Does it sound like a bad AC compressor?

[PandaBear]

95 Corolla US build, 236k miles, I'd imagine it has a Denso 10PA15C compressor.

It does not make any noise when the AC is not turned on (quiet when AC is off), but when it is on (clutch engaged), it makes low speed howling like noise and I do hear some sort of "spraying" like sound (likely the refrigerant changing phase in the expander).

The system is ice cold but I do see some dark residue on the "belly" of the compressor. 10 years and around 70k miles ago I got into an accident that bent the condenser and it rubbed against the radiator. Didn't realize it at the time and eventually it rubbed into a leak. I replaced the condenser and have a mobile AC guy vacuumed and charged the system.


So do you think it is just normal wear and tear / aging of the system or do you think it is leaking? Should I be concerned about it if it is cold but loud (old car howling, not new car quiet, but not banging or knocking loud either)? I want to drive the car for another 5 years if possible but in our climate a bad AC is enough to send the car to junkyard just as much as head gasket or bad tranny.

 

[Drew99GT]

FWIW, my 94 makes the same noises, and it gets significantly louder in higher ambient temps. Still blows cold. The "spraying" type noise only last a few minutes and goes away. It's always made these noises in the 15 years I've had mine.

 

[PandaBear]

Originally Posted By: Drew99GT
FWIW, my 94 makes the same noises, and it gets significantly louder in higher ambient temps. Still blows cold. The "spraying" type noise only last a few minutes and goes away. It's always made these noises in the 15 years I've had mine.


You mean it has made the same low speed howling noise for the last 15 years? or the "spraying" noise?

So I guess it is no biggie and I'd just leave it.

 

[Lubener]

Compressors do make some noise. If the system works, I would run it the way it is and if the compressor does fail, I may investigate converting it to 134 at that time with a new compressor.I would question if it is worth the investment on a 95 car with that many miles.

 

[Drew99GT]

Originally Posted By: PandaBear
Originally Posted By: Drew99GT
FWIW, my 94 makes the same noises, and it gets significantly louder in higher ambient temps. Still blows cold. The "spraying" type noise only last a few minutes and goes away. It's always made these noises in the 15 years I've had mine.


You mean it has made the same low speed howling noise for the last 15 years? or the "spraying" noise?

So I guess it is no biggie and I'd just leave it.


It's made both noises for 15 years. It actually sounds like mine is louder. It howls louder with higher rpm in high ambient temps.

 

[HerrStig]

Is there an idler pulley which might not like the extra load?

 

[HerrStig]

Originally Posted By: PandaBear
95 Corolla US build, 236k miles, I'd imagine it has a Denso 10PA15C compressor.

It does not make any noise when the AC is not turned on (quiet when AC is off), but when it is on (clutch engaged), it makes low speed howling like noise and I do hear some sort of "spraying" like sound (likely the refrigerant changing phase in the expander).

The system is ice cold but I do see some dark residue on the "belly" of the compressor. 10 years and around 70k miles ago I got into an accident that bent the condenser and it rubbed against the radiator. Didn't realize it at the time and eventually it rubbed into a leak. I replaced the condenser and have a mobile AC guy vacuumed and charged the system.


So do you think it is just normal wear and tear / aging of the system or do you think it is leaking? Should I be concerned about it if it is cold but loud (old car howling, not new car quiet, but not banging or knocking loud either)? I want to drive the car for another 5 years if possible but in our climate a bad AC is enough to send the car to junkyard just as much as head gasket or bad tranny.
The dark stuff is either a little compressor oil or the carbon front bearing dusting. The Denso will go 300K or better in a New England type climate.

 

[spackard]

dark residue on the belly of the compressor means the oil is leaking out of seals and attracting dust. Reefer usually is leaking out too.

 

[The motor guy]

Originally Posted By: HerrStig
Is there an idler pulley which might not like the extra load?


I've thought about this on my truck cause it makes a squeaky bad bearing metal on metal type noise whenever the ac compressor cycles, but doesn't do it when the ac is off.