I have a 1997 A6 Avant 2.8 and need a bit of help with instructions about getting the A/C working. The OBD shows low pressure.

I’m cheep –I mean CHEEP really CHEEP – so I’d like to stay away from a shop unless there is no other option. In the old days I was able to add a can of refrigerant to keep ahead of a slow leak in a pickup truck but don’t know if it can be done in an Audi.

Does anyone know of a link that gives info about adding refrigerant to the system? It has to simple so even I can understand! I assume it takes R134… and would like to try before spending a bunch of money at a shop.

PS I bought the car last fall and the person said the A/C worked – – but can’t be sure…

 

Am I corect in saying that the low pressure schrader valve is under the cowel and it has the low pressure swith attached?

Bently says that I can remove the switch without letting the R143 out. Is that right?

 

You probably can't charge the system yourself. You need an adapter from audi to do it off the a/c compressor as the picture shows below.




Vehicles with no Connection on Low-Pressure Side of Refrigerant Circuit



On the following vehicles, no service connection is provided for the A/C service station on the low-pressure side of the refrigerant circuit. Adapters are required for connecting the A/C service station to the refrigerant circuit of these vehicles.



t
Audi 80, Audi Cabrio, Audi Coupe



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Audi A4 up to 07.96



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Audi 100/ Audi A6 up to 03.97



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Audi A8 up to 11.97
Note[/align]



On vehicles with no or inaccessible connection at compressor, remove A/C Refrigerant Low Pressure Switch -F73- (jumper contacts in connector for A/C Refrigerant Low Pressure Switch -F73-) and screw adapter to this connection

 

Connecting with Air Conditioning Adapter Set V.A.G 1786



A-
Connection with valve (small valve insert) on low-pressure side of refrigerant circuit



B-
Adapter with nut -V.A.G /1-



C-
Commercially available charging hose (short version with 5/8" thread on each end)



D-
Adapter with service connection -V.A.G /2- (for connection of quick-release coupling of A/C service station -E-)
Note[/align]


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Assemble adapter and charging hose as shown and connect first to connection with valve -A-.



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Adapter with nut -V.A.G /1- is only to be used at connections with “small” valve insert (standard for connection with valve for A/C Refrigerant Low Pressure Switch -F73- and also gradually introduced as of 10.94 at compressor).



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Instead of adapter with nut -V.A.G /1-, use can also be made of adapter -V.A.G /10- (remove valve from adapter -V.A.G /10- or install valve opener in charging hose).



Connecting with Adapter VAG/10









–
Unscrew cap from connection with valve -A- (at compressor).



–
Attach O-ring -B- to connection (8.9 mm; 1.8 mm).



–
Screw adapter V.A.G /10 -C- to connection -B-.



–
Install valve opener -D- with appropriate seal in charging hose connection.
Note[/align]


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The type of valve opener -D- and seals required depends on the charging hose used (specific to manufacturer).



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The quick-release coupling adapter is not required for connection on the low-pressure side of Audi vehicles.



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Screw charging hose -E- (to A/C service station) to adapter - V.A.G /10-.
Note[/align]









To minimize the amount of air and moisture penetrating into the charging hoses and thus into the refrigerant circuit, the charging hoses should be connected together as illustrated.



A-
Charging hose to A/C service station



B-
Hand shut-off valve



C-
Charging hose (short version) with valve opener for connection to adapter -D-



D-
Adapter - V.A.G /10-



E-
Charging hose (short version) with quick-release coupling adapter (for vehicles with quick-release coupling adapter on low-pressure side)



–
Perform planned tests and measurements.

 

Thanks for replying auditech79

I can't figure out how to paste Bentley info here so I'll attempt to describe what I'm trying to do.

In the section listed as -

Audi > C4 > 1992 - 1998
Heating & Air Conditioning
87 - Air conditioning[/align]A/C refrigerant low pressure switch -F73-[/align][/align]it says [/align]
[*]Removing and installing [/ul]

Remove plenum tray. [/align][/align]

Remove electrical connector and unscrew low pressure switch -F73-. [/align][/align]
Refrigerant system remains closed (Schrader valve under switch) [/align][/align][/align] Install new O-ring -A- (8.9 mm x 1.8 mm), lubricate with refrigerant (PAG) oil and ensure proper seating in groove. [/align]
Torque switch to 5 Nm (44 in lb). [/align][/align]
Install plenum tray. [/align][/align][/align][/align]Since the Schrader valve gives access to the low pressure side do you think it is possible to use it to addsome R134?[/align]In an extreme case I could jumper the swith to get the compressor going but all I really want to do is give it a shot of refrigerent to see if there is any way I can get the system working without spending a zillion dollars at my local Audi dealer.. [/align][/align][/align][/align]

[/align][/align]

 

Info is not 100% correct, you most certainly can charge the a/c system, remove battery cover cowl, find high and low pressure taps on the pass. side, as long as the compressor still runs then you can draw the r134a into the low side. I must caution this action as the system are fairly critically charged 0.75kg is the total charge, also this really should be undertaken by an a/c tech as they will have proper gauges, scales, vacuum pump, all the things necessary to do it right. But if you want cheap and unreliable then grab up some r134a and fill away

 

There is no low port on the passenger side on early A6's, i think NH_USA knows that.

As for removing the switch, its a lost cause to try without the correct adapter tools to hook it up to. Elsa web also mentions using the switch to charge the a/c but you would still need a different adapter than i showed in my illustration.

 

sorry my bad, thought we were talikng C5, C4 can be charged through the switch but you are correct in saying that an adapter is required. I find that A/C is best left to pro's. Again sorry my bad

 

Thanks guys - Looks like I have a choice of either being hot orspending a bunch of money...

If I procrastinate long enough it will be winter and I won't have to be concerned about the heat.


Why can't Audi make things simple? [sm=boohoo.gif]

 

How much does the adapter cost? If it is 100 bucks or less, it might be worth buying. you will easily spend 2-300.00 at an A/C shop. I would call the dealer and at least find out how much it is before resorting to baking all summer long.