Air Con Gas Pressure Sensor Leaking

[RUM4MO]

Well it looks like I've just joined the "my air con pressure sensor is leaking" club! My oldest daughter has just returned to UK and I've sold her back her old car, a late 2009 Ibiza, so far so good. Today has been unusually warm./hot so she, who is more used to a steady +30C from her time in KL, was finding the car a bit too warm, so switched on the Air Con, hissing noises and not too much cooling - oh bother! Now that I've had a look under the bonnet I've discovered that the gas pipe with the pressure sensor on it is a bit oily and dirty near where the pressure sensor is located - strange that I have not noticed that in the past, maybe I conveniently ignored it was I don't need to use the Air Con!

 

[.-Sam6J-.]

Well it looks like I've just joined the "my air con pressure sensor is leaking" club! My oldest daughter has just returned to UK and I've sold her back her old car, a late 2009 Ibiza, so far so good. Today has been unusually warm./hot so she, who is more used to a steady +30C from her time in KL, was finding the car a bit too warm, so switched on the Air Con, hissing noises and not too much cooling - oh bother! Now that I've had a look under the bonnet I've discovered that the gas pipe with the pressure sensor on it is a bit oily and dirty near where the pressure sensor is located - strange that I have not noticed that in the past, maybe I conveniently ignored it was I don't need to use the Air Con!

I had a hissing noise and hardly any air coming out from my vents and it turned out my pollen filter was not together properly, one of the clips had come off. Sounds stupid but happend to me.

 

[RUM4MO]

I had a hissing noise and hardly any air coming out from my vents and it turned out my pollen filter was not together properly, one of the clips had come off. Sounds stupid but happend to me.

Thanks, but no, that area of the system is okay, the hissing noise is coming from the lack of gas expanding into the evaporator which is inside the airbox inside the car, with the correct load of refrigerant in the system, and everything else being good, there should be no hissing noise - well not enough for you to hear inside the car.

 

[RUM4MO]

Well Mike got a new air con sensor to me very quickly and it has now been fitted along with a new O-ring seal - suitably wetted with Krytec to lubricate the seal, original sensor p/n was 1K0 959 126A, new sensor is 5K0 959 126, so hopefully this one will stay intact for a while longer. Now all I have to do is wait for the return of warm dry weather and I'll get my fridge gauges onto that system and load in enough R134A to stop the hissing and that should return the air con to chilling down the incoming air.

 

[Steve221]

I had a hissing noise and hardly any air coming out from my vents and it turned out my pollen filter was not together properly, one of the clips had come off. Sounds stupid but happend to me.

I've had air con gas issues that the dealer refused to aknowledge and this summer I've noticed this strange hissing noise from behind the dash when the air con is on. Hopefully this is the issue.

Cheers for the info.

 

[RUM4MO]

I'd think, that if the hissing is only happening when you run with AC on, then either you have a low gas charge in that system, or some form of blockage limiting the delivery of refrigerant to the evaporator - and not a loose pollen filter issue.

 

[RUM4MO]

Oh well that quick and easy fix does not look to be the complete story. I cleaned up all other possible leak sites before loading in R134a to complete this job, and discovered that the compressor body gasket is leaking slightly and as I'm an F-Gas card holder, that means that I'll have to sort out that leak, which means replacing the compressor!

Has anyone used ECP to buy a Denso compressor, the reason that I ask is that they show a 120ccm Denso whereas the one fitted to that, according to Denso E-cat is, a 140ccm, so the ECP will be a slightly lower displacement, ie only 85% - but maybe that is good enough for a Northern UK summer?

 

[RUM4MO]

Well currently I am revising my thoughts over the compressor leaking at its body gasket, I've washed down that area a few times and left it to dry and the car to be run as the engine would have dumped some of its heat into the cleaned AC compressor area, and now there are no leaks from that area!

I've now loaded in about 120grams of R134a and the system seems to be working okayish, but with running pressures that are still a bit low, so when/if summer returns, I will load in some more R134a to lift these running pressure and so the AC's performance, it currently can achieve 8.4C at the centre vents, but that is with an ambient temperature of 18C. The reason that I stopped loading it was that the smallish bottle of gas had chilled down too much so the system had stopped dragging the new gas in.

Edit:- my guess, in retrospect was that there were traces of Gunk and maybe brake cleaner remaining in that area, so that was triggering the pumped leak detector I was using and any micro bubbles I spotted when spraying with Gotec leak detector spray, was probably being caused by trapped brake cleaner venting off the gasket/compressor body boundary area.