinking as thats what fails on them first.

Moto-Mojo · 03-31-2026, 01:36 PM

Quote:

Originally Posted by Tenring

Guessing a little dust is drawing moisture.
Do another parts show anything similar?

No. Just the AC.

1JEWLDSSRS · 03-31-2026, 03:13 PM

Quote:

Originally Posted by Moto-Mojo

Maybe the friction material of the compressor 'clutches?' That might make the most sense.

Yep, that's what I'm thinking too..

03-30-2026, 08:27 AM	#1
Moto-Mojo Fast Cars and Old Guitars Drives: 2015 2SS RS (L99, baby!) Join Date: Apr 2012 Location: N. CA Posts: 4,265	Strange Rust-like Dust on AC Pulley? I noticed this red/brown dust on the AC compressor and AC belt. AC works fine with no unusual noises. The car is a 2015 2SS RS with all original belts and hoses. Doesn't seem like a degrading, black serpentine belt would create reddish dust? The engine bay is otherwise pristine and never been driven in the rain...(50K miles) __________________ “I don’t want to belong to any club that would have me as a member.” - Groucho Marx

03-30-2026, 08:57 AM	#2
0stones0 It don’t come easy. Drives: 2010 2SS RS M6 Join Date: May 2014 Location: WI Posts: 2,642 View My Garage	Not sure when AC is running if that pulley might get condensation but, if so, could just be road dust that collected on it. No clue, just thinking out loud. __________________

03-30-2026, 10:05 PM	#6
Tenring Drives: 2015 SS/RS M6 Commemorative Join Date: Apr 2014 Location: Arizona Posts: 2,269	Guessing a little dust is drawing moisture. Do another parts show anything similar?