Did mechanic ruin my AC compressor

Maintenance/Repairs
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1

I took my car - 2015 Nissan Altima, 33000 miles, to a licensed AC mechanic last week because I was having cooling issues at idle, not any other times and temperature seemed normal at regular speeds. I called around to several mechanics and they suggested it could be an issue with the fan relay and a friend of mine suggested I take it to his mechanic and get it looked at as my regular mechanic couldn’t get to me for a few weeks. I did and the kid that was there suggested it may be a leak somewhere. He hooked it up to a system and said I was low on refrigerant, saying my model (according to the sticker on the hood) needs 2 lbs (I now know the hood says 1.16 lbs) He wanted to do a flush to see where the leak might be. I’m not a mechanic and I trusted him and he did it, although he never did find a leak, or he didn’t tell me I had one. And then his dad (the licensed hvac mechanic) came in about an hour after this kid had been working on my system, and asked me what the problem was and he even suggested it was the fan relay…but his kid was flushing my system because I had a supposed leak. His dad suggested I come back in the morning to get the fan relay done and I left without a working system because they had drained the refrigerant. The next day I dropped my car off and went to get it 8 hours later and they told me I needed a new compressor. It’s blowing cool-warm at best, albeit consistently because the fan relay needed reconnecting all along and they did do that. I took it to another mechanic to have the system checked out and they told me I had 1.40 lbs of refrigerant in (slightly higher than needed) and that the compressor is not generating enough air flow going out… and that I have a leaking shaft seal.

I’m so frustrated because I did have cool air before but now it’s not and I need a new compressor. Could the mechanic have ruined this?

2

If the evaporator fan is not working when you turn the A/C on, there is a problem with the fan relay.
Take your vehicule somewhere else.

3

It’s too late now, that’s why I’m asking if the first mechanic could’ve created a problem that wasn’t there initially, i.e my compressor is bad now. I took it to the first mechanic with the symptoms of a relay… but his kid decided I was low on refrigerant, which was not true… I did not know that at that time as I trusted a licensed mechanics shop.

4

how does shop #2 know how much freon is in car? you have to suck it out and weigh it. did the shop do that? a tech can tell if a system is overcharged if they read pressures and compare it to pressure/temp chart. a/c rad fan is working. air temp is XX. system pressure is XX. yes high pressure can result from system blockage but how is system blocked on a 2015 era car with all original parts and no history of any a/c service?
so, a/c was working ok at idle but not great? it was better last year as you thought there was a problem since you went to garage. so, it could have been only due to a leak which means you may really have a shaft seal leak. the system works now about the same as last week? which means so-so at idle and ok on the hwy? and no shop will replace shaft seal? vs a new OEM compressor for $700? vs an aftermarket comp for $300?

5

Shop #2 did a pressure read and flushed the system, adding back the required 1.21 lbs (as indicated by whatever manual they go by).
Yes, ac was working fine except at idle when it didn’t seem to maintain temp in cabin and less air flow at idle.
No, the system blows lukewarm now all the time, albeit consistently even at idle - 1st shop said they reconnected fan relay, so it was disconnected somewhere initially - which would’ve explained why the ac wasn’t cooling as well at idle.
I don’t know the history of the car, I just bought it 2 weeks ago and the only issue with the ac from then to now is that it didn’t blow as cool at idle. Now after having it taken to shop #1, it blows lukewarm all the time and the compressor is noisy.
I don’t know if they will just replace the shaft seal, but at this point the compressor does seem bad - as in noisy and not generating enough pressure out, regardless of the shaft seal. I’ve been quoted for an aftermarket compresser.
What i’m wondering is when I went to shop #1 my only complaint was that the car did not generate as much air control at idle and only at idle. My complaint now is that the air is lukewarm at best all the time and airflow is poor all the time. Did shop #1 do something wrong?

6

I could think of several possibilities here regarding the servicing but should probably withhold judgement as I could also see some problems that something may be lost in translation.
Flush to find a leak? I don’t think so.,

The lack of cooling at idle could definitely point to a leaky compressor seal or weak compressor. The car is a bit young to suffer A/C compressor problems but anything can happen.

The correct amount of refrigerant does not mean the system will cool properly as there are other factors involved.

Fan relay? Meaning a relay for the radiator/condenser fans or what?

7

I guess your car is out of the 36 month/36,000 mile warranty. Otherwise you would have taken it to the dealer for this.

8

Car is technically 4 years old (put in service june 2014), so yes, it’s out of warranty

9

Whatever fan kicks on to continue cooling the car at idle - it wasn’t working when I took the car in, it was disconnected or something. When I left shop #1, they did indicate they reconnected the fan.

So you’re saying that the disconnected fan had nothing to do with the car not cooling at idle? And that if shop #1 had simply reconnected the fan, it wouldn’t have made a difference at idle even though the car was cooling fine any other time except idle? And that it’s the leaky compressor seal or weak compressor that would’ve been my only cause for the car not cooling at idle, while it cooled fine at other times?

I guess I just want to know if shop #1 could’ve caused greater damage to my ac unit with all that they did vs. simply reconnecting the fan to begin with instead of the flush and whatever else they may have done.

10

I had a car that got warm at stoplights and fine on the highway. Can you hear the compressor kick on and maybe off? My problem ended up a bad variable resistor for the fan motor. There was enough circulation naturally at highway speeds, but none at low speeds or stopped.

11

Reconnecting the fan should not damage anything. The big question is why it was disconnected.
An inoperative cooling fan can cause the engine to overheat a bit and can cause major problems with the A/C.

An inoperative cooling fan can cause the high side pressure in the A/C system to climb higher than normal. This in turn can affect the A/C temperature out of the dash and especially so at idle and slow speed.

