A/C issue

Maybe someone can back this up?

I picked the car up from the shop and mentioned the ac unit to one of the guys. They hooked up thier AC machine and asked me to put the ac on. They said i had free on and the compressor was working BUT the pressure wasnt on the machine read low.

They suggested that there is a valve up around the battery (where the AC lines head toward the car) and they think the valve is stuck and i just need to replace that. Does that sound right?

Valve?? Maybe they’re talking about the Orfice Tube on the passenger side?

Orfice tube/restrictor.

Eddie, are you referring to the high side pressure? The high side should be around 190-200 PSI and the low should be like 30-40 PSI with the AC on.

Well last update, I hope. I got a/c recharged the right way. It was 3/4 lbs low took them about an hr+ to get a vacuum. The shop told me that there must have been a lot of moisture in the system. They did not find any leaks as well. I did have to dispute the a/c repair with the original shop with the cc company. I honestly was going to pay the bill until I found out that they cracked my belly pan and did not put both aux rad shrouds back on. That was the last straw. That’s all I can see right now anyway. I will never use nor recommend that shop and that’s putting it nicely.

I honestly dont know. I just texted him to see, hopefully he comes back with an answer shortly. I do remember him telling me the part was about 170 bucks i think. The way he explained it to me was like he referred to it being similar to the thermostat of the engine. He basically said picture this as a thermostat getting stuck and no ac is getting through like it would for the engine. English is a second language for him btw.

Jimmy the part number is 8K0820679B. Europa parts has one right now for 60 bucks. If what i described sounds right to you let me know asap because i wanna order it for that price.

edited with link.

https://www.europaparts.com/a-c-expansion-valve-8k0820679b.html

Almost seems to good to be true. Let me know what you guys think

this is the part our car uses: https://www.europaparts.com/a-c-orifice-tube-8e0820177.html

I’m not sure if it’s technically an orifice tube or an expansion valve. I’ve seen those terms used interchangeably but technically they are 2 different things, they perform the same function if I understand correctly but some a/c systems use an expansion valve and some use an orifice tube.

when I was sourcing parts for my a/c I saw that Audi sold it at an absolutely insane price, something around $200 iirc, but a generic aftermarket one can be had for something like $5 at rockauto

oops, just realized I was mistaken about that part of my post. I wish this forum allowed posts to be edited. The receiver/dryer was the part I was thinking of that was insanely overpriced by audi at around $200, not the orifice tube.

also, my comment about the orifice tube vs expansion valve is apparently only true if you have a B6. At first glance I thought the expansion valve was only for B8 cars but after looking again now I see that it is also listed for the B7 S4

You have to get to 150 posts before you can edit posts. It is setup that way to discourage the trolls.

The B6/7 S4s use an orifice tube - not an expansion valve. Like what paudi linked to. ECStuning sells them too. https://www.ecstuning.com/Audi-B7_S4--V8/Climate_Control/Air_Conditioning/Valve/

I have seen orifice tubes clogged with shit but usually the compressor had to fail for that.

Jimmy what about the part i posted. They were saying thats the reason im having issues.

Well 2 yrs later and I have to replace the compressor again. This time I’m deciding to do it myself. I started to get the compressor out today. Broke the shaft loose with no problem, as well as the 2 upper bolts. For the life of me I can’t get to that bottom bolt. How do you get to it?

Did you get to it… You have to take the motor mount out to get the AC unit out. It sucks.

I got it, I had to unbolt that hard power steering line that was next to it. The bitch part was getting the compressor to rotate out. I did all of that to find out the shaft striped.

Oh man fuck that. That sucks. Getting the rotational position is hard enough but to get it out and find you have a messed up shaft. Ahhhh.

Yep and also bought a new compressor and condenser and it might not be needed… smh it is what it is. I ordered a new shaft and I hope thats all I need. Upside if I need to replace the gears I had already been planing to having my timing done in the next few months. I already have 90% of the parts.

The hole the shaft goes in was bone dry and it does have the boot. I got a magnet and got out all the metal flakes, then got a vacuum to get more out. Lubed up the new shaft it did not go in super easy, but I didn’t force it in. After some in and out everything was good. Compressor was not seized and spun as freely as the new one and I could also hear suction and pressure coming out of the ports. I pulled the orifice tube and found 6 small flakes and all screens were clean and clear. I’m 99% did not do a good flush so that did not surprise me. What are the chances that the compressor is still and the problem was the shaft?

That’s a hard to call thing.

Its know the AC pumps have been prone to go bad on the S4. Overall I don’t think its directly the pumps issue. As the 2006-2011 A6 S6 and RS4 have the same AC pump. I think there is just something off in the system as those other cars don’t have the same pump failures we do. So its hard to say but I don’t really think the shaft IMHO had an effect on it.

Well with the teeth on the shaft striped, the shaft could no spin. That’s what I was thinking.

Yeah that makes sense. It would obviously depend on if the shaft stripped working to get it out or it was casued from some other issues.

You would think if the pump spins free and easy once off the car that there wouldn’t be an issue there.

Take the 6 Allen bolts out of the back of the compressor, pull off the black plate on drive part of the compressor, and look if the center portion inside has split from the part that spins. I recently had an AC compressor failure shortly before an event that went bad on multiple levels. The compressor siezed and the part that spins inside broke off because the engine has to keep turning. The driveshaft for the AC compressor was stuck in the plate so badly that I rounded the 19mm part of the plate trying to loosen it. Ended up getting a new OEM AC compressor (not a Nissens one) and I also had to replace the little driveshaft too in addition to the drier and orifice tube.