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I’ve changed my car (Brazilian GM Classic) oil and after the change the A/C stoped working.

I’ve asked for the car dealearship I’ve changed the oil to check it up.

The diagnostic was that the A/C compressor was damaged, the solution was to change it. They explained to me that this damage may happened in some flood I’ve passed by. The explanation was that with the A/C turned on while passing through the flood, the water may be pulled inside and damaged it.

Does this make any sense? Or its just cheap talk?acgmshareimprove this questionasked May 25 ’16 at 21:06Cristiano Araujo10816add a comment

2 Answers

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AC systems are hermetically sealed, no way for water to intrude the system especially if the system has any charge at all.

It could however damage the electrical part of the compressor (clutch magnet) or other parts of the AC electrical system like relays, wiring or switches.shareimprove this answeranswered May 25 ’16 at 21:42Moab5,984827

  • Yep, they said something about the clutch magnet, but for what I can tell, it was not submerged, I will take a look into the compressor location and see if its reasonable … thanks ! – Cristiano Araujo May 25 ’16 at 22:16
  • You can test the clutch magnet, disconnect the connector from the compressor and apply 12v to the 2 prongs at the compressor, it should click and pull the clutch plate inwards. If you use a voltmeter with 10 amp current measurement you can see what the magnet is drawing, it should be below 10a current draw. magnet winding’s can short out due to age or overheating and will pull too much current, but this usually blows the fuse on the ac circuit. – Moab May 26 ’16 at 23:42 

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It sounds a little odd but….it’s possible

The oil change has nothing to do with the AC compressor. So rule that out as a cause in your mind.

The compressor could get damaged if underwater, it’s possible.

I will say I’ve driven my 4×4 truck through rivers where the water was going over the hood and my engine was almost completely submerged and did not experience any issues.shareimprove this answeranswered May 25 ’16 at 21:14DucatiKiller29.7k12117242

  • Yep, I know oil and AC don’t mix, but someone worked in the motor and this was the only abnormal event with the car in this period of time. – Cristiano Araujo May 25 ’16 at 22:13
  • And I would expect an A/C system from a 4×4 Truck to be ready for flood, my entry level car in the other hand …. In Brazil you must have a 4×4 to drive in rainy days … 🙁 – Cristiano Araujo May 25 ’16 at 22:15
  • 1@CristianoAraujo My AC compressor doesn’t seem any different then AC compressors in small cars. It doesn’t even seem bigger or have special seals. Honestly, I don’t really see how an AC compressor can get water in as it is a sealed system but I can see how it is possible. The fan inside the car could get damaged if it sucks water in from the fresh air intake. Is it possible that is what was replaced rather than compressor? – DucatiKiller May 25 ’16 at 22:21 
  • I really don’t know, but all materials in my car are cheap ( I was low on money at the time, regreting now for not expending more),yours maybe is better. Nevertheless, its strange that with the water only the compressor stop working. Anyway, thanks for your attention ! 😉 – Cristiano Araujo May 25 ’16 at 22:29