Reset compressor

Tiny
BEASY
  • MEMBER
  • 1997 CADILLAC DEVILLE
  • V8
  • FWD
  • AUTOMATIC
  • 89,000 MILES
How to reset the a/c compressor
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Thursday, September 23rd, 2010 AT 12:31 AM

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Tiny
CADIEMAN
  • MEMBER
The compressor will reset after the system is full of refrigerant herr eis a guide to help you.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Please let us know if you need anything else to get the problem fixed.

Cheers
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Thursday, September 23rd, 2010 AT 1:28 PM
Tiny
MATTBRADY
  • MEMBER
  • 1997 CADILLAC DEVILLE
  • V8
  • 2WD
  • AUTOMATIC
  • 89,000 MILES
Need to know - when you take a car your car in for a/c repairs - is it standard practice to leak test the system before doing any work?

I took my caddy in cause a/c had quit working. Compressor was noisy and had a burnt bearing smell. Clearly there was a problem with compressor and it was changed. Morning after I took car home I heard a soft hiss under the dash and then a soft "pop" and a cloud of freon(?) Come up from the right side of the engine (hood was open to jump car). Took car back and was told I had an evaporator leak.

Called another mechanic who said system should've been leak tested before compressor work was done. Said he always does this as compressor went out for a reason and no sense replacing compressor if there's a bigger problem, etc.

I told my mechanic this and he said he couldn't leak test system with shot compressor. I think he could've - but I don't know.

Short/long - 2 quesitons:

(1) Is it standard practive to leak test a/c systems before doing repairs, and

(2) Can you leak test an a/c system with a shot compressor?
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
Yes and no.

Let me type out a long answer to spell check it, and i'll be right back
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
Generally when you charge a system, and especially when you replace a part.
You "suck it down" , meaning you attach a vacuum pump to the system. And let it sit there.
This does two things,
It helps to remove any moisture, as water will boil at lower temps when it's in a vacuum, think of the reverse of a pressure cooker, where water doesn't boil because it's under pressure.
Second, if there is a big leak you will notice it, and if you leave the system in a state of vacuum with a gauge on it, you can even detect small leaks, if you leave the gauges on it long enough.

Saying that.
Putting the system in a vacuum is very mild pressure (about 32 inHg)
compared to what happens on the high side when the compressor is running (about 250 psi)

So it is completely possible that your car was just fine when it left the shop the first time.
And the failure happened later.
Even sitting with the engine off, a fully charged system has about 75 psi in it.

So.

No

kinda.
You do a vacuum test, (see above)
and a few, and I really mean a few specialty places have nitrogen leak testing equipment.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
MATTBRADY
  • MEMBER
Thanks for feedback. Clarification please?

(1) My mechanic told me when I picked up the car that he'd put a green dye in the freon so he could see leaking with a black light - if I had a leak. He said he thought I might have a leak - since compressor went out and no freon in system when he went to do repairs. He told me to drive the car for a few days and then bring it back it so he could give it a once over for leaks.

(2) The morning after I brought it home I started it and that's when I heard the soft hiss under the dash and then hiss/pop/cloud of freon (?) On right side of engine. Cloud of vapor was not green - so not sure about the green dye claim he made.

(3) Having said all that - I have 4 questions:

(A) If you were given a car with a noisy compressor to fix - would you have evacuated the system/noted leaks and not gone any further until leak situation had been discussed?

(B) Since a/c was blowing cool (not cold) right before it quit and I smelled burned bearings - is it likely that freon leaked out slowly and a/c was able to still blow cool right up to the time the compressor crapped out?

(C) Hissing sound ("soft" sounding - but still noticeable) under the dash never occurred before. The morning after I brought car home was first time I heard. Could the mechanic, while repairing the compressor/charging the system, overcharge the system/pop a seal? Only reason I ask is I never heard the hiss before and his voicing a concern about a system leak/coming back to me telling me for sure evaporator has a leak after I took car back makes me wonder if he did something to cause hiss/leak to occur. Thoughts?

(4) Since Caddy's not worth much - would this be a good time to try CryoSeal?
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
I'll address these two together.
With the system not being very cold, it could have had a slow leak, or the compressor could have been weak.
If you have a very slow leak (as you suggest you may have in B) It is hard to find without using dye.
When you put the dye in the system, the results are not instantaneous, the car has to be driven and the AC has to be used for the dye to circulate in the system. Sometimes for weeks.
So discussing the cost to repair any leak was not an option, because no leak had been proven.
PS, it is a very small amount of dye, you would not have noticed a green vapor.

More likely what happened, your system had a slow leak and was low on freon, or the compressor was weak. The system hasn't had to deal with normal operating pressures for a long time.

Once the system had the correct amount of charge, a weak component finally failed. It happens all the time with pressurized lines, a very weak part fails, you repair that and then the next weakest part fails.

You can try it if you want, but I don't have much faith in snake oil products.

Finally.
By what you have said so far, I feel that Your mechanic didn't do anything wrong and has followed standard operating procedures.
But ultimately, If you don't trust him, then go with your feelings and find a different one. You both will be better off.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
MATTBRADY
  • MEMBER
(1) If you were given a car with a noisy compressor to work on - would you evacuate the lines/put system on a vacuum/note if vacuum held before proceeding to replace compressor?

(2) Since car is now hissing/popping/releasing a cloud of vapor on the driver side of the engine when it runs (compressor is on passenger side) - could it be that the orifice wasn't replaced/is clogged and/or something other than a leak in the evaporator is causing the hiss/pop/vapor under the hood?
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
KRISK2003
  • MEMBER
  • 1997 CADILLAC DEVILLE
  • V8
  • 2WD
  • AUTOMATIC
  • 80,000 MILES
Adding R-134. Compressor will not engage or cycle.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
ED ARMES
  • MEMBER
Are you useing gages to check pressures while you are installing the 134?

