Air Con Leak - Low Pressure Side

[willdudeuk]

What will just replacing the expansion valve achieve?

will just replacing the compressor clear the above faults?

im not sure I can afford a new one at the moment - they aren’t cheap!!

[willdudeuk]

Well looks like I’ve got no ac now so guess I’ve lost the refrigerant somewhere overnight. Not blowing cold at all.

So will I need to replace Expansion valve and compressor?

Dont think I’m keen on replacing the evaporator. That job looks evil. That’s dash out / cross car beam / HVAC unit. Don’t think I’m keen on that at all.

is expansion valve easy enough to do? Can you do it from the top or is there better access from underneath?

[willdudeuk]

I replaced the valves in both the low pressure and high pressure pipes as it appeared that one of them was "bubbling" so this could of been a cause as to why i lost all the refrigerant overnight.

When we got it back on the machine it read 0 bar.......

Regassed it now....but wasn't achieving 8 degrees c, only about 14 this time....so must be a bad compressor.....


Replaced both valves with 8E0 820 855 genuine from dealership.....

But after regassing both appeared to be bubbling as well.....

I made sure to tighten them well with the valve tool....


Perhaps the threads have gone on the pipes?

[Crasher]

My mechanic Matt ran into this with his 1.4 TSI Golf 5 a few days ago, he recommissioned the AC after it had been dead for years and it worked, then it stopped and the compressor has failed, they suffer a very high failure rate. He is in denial and is trying to find any way of avoiding changing it.

[willdudeuk]

Well it’s lost all the gas again after replacing the valves.....

Which pump do I need?

Ive found a new genuine one with part number 1K0 820 859 T

are these exchange / recon units from factory? (Pump says T but box has TX).

[willdudeuk]

Going to replace the compressor with 1K0 820 859 T and hopefully see what happens.

Should I replace expansion valve at same time one it’s been vacuumed? It doesn’t have any pressure at the moment showing 0bar.....so it’s leaked out somewhere again.

The compressor looks like probably OEM part and looks a bit knackered to be honest.

Can’t see any leaks with UV torch though. Have checked as thoroughly as I could. The oil / lubricant we use has some uv dye in it but can’t see anything obvious.

I replaced the schrader valves for both the low pressure and high pressure lines but could still see it bubbling after we regassed it. Any reason why this would be happening? Could the threads or refrigerant pipes be knackered?

is replacing compressor first a better idea seeing as they are a common failure?

[Crasher]

There is no point doing the compressor until you find the leak, the most common cause is the pressure sender.

[willdudeuk]

I did replace the pressure sender / thrust sensor with the following part.....5K0 959 126

replaced the o ring seal too

cant seem to find a leak here unless the part is wrong? You can see in the picture that the old part looks different to the new one?

9C6E6233-010F-4704-B7E1-011C371545FA.jpg

[Crasher]

That is the correct updated sender, have you done a UV dye leak detection test?

[willdudeuk]

I am about to do it with some Wurth leak detection dye (Art. No. 892 764010).

Hopefully should be able to find the leak with this and a UV torch.

A30FE6F0-C8E3-4DC9-ABC0-F7C0C925BB68.jpg