1997 A4 2.8L v6 FWD. I have a small leak in the A/C system somewhere. It takes about 2 months to leak out enough to where the air coming out is not cool enough to be of any use to where I need to charge the system. I have added dye a few times and cannot find the leak at all. I have also brought it to a shop and they said it was the compressor leaking and showed me the glow of the dye. I was not convinced since in my opinion I felt I had to convince myself that it was actually dye I was seeing. I say this because the small amount that sprayed around the low side port and that I spilled on the ground lit up like a beacon - it was very obvious this was dye. Not the case at all on the compressor and what I saw on the compressor.

I also tried one of those sniffers that beep. Nothing even around the compressor. I had both the high/low side valves replaced too.

Any ideas would be helpful - thanks.

 

Probably a seal somewhere. Hopefully it's not the heater core.

 

I'm confused - what does the heater core have to do with the A/C and leaking refrigerant. Thanks

 

I'm sorry. I meant to say "Evaporator". An equally shitty problem to have.

(To be clear - and hopefully not condescending: The evaporator is the A/C system's equivalent of the heater's heater core.)

Hope that helps clear things up (again: My Bad).

G/L

 

Yes hopefully it is not the Evaporator. I did use the sniffer type leak detector in the car near the vents and nothing signaled of real consequence. Will check again though.

Thanks again.

 

Just check your pressure. That'll tell you for sure if you have a leak or not.

 

I put it on a vacuum and after 30 minutes turned it off (closed the valves to the gauges) and slowly lost the vacuum. So other than losing r134 I did confirm the leak.

I literally just thought of a question. Can the system lose vacuum through the compressor under the conditions above. Still not convinced it is or is not the compressor but if it cannot that would tell me it is not the compressor.

Like you said I sure hope it is not the evaporator.

Thanks.

 

There are two lines on the compressor, so it's entirely possible one could have a bad o-ring, etc.

I would check my system by checking pressure on the high side, not vacuum on the low side.

 

Thanks- I will look into that. Maybe a dumb question but could it leak through the seal where (if I am using the correct language) the pulley is.. the shaft seal(?) if not running.

 

No. It would leak from an o-ring or a crack in a hose, the condenser or evaporator.