Hi, I have Fabia 1 hatchback, 55 kW, 1.4 16V  and have the following issue with AC:

It was not working at all so i took it to be filled with refrigerant. The guy told me the compressor is not working well so i bought I new one and replaced it along with the expansion valve (I know i should have replaced the dryer but i didnt). I took it to be filled up again and it was working well, blowing cold air. This was monday and it was also working on tuesday in quite hot weather, but then on Wednesday it stopped working again. I checked the engine compartment, and i saw that neither of the cooling fans on the front worked. I tried a bit later and then the smaller fan would turn on but the bigger one didn't and the AC was still not blowing cold air. I unplugged the bigger fan and connected it to a 12V battery and it worked, so now both fans were blowing but the AC was still not working. I though maybe the refrigerant leaked out but today the weather cooled down and i tried it and everything was working. AC was blowing cold air and both fans would turn on (the bigger one occasionally turned off). (also it was not just cold air because the outside air is cold, with the AC on it got much colder).

I though maybe the air blend door was faulty but there seems to be no problem switching between cold and hot air. Well at least now when the weather is colder.

 

Any ideas what could be the issue and how could i fix it

Welcome.

Is it a 2001 Fabia so a Mk1?

Listen for a hissing sound from deep in the dashboard central area when you switch on A/C. That might suggest refrigerant quantity has reduced due to leakage.

You really are just searching in the dark without being able to actually check what the system pressure is doing, both on the suction side(low) and the discharge side(high), these systems are designed to get "critically charged" and so will not tolerate overcharging - especially in hot weather.

 

Checking with a fridge manifold set is best, but checking what the system pressure sensor thinks is going on by using a scan tool like VCDS etc is also useful.

Is it a manual AC or Climatronic?

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11 minutes ago, Ootohere said:

Welcome.

Is it a 2001 Fabia so a Mk1?

Thank you, yes its a Mk1

 

I might invest in a manifold set, they dont seem too expensive, but I dont think I could afford a scan tool (from what i seen, they cost a few hundred euros).

 

I know this is a search in the dark, but i dont know what else could i do. I didnt want to write down the full story unnecessarily, but basically what happened is at first i took the car to a mechanic/shop to have the AC fixed, but the only thing they did was fill it up with refrigerant (but they also said that it already had refrigerant but they still charged me full price). At that time it was working when i left the shop, but by the evening it was not working, and when i went back they coudnt figure out why, and they offered me to fix it by replacing literally everything (witch would have cost almost as much as the car itself lol). So next i took it to a different guy who "sucked" out the refrigerant and he told me that the other shop actually overloaded the system, they were supposed to load 550 grams and it had 625 grams of refrigerant, witch is apparently way too much. After this i changed the compressor and the expansion valve, and i trust that he loaded in the right amount of refrigerant (as he himself seemed trustworthy and also had a pretty high tech looking machine for it).

 

My thinking is that it shouldt be leaking because if it did not leak before, the pipes should be fine, and the only places i touched were the compressor and the expansion valve. When i changed them i changed the o rings too and oiled them too so they should be fine. I also checked them (and the pipes i could see) with an UV light and saw no leaking.

 

If we were to assume that its not leaking and the pressure is right, what else could potentially be causing the problem? Is it it possible its the fault of some relay or something else electrical?

 

Thank you all for the replies and sorry for the messy post, i cant write.

4 minutes ago, Jocko said:

Is it a manual AC or Climatronic?

manual

 

That's a pity. My Climatronic has error codes that tell you if the gas pressure is wrong.

I did just notice i posted this in the wrong category, sorry about that.

1 minute ago, Jocko said:

That's a pity. My Climatronic has error codes that tell you if the gas pressure is wrong.

Well im happy it has AC at all 😀

The fans are wired in parallel with each other, so you should never see just one working unless there is a fault (motor brushes worn or sticking in holder), or a low speed internal resistor failed.

Sorry for my ignorance, but would this resistor be located in this fan control unit?

No, internal to each fan motor, the rectangles shown within the fan schematic symbols above.

Oh i see, thats not bad news, I was planning to replace the bigger fan anyways. As i mentioned before, i tried unplugging the bigger fan and connecting it to a 12v battery. I dont exactly know how it works, but it had 3 pins and i tried to connect it to the battery in various ways, and I could only make is spin on what seemed like the high speed, so I assumed that something is must be wrong with it if the low fan speed is not working.

Okay, well i guess i will replace the fan and see what happens. If its still not going to work i will get a set of manifold gauges.

 

Thanks a lot for the help!🙂