bolt_007

I would like some advice on my cars AC system it blows very cold and then after some time it blows very warm air with a slight smell to it. does not matter if I am driving the car or idling. although idle is warmer than when driving, but that is normal on most cars.

I have only just put a new compressor, drier and orifice tube, system was then recharged and pressures read proper.

Now I have a feeling I might have put the (yellow/white) orifice tube in backwards. I removed a black orifice tube from the system so I might have put a different size orifice tube in as well. I am waiting for a reply from the orifice tube supplier on the size of the opening. on the yellow/white orifice tube. I do not know what size opening on the black orifice tube. everything I have read says the A6 should use yellow/white 0.062" or grey/white 0.072"
I am thinking the yellow/white one might be for cooler climates. and the grey/white might be for hotter climates, could someone please help

sorry if my writing is confusing.

rocketman4321

Not sure I can help with the tube. But the warm air suggests the AC isn't running at all after a while. (The smell is probably from the condensate pan.) If this happens at idle, can you see the compressor clutch and make sure it's engaging, and not slipping? You could also check the pressures when it's failing to confirm there's no compressor operation.

My thinking is that a wrong size orifice would cause poor operation, but not complete failure--it is still an orifice and the refrigerant must still act on it, even if the amount is less or more than optimum.

bolt_007

Ac
I think the compressor is still running when it blows warm air, (I will take it for a drive this evening and have a look at the compressor when it starts to blow warm air and see if the ac clutch is working.

This is what I am thinking, the evaporater is freezing up and limiting the amount of air flow and temperature that can get inside the cab. I am not sure how to test my theory though.

rocketman4321

You might be able to tell by the gauges, if you compare working and not-working. I think you can also tell by the temperature of the vapor (larger) line returning from the evaporator, but I'd have to look that up to be sure.

Any way to get a look at the evaporator? I haven't tried on this car. I have one of those USB "pencil" TV cameras (~$25) that's useful for fishing into tight spots. But you might be able to drop one of those down a duct or in the blower opening.

bolt_007

I took the car for a half hour drive last night. I pulled over when the ac got warm and checked the ac clutch it had stopped spinning, it started spinning again and then cycled off in about a minute. I then touched all of the ac pipes I could see the only one that was cold was the one with the orifice tube in it and only as it went into the firewall none where hot or freezing.

The inspection camera is a good idea but will have to wait until I am home next.

Thank you guys for the help

rocketman4321

Cycling on for a minute or so may be normal. Should continue to cycle on-off to maintain the temperature. If it is, then something in the control system thinks it's getting cold.

bolt_007

So if the system is thinking it is getting cold. what sensors should I check? and how to check them?

thanks everyone for the help

bolt_007

Ok so have had the system regassed twice now, no leaks but we changed the orifice tube in case there was a blockage. So ac system all gassed up and we took it for a drive with the manifold gauges hooked up and we discovered that under any acceleration the ac compressor shuts off. All pressure are in spec and as soon as you let off the gas pedal ac kicks back on does not matter how gentle you are to the accelerator

anyone have any thoughts on this
please help

bolt_007

bump

bolt_007

bump bump

anyone have any ideas ?