The part I don’t get is this bit about flushing to check for leaks. That is simply not needed.

Another part that causes me concern would be if the flushing removed all or most of the refrigerant oil in the A/C system. That can lead to a noisy compressor followed soon after by a ruined compressor.

12

I don’t know why is was disconnected, I just got the car 2 weeks ago, but the consensus I got when I called around and web searched was that the fan was not operating correctly and that is what my normal mechanic would’ve checked if I’d just waited a few weeks to get it in and I thought that’s what another half way smart mechanic would’ve checked first… The one I went to suggested a leak in my system first and foremost and that’s what he started with, checking for a leak… all the while I’m asking about the fan. Come to find out this kid is not licensed but his dad is and his dad suggested it was a fan issue too, but the kid had already flushed my system and did other things to it but never checked the fan before his dad showed up. When his dad showed up, he had the kid put everything back together and told me to come back in the morning to fix the fan issue… that’s what I did and left it all day and when I returned, the dad insisted I had a bad compressor all along but that he did reconnect the fan that was disconnected and the air flow was consistent after that, just much warmer than it was before I took it in and I could hear the compressor grumbling, something I didn’t hear when I took it to them to begin with.

13

Thanks. It’s too late to determine what was wrong with it initially as now I know the compressor is bad according to shop #2 that I took it to the very next day. Just trying to determine if shop #1 created more problems for my system when it could’ve been the fan issue to begin with.

14

You bought a used car with a poorly operating air conditioner 2 weeks ago. Perhaps that is why it was sold. While possible the shop could have damaged the AC, I would suspect that it was already ruined and now the last person to touch it gets the blame. Any chance you have a warranty from the seller to go back on?

15

The AC is working worse today than when I took it in to shop #1… So yes, I think they did something to my system to cause it to work worse than it did before I took it to them… Like going to a doctor with a mild pain and you go out in excruciating pain… the doctor did something wrong and you’d want to know what it is.

The shop won’t talk to me, they clam up, their stories are inconsistent (for instance dad says he removed the refrigerant before I left the first night, not sure why he just said he knew I was bringing it back the next day to be worked on, whereas his kid says it was full), I couldn’t get a write up of what they did that day - they said they’ll get me one next week (getting their stories straight perhaps?)… They seem extremely shady with this whole thing.

16

I’d report the shop to the EPA, telling them that an uncertified technician worked on your AC system.

Big fines and loss of certification for the shop to work on AC systems.

Tester

2 Likes
17

Good to know and probably going to happen

18

Lack of cooling fan operation can certainly cause the A/C to become less oll at idle or low speeds. Fan operation should be the first check followed by checking system pressures and for leaks.

Tester is also right about consequences.

About 15 years ago a company fleet mechanic in Kansas CIty wrongly serviced an A/C in a company van; although I don’t remember the details. The story said he was being fined 50 grand and facing jail time.

19

If you have a situation where your car’s air conditioner compressor clutch doesn’t engage, try the troubleshooting techniques described here.

Car makers use an electro-magnetic clutch to engage and disengage the air conditioning compressor.

The three components of a car’s air conditioning compressor clutch

When power energizes the clutch coil, the magnetic field pulls the clutch in to engage the compressor shaft. If the clutch doesn’t engage, the air conditioning compressor can’t pump refrigerant. So start your diagnosis by determining if the compressor clutch works.

Turn the air conditioning controls to MAX AC and start the engine. Then look at the front of the compressor clutch. Both the pulley and the clutch should be spinning. If only the pulley is turning, there’s a problem somewhere in the system.

If the clutch doesn’t engage, the problem could be a blown fuse, an open in the wire to the clutch coil, a bad clutch coil, a poor ground, or a low pressure lockout.

In some vehicles the compressor clutch relay is turned on and off by the low pressure switch and the evaporator temperature sensor.

In a computer controlled system, the compressor clutch relay is grounded by the computer.

Disconnect the electrical connector from the clutch coil. Move it away from moving parts so you can safely check for power and ground. With engine running and the AC set to MAX, use a digital voltmeter to check for battery voltage and good ground at the connector.

If you’re not getting battery voltage, check the fuse. If the fuse is good, pull the compressor clutch relay and check for power and ground on the relay control coil terminals in the socket.

Wiring varies by make, model, and year. Some car makers trigger the relay control coil ground through the PCM or ECM. In order for the computer to provide ground, it must receive a good signal from the low pressure switch, high pressure switch, and evaporator temperature sensor.

In other vehicles the power flows through the air conditioning switch to the fuse and from the fuse through the low pressure and evaporator temperature sensor to the clutch coil.

It’s important to note that air conditioning compressors need a constant supply of oil to prevent catastrophic failure. That’s why car makers install a low pressure switch–to prevent the compressor from running if the system is low on refrigerant. DIY recharging kits tell you to recharge through the low pressure port while the compressor is engaged. But if the system is too low on refrigerant, the clutch will never engage. Some DIYers then hotwire the low pressure switch to force the compressor clutch to engage while they recharge. BAD MOVE. At that point you’re running the compressor with little to no oil. You may get it to accept a charge, but you may have already damaged the compressor. NEVER try to bypass the low pressure switch. Doing so will force the compressor to run with inadequate oil and can destroy the compressor.

Theoretically, if an air conditioning system is low enough on refrigerant to disengage the compressor clutch, it’s too low to be recharged with a DIY kit. The leak is large and should be repaired, because there’s probably air and moisture in the system. Moisture reacts with the refrigerant and oil to cause acid and sludge that can destroy the system. Then the system should be fully evacuated to remove all air before recharging.

However, I’m smart enough to know you probably won’t do that.