2007 impala ac issues

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, JohnHere, Dougflas, HECAT

MelancholyImpala
Posts: 7
Read the full article
Joined: Thu Mar 25, 2021 7:09 pm

2007 impala ac issues

Post by MelancholyImpala »

Brand new to the forum, how's it going everyone? I'll preface this with saying i have done quite a bit of my own mechanic work however ac is something i have never really gained a knowledge base on. I just JUST bought a 2007 impala and for the first week the ac worked great then after that the ac would not kick on, the ac light would blink 6 times or the light would turn on for 5 seconds and off for 5 seconds so on and so forth without the compressor kicking on.

Today I was looking under the hood while my friend pressed the ac button and behold, the compressor kicked on. Following that about 8 seconds later something in the front of the car gave way and a huge cloud of hissing refrigerant erupted from the vehicle. When the cloud settled there was a tiny puddle of green dyed ac oil on the ground under the car.

I have ordered a blacklight and glasses to look for the dye specifically but I suspect in the cloud it was flung everywhere and will be hard to identify exactly where the eruption came from and also what the initial problem was in the first place.

What do you guys think could have happened and what should my next steps be to resolve this?
MelancholyImpala
Posts: 7
Joined: Thu Mar 25, 2021 7:09 pm

Re: 2007 impala ac issues

Post by MelancholyImpala »

are there pressure relief valves on car ac systems?
User avatar
JohnHere
Posts: 329
Joined: Sun May 13, 2018 10:20 am
Location: South Carolina Upstate - USA

Re: 2007 impala ac issues

Post by JohnHere »

Yes, there are pressure-relief valves on mobile vehicle A/C systems that will release refrigerant and oil, as you experienced, under conditions of excessively high system pressures. The blinking light indicates a problem as well. Do you have any record of the A/C system being serviced by the previous owner(s)?
MelancholyImpala
Posts: 7
Joined: Thu Mar 25, 2021 7:09 pm

Re: 2007 impala ac issues

Post by MelancholyImpala »

I don’t have any service records of the ac. From what I have been able to agather the most common fix for the light on these cars is a low refrigerant charge however from the blowoff I would assume it was high.
Al9
Posts: 257
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: 2007 impala ac issues

Post by Al9 »

A combo of a dirty condenser and a worn/malfunctioning condenser fan drive system can do that. Perhaps the weather warmed up after the first week.

By the way that's a CVC compressor and the one on my Euro car has an overpressure valve (a little nut looking thing; that colored dot thing held in place by a circlip is the compressor control valve instead) located upon the compressor's head. On my OEM compressor, that relief valve points towards the ground.

I had a worn fan drive motor and the compressor was really noisy in hot weather and, generally speaking, whenever the condenser warmed up, such as when the thermostat opened and the radiator sitting behind it warmed up (made a loud rpm-following groaning noise with the AC on; i'm sure this noise travelled through the refrigerant pipes to the evaporator), until i got the whole fan assembly replaced. All of this with a fully charged system and a recently fitted aftermarket comp (and the old one had the same exact noise issue). Even experienced clutch cut off on one particularly hot day in addition to the noise, but the relief valve never triggered. Now reliably whisper quiet.
MelancholyImpala
Posts: 7
Joined: Thu Mar 25, 2021 7:09 pm

Re: 2007 impala ac issues

Post by MelancholyImpala »

I have found the high side port and there is still pressure and quite a bit of it inside of the line. Is this a good sign since both the port lines are holding pressure? Maybe i just need a professional vacuum and refill of the system?
User avatar
JohnHere
Posts: 329
Joined: Sun May 13, 2018 10:20 am
Location: South Carolina Upstate - USA

Re: 2007 impala ac issues

Post by JohnHere »

Often, when a HPRV opens for whatever reason, it doesn't re-seat properly and will continue to leak, at least a little. I would replace it at this point given the age of your car.

You'll need to determine why it released in the first place. As suggested earlier, a condensing problem is a primary cause of high pressure. Check for debris build-up on the front of the condenser (dirt partially plugging the fins, bugs, leaves, a plastic bag, etc.), as well as the operation of the condenser fan(s).

If the car spent most of its life in an area in which chemicals are used in winter to melt road ice and/or near the seashore, the spring and piston of the HPRV could have corroded badly enough to fail and release. A low-mounted compressor also contributes to corrosion due to road splash.

Along with the loss of refrigerant, some oil also came out. How much? None of us can know for sure. On recharging the system, you could guess, put in an ounce or two, and hope it's enough. If it's not enough, the risk is oil starvation to the compressor and eventual compressor failure. If it's too much, cooling might be compromised.

The only way to add the precise amount of oil back in is to start with a completely empty system: Drain the compressor, flush all old oil out of the components that can be flushed, replace the rest with new parts, then add the correct amount of oil to the compressor and components, reassemble everything, and evacuate/recharge according to spec.
MelancholyImpala
Posts: 7
Joined: Thu Mar 25, 2021 7:09 pm

Re: 2007 impala ac issues

Post by MelancholyImpala »

this is not a salt area vehicle and I'm under the impression that it was severely overfilled to begin with. I am thinking that it is possible that the safety shutoff that keeps the compressor from kicking on during an overfill scenario is malfunctioning and that may have caused the overpressure in the system, however i could be very wrong in that. With the refill i was going to have a full evacuation, vacuum test, reoil and refill.
User avatar
JohnHere
Posts: 329
Joined: Sun May 13, 2018 10:20 am
Location: South Carolina Upstate - USA

Re: 2007 impala ac issues

Post by JohnHere »

MelancholyImpala wrote: Fri Mar 26, 2021 9:47 am ...I'm under the impression that it was severely overfilled to begin with.
Lacking any service records, an overcharge is another possibility. Who knows what was done to it in the past. Could even have sealer in it, which can clog things up and cause high pressures.
MelancholyImpala wrote: Fri Mar 26, 2021 9:47 amI am thinking that it is possible that the safety shutoff that keeps the compressor from kicking on during an overfill scenario is malfunctioning and that may have caused the overpressure in the system, ...
I'm not sure what kind of HPCO switch your car has, and I don't recommend just throwing parts at a problem. But if the HPCO is relatively inexpensive, you could replace that before having it professionally serviced. I'd still replace the HPRV, too, at the same time. Cheap insurance, I think.
Al9
Posts: 257
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: 2007 impala ac issues

Post by Al9 »

MelancholyImpala wrote: Fri Mar 26, 2021 9:47 am With the refill i was going to have a full evacuation, vacuum test, reoil and refill.
As JohnHere said, ensuring the proper amount of oil is in the system is a way more time consuming process than just hooking a machine to the system. The "reoil" the RRR stations usually do is actually inject the same amount that got recovered together with the refrigerant, as fresh oil of course.

Try to remember if the compressor operated in a somewhat noisy way prior to this event. My experience with a GM CVC comp and a TXV based system so far has been that a noisy compressor alerts to a refrigerant pressures issue. Either too high (not enough condenser cooling; i'm positively sure my car's AC never got overfilled, so i can't tell what really happens when the system gets overfilled) or too low (undercharged; i once had half the nominal refrigerant charge amount inside, and again i had a noisy compressor).
Post Reply