1. Could still be under charged and the pressure switch on compresser is not being activated.
2. Could be blown fuse, relay or circuit breaker caused by low system over loading circuits.
3. Is compressor actually locked up or clutch bad?
( Was it working before and you are just topping it off? )
4. Was system opened to air for any reason? ( Open system draws moisture and destroys the integrity of the system. Acccumulator should be changed and system vacumned down before addition of 134.

Best I can do with info I have.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
No.
If the system is holding enough pressure for the compressor to run, then it's going to hold enough vacuum to pass that test.
Or
If a car comes in with a locked up compressor,
9 times out of 10 the seal on the compressor is damaged and would fail a vacuum test.

Is this hissing/popping/releasing a cloud of vapor thing on going?
It should only happen one time, after that the freon has leaked out and it cant do it again.

And could you clarify, in one post you said it was coming from the right side of the car, and now you said it is on the driver's side.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUZZSAW
  • MEMBER
Did it stop working at some point? Why are you adding freon. If codes are present for the ac system it wont work you have to reset them

off and warmer on the heater controls w/ key in the on position. The 3 buttons up by the IP is where you reset them, the buttons you use to get to the alt output, RPMs, cooling temp, etc. It will go to do you want to erase codes when in diag mode
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
MATTBRADY
  • MEMBER
(1) Compressor was making noise - i.E. It was turning but I think innards were shot. May not have been able to test for leaks in this condition?

(2) On the noise/vapor - Hiss/pop/vapor release happened when I started car up morning after I brought it home from mechanic. It happened twice. One hiss/pop/vapor release then a second hiss/softer pop/much smaller release of vapor.

Insofar as the hiss/pop/vapor on driver side when compressor's on passenger side issue goes - any ideas?

P.S. - My bad on using right side. I meant the issue's on the right side of the engine if you're standing in front of the car. Figured it would be better to start talking like a mechanic - i.E. Use driver/passengerr side instead of left/right.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
Sure, he could have tested for leaks, but it would have passed. And I'm going to bet that he knows that.

Was this vapor close to the radiator or back near the fire wall? But right now I cant think of anything on the right side.

We say left and right also, but it's as you are sitting in the car, not standing in front of it.

So the roadside, driver's side and left are all the same,
as is curbside, passenger's side and right.

Now to really mess with your head.
The left side of your engine is pointing towards the front of your car, and the right side of the engine is facing the rear of your car. :)
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
MATTBRADY
  • MEMBER
Thanks for input so far. Need some clarification so gonna ask questions a little different/provide some add'l info along with so I can stop bothering you :)

(1) If someone brought you a car with a noisy compressor and, as you proceeded to evacuate the freon you found no freon in the system - would you assume the system had a leak and leak test the system before you did the compressor replacement as a matter of course?

(2) If after replacing the compressor you sent the car home and your customer came back next day telling you he'd heard a hiss/pop under the hood and saw a puff of vapor come up on the driver side of the engine halfway between the radiator and the firewall - would you suspect there was a problem with the compressor you'd just installed or what?
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
I've answered this question twice already. I'll try a different way of explaining myself as well.

These two facts in your question cannot exist at the same time
"a car with a noisy compressor and, as you proceeded to evacuate the freon you found no freon in the system"
There are sensors on the car that keep the compressor from coming on if it's out of freon.
So if the compressor is coming on, I know the system holds at least some pressure. And a vacuum test would not show any problems.
Now I'll offer you a alternate scenario.
Car comes in.
AC system is empty,
I circumvent the safety switch to see if the compressor will engage.
The compressor makes noise.
I replace the compressor.
Put dye in it.
Charge the system.
Since the compressor was bad, it most likely had a bad main seal as well.

If another leak is found, I would give the customer another estimate.
If no leak is immediately found, I would send it home. Comfortable with the knowledge that the dye will help pinpoint the leak if/when the customer comes back.

I would try to duplicate the problem to determine the failed part.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
CLAUDE LOVE
  • MEMBER
  • 1997 CADILLAC DEVILLE
  • 1.8L
  • V8
  • AUTOMATIC
  • 14,565 MILES
Overheat compressor off fan don'ts work
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
MATTBRADY
  • MEMBER
10-4. But the compressor wasn't running when I took car to shop. A/C had stopped running and I smelt a burned metal smell so I never re-engaged the a/c. I just took car to shop and, with just the engine running - there was noise coming from the compressor and the mechanic said I needed a new compressor.

All I'm asking is this:

Before he yanked the compressor - should he not have evacuated the system and in so doing discovered the leak in the evaporator (which is what he now says I have and what he now says caused the a/c system to lose freon and compressor to fail)?
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
CLAUDE LOVE
  • MEMBER
What can I do to resolve compressor fans over heat problem
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
BUDDYCRAIGG
  • EXPERT
I'm sure he evacuated the system, as it's the law. That is not doing a vacuum test.
Should he have performed a vacuum test?
I would not have.

And further more. From what you have told me, it is my opinion that the evaporator was still in working order when it left the shop.
You witnessed the very moment that it failed the next morning.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)
Tiny
HMAC300
  • EXPERT
What do you mean compressor fans overheat the a/c fan for cooling the car? Check fuses and relays under hood if it's the fan for hvac unit that will be under hood as well if fan doesn't come on then the control system has to be scanned to see what is wrong with it.
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Wednesday, October 3rd, 2018 AT 7:00 PM (Merged)

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