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Old Sep 28, 2015 | 06:34 PM
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Default A/C issues

Just want some second opinions on what I believe to be a bad compressor.

Drove the Z today for the first time during the day since about a week, noticed A/C wasn't cooling very much at all below ambient temperature. Hooked up set of gauges, with car off the high and low side pressures are ~125-130. With AC compressor ON (can visibly see and hear AC clutch engage), low side drops to ~110 psi, high side goes to ~150 psi. This is at 90 degree ambient temperature. AC was working last time I drove the car. I recall now that I had been thinking once a few weeks ago that it wasn't cooling as well as it use to (had to keep it on recirculation mode to stay comfortably cool), but being close to 100 degrees outside, I just figured it was the heat. Other than that, only other issue I ever had was that the evaporator would ice over after about 1.5 hrs of constant AC use (like on long road trips). I had checked the low side pressure when I initially noticed the icing issue a couple years ago and it was within spec for the ambient temperature.

So, I'm thinking this is just a compressor that's slowly been going downhill. But I'd like some second opinions before I order a new compressor/drier. Car is an 02 with ~125K, no signs that the A/C has been serviced before.
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Old Sep 28, 2015 | 06:42 PM
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Does your car have LT headers ??
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Old Sep 28, 2015 | 06:42 PM
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Originally Posted by tblu92
Does your car have LT headers ??
Yes. Why?

edit - I've had LTs for 4 years now.

Last edited by onspeed; Sep 28, 2015 at 06:47 PM.
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Old Sep 28, 2015 | 06:51 PM
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OK it is a very common issues with LT's On the Passenger side--one of the exhaust tubes actually touches the A/C line or is extremely close----The easiest fix that almost everyone does---is to bend the soft aluminum A/C line away from the exhaust tube---as far away as you can---- then wrap the A/C line with some sort of automotive heat insulation-- Be gentle as you don't want to force it or break it----
On my car it actualyl was touching the A/C line--I bent it away about 1" and wrapped it and my A/C worked good again----
This may not be your issue---but regardless check it and make sure you have the clearance--- The HOT exhaust heats up the Freon in the line and your A/C will not work
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Old Sep 28, 2015 | 06:58 PM
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Lines aren't touching, and already insulated.

4 years and ~45,000 miles with the LTs
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Old Sep 28, 2015 | 09:45 PM
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Originally Posted by onspeed
With AC compressor ON (can visibly see and hear AC clutch engage), low side drops to ~110 psi, high side goes to ~150 psi. This is at 90 degree ambient temperature.
Sounds like it is low on R134a. You may have a slow leak in the system also.
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Old Sep 28, 2015 | 10:01 PM
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Originally Posted by pjensen
Sounds like it is low on R134a. You may have a slow leak in the system also.
Wouldn't low side pressure be very low if its low on freon and the compressor is engaging? It's not cycling on/off like I'm use to seeing with low freon conditions.

What are the chances it's a bad orifice tube?

Last edited by onspeed; Sep 28, 2015 at 10:06 PM.
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Old Sep 29, 2015 | 12:21 AM
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Usually on a C5 the passenger side will be cold and the drivers side only slightly cool if the system is low on r134. As it drops lower the compressor will not engage and you get no cooling. Pull the codes using the dic and see if you have any actuator codes. Most scanners will not show these codes so use the dic.
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Old Sep 29, 2015 | 11:05 AM
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Pulled the orifice tube, small amount of metal shavings on it. Going to order new compressor/drier/orifice from rockauto, thinking I can get away with using the same condenser. Probably need to flush the system too I guess. here's what it looked like:

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Old Sep 29, 2015 | 12:09 PM
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So, where do you think the METAL shavings came from?
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Old Sep 29, 2015 | 12:58 PM
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With AC compressor ON (can visibly see and hear AC clutch engage), low side drops to ~110 psi, high side goes to ~150 psi.. With those pressures the compressor is done hence
the metal in the system. Flush it good or you may end up needing another compressor
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Old Sep 29, 2015 | 02:34 PM
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Originally Posted by pjensen
Sounds like it is low on R134a. You may have a slow leak in the system also.
Nope.

Originally Posted by BigGun
Usually on a C5 the passenger side will be cold and the drivers side only slightly cool if the system is low on r134. As it drops lower the compressor will not engage and you get no cooling. Pull the codes using the dic and see if you have any actuator codes. Most scanners will not show these codes so use the dic.
Nope.

Originally Posted by 73Corvette
So, where do you think the METAL shavings came from?
Yep. Ended up ordering condenser as well, cheap enough from rockauto. That said, in the past I usually see a LOT more shavings on the orifice tube from a truly grenaded compressor, and then I have trouble flushing the condenser adequately.

Originally Posted by Smoken1
With AC compressor ON (can visibly see and hear AC clutch engage), low side drops to ~110 psi, high side goes to ~150 psi.. With those pressures the compressor is done hence
the metal in the system. Flush it good or you may end up needing another compressor
Yep, thanks. Just wanted some confirmation on what I was thinking.

Last edited by onspeed; Sep 29, 2015 at 02:54 PM.
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