Another AC issues thread

B6/7 S4/RS4
#1

Like a few others on here, I’ve been having some issues with my AC. My previous issue (no cold air at all), was due to a bad compressor. That was replaced about a month ago, and since then I never felt the air get as cold as it I believe it should. If I get the temp to 63F, on 90+ days the interior just doesn’t get as cold as my wife’s mdx. The interior does get cool, but not that frigid air that I expect when the temp is set so low.

Any thoughts on what might be causing this?

I logged the HVAC and attached some of the values.

https://lh6.googleusercontent.com/-dFX2nhwAKhY/U8WJvTYKhjI/AAAAAAABgy8/RhmNdGmdGik/w1159-h93-no/LOG-07152014_AC+components.png

Sorry for the crude image.

Also… just recently I threw a high pressure sensor fault and will be replacing that shortly.

Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 BM
Component: A4 Klimaautomat 2833
Coding: 00000
Shop #: WSC 00000
VCID: 6DDA0E552792D676401-5120

1 Fault Found:
00819 - High Pressure Sensor (G65)
07-10 - Signal too Low - Intermittent

#2

How long was your compressor bad? Did they replace the dryer too? That fault is for a bad switch or not enough refrigerant. I’d say the problem is the latter, but if it’s been that way since you picked it up its prob not a slow leak, it may have just not been filled up to the appropriate level. However, not replacing the dryer will also cause poor performance while everything else is in good shape.

#3

Hard for me to tell when the compressor actually went bad. The car was in the shop getting an engine replacement for about 9 months and I got it back in March. I didn’t really start using the AC until late May or early June.

I recently had only the compressor replaced because when the shaft spun, it would wobble (as opposed to spinning perfectly straight) but the compressor never kicked in.

I didn’t have the dryer replaced but may need to start looking at that now - any experience with the complexity of having that replaced?

#4

^yea, I can almost 100% guarantee you your problem (or at least part of it) lies in the fact the dryer was not replaced. These AC systems are fairly finicky, and if the system is open to the atmosphere for very long at all, it should certainly be replaced. . . ask me how I know lol. Same scenario (well motor was out for a couple weeks, but not being “replaced” just upgrading parts).

The stock dryer isn’t too hard to replace, its behind the passenger fog light if I recall. But you need to have the system sucked dry and, swap dryers, and then have them thoroughly suck the system dry before recharging it. Most places just pull it to vacuum and say good enough, but it’s much better to let it really make sure the lines are completely dry after opening it all up.

You might give JHM a call up. I know they have the parts, and it’d probably be worth picking their brain for a bit as I know they’ve done several of these (infact they did mine!).

#5

Thanks for the info maddog!!

I’ll definitely reach out and see what info they can provide.

Sucks this really isn’t that hard of a job but need a pro to evacuate the system - inhaling toxic gases just isn’t my thing!! :stuck_out_tongue: