A/C not cooling at all?

Tiny
MANUELNP
  • MEMBER
  • 2013 RENAULT MEGANE
  • 1.5L
  • 2WD
  • MANUAL
  • 256,000 MILES
Hi there,

I’d really appreciate your help with the issue below.

Date: 19 Jul 2025

The vehicle listed above is a Renault Mégane III DCi 2013 (Diesel, manual).

General info and tests performed:

A – I recently did an oil service (oil & oil filter). It was a bit challenging to remove the oil filter, which is located close to the AC system.

B – The AC was working well just before the oil service. However, a while back I had noticed that the cooling performance would sometimes fluctuate (getting weaker, then returning to normal). I’m not sure if it’s just a coincidence that it completely stopped working right after the oil service.

C – I found one of the pressure switches/sensors (see Pic 1), which I believe is the low-pressure one. I disconnected and reconnected it to ensure proper contact, but there was no improvement.

D – I’m not sure where the high-pressure switch/sensor is located. Does anyone know? Should I even be concerned about it at this point?

E – I tried the “bypass test” on the pressure switch/sensor by linking both poles with a wire (see Pic 2). The clutch did not engage, so the condenser didn’t start at all.

F – I still need to check the fuses with a multimeter. Do you think this could be the cause? I’m really hoping it’s just that!

G – I noticed a part (see Pics 3 & 4) on the lower left side of the condenser that’s covered in old oil/fluid. I don’t believe it’s from the recent oil/filter change, as it’s quite far from that area and looks old. Does anyone know what part this is exactly and where the oil might have come from?

I’d greatly appreciate any advice or thoughts on this.

Thank you!
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Sunday, July 20th, 2025 AT 6:59 AM

5 Replies

Tiny
MECHTRIX
  • MECHANIC
  • 382 POSTS
Yep sounds like you're on the right track here a few easy things you can try
Follow the hoses from the ac pump around the engine bay and try to see if anything is disconnected, cracked broken or signs of oil leakage and so on.
Check the fuses and relay.
Also if you pop the hood start the car and look at the ac pump pulley and have someone turn on the ac watch and see if the pully the center portion of the pulley starts turning with the pulley when its turned on if it does that's a good sign it means the pump should be working properly. But if not there's a chance it has a leak and the pressurized gas inside the system escaped making it useless if this the case you'll have to find the leak and repair it there's various rubber o ring seals throughout the system. One way you can check to see if it has a y pressure is just drain a little bit for about one second don't want to lose too much if you here it hiss stop check it at the fill port on the low side line. That's a good start I hope this helps enough for you to find the problem but it might not and might need further assistance let us know. Good luck.
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Sunday, July 20th, 2025 AT 4:40 PM
Tiny
MANUELNP
  • MEMBER
  • 3 POSTS
Hi. Note: Will do and send the feedback asap. Thank you for the prompt response!
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Sunday, July 20th, 2025 AT 6:42 PM
Tiny
MECHTRIX
  • MECHANIC
  • 382 POSTS
No worries good looking out "
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Monday, July 21st, 2025 AT 11:37 AM
Tiny
MANUELNP
  • MEMBER
  • 3 POSTS
I took it to an Auto AC specialist to be sure, as I didn’t have all the necessary testing tools.
He connected his manifold gauge set, started the car with the air conditioning on, and within one minute he said “there’s no pressure in the system.” Based on that, he concluded that I need to replace the compressor.
However, he didn’t check any fuses, relays, or anything else. I also didn’t hear the compressor engage at all.

1-Could he really be sure it’s not just a simple burned fuse or relay, since the compressor didn’t engage? How can he see if there’s pressure in the system if the compressor never kicked in?
2-Could it be something else, like a lack of refrigerant or compressor oil in the system?
3-Please also look at these pictures attached, showing a "part near the condenser that’s dirty with oil". Could that be compressor oil, and could this leak have caused the compressor to become damaged beyond repair? What part is it?
Also see engine bay pic 4. Is this pipe connected to this part that is covefed with oil? What is the name of this pipe?

Thank you for your help!
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Thursday, July 24th, 2025 AT 12:37 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
With the system having no refrigerant this is the problem with the A/C, we must find the leak which could be the compressor. Here is a video to help find the leak to confirm:

https://www.youtube.com/watch?v=yrhWKlQEPWw

The oil leak you are looking at is from the turbo and is normal for a car with this many miles on it. Let me know what the leak detection says.
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Friday, July 25th, 2025 AT 9:18 AM

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