Air con prob

[silversteve]

Hi all,went to have my air con re-gased today ( 1993 V6 Quattro Coupe 2.8 ) Anyway after telling me my gas was not used anymore he filled with " modern " stuff, no leaks found and seems to hold pressure fine. The prob seems to be that when the air con button is pushed the compressor kicks in the cuts out within 4-5 secs???
He checked the high pressure switch and air con relay and all seem fine,is there another switch somewhere that could be causing the prob? or has another forum member had this issue? Found this posted by Jamo " What model / engine are you interested in ?

The information I have is clear that 5-cyl models are different from V6 and 4-pot engines. I can dig it up for you no problem."

Was hoping i could get a piccy/schematic of the system for my Coupe,thanks in advance for any help, Steve

[johne]

"Modern" stuff is R134a and your system will work fine on it.

My guess is that your system has been filled with too much or too little gas, most likely too little (or you have a leak) so that as soon as the compressor kicks in the system pressure drops below the setting for the low pressure switch which cuts the feed to the compressor clutch causing the compressor to drop out.

It's the low pressure switch which is critical to the system operation, so that's the one to check if you do have the correct amount of gas.

I suggest you go back to where it was filled, get them to connect gauges to the high & low sides and then monitor the pressures as the compressor kicks in.

John

[Jamo]

Hi all,went to have my air con re-gased today ( 1993 V6 Quattro Coupe 2.8 ) Anyway after telling me my gas was not used anymore he filled with " modern " stuff, no leaks found and seems to hold pressure fine. The prob seems to be that when the air con button is pushed the compressor kicks in the cuts out within 4-5 secs???
He checked the high pressure switch and air con relay and all seem fine,is there another switch somewhere that could be causing the prob? or has another forum member had this issue? Found this posted by Jamo " What model / engine are you interested in ?

The information I have is clear that 5-cyl models are different from V6 and 4-pot engines. I can dig it up for you no problem."

Was hoping i could get a piccy/schematic of the system for my Coupe,thanks in advance for any help, Steve

Erm when did I post that? as I know sweet FA about the V6

[silversteve]

Erm when did I post that? as I know sweet FA about the V6

I really should not spend so much time in the sun........ Sorry Jamo it wasnt you,got a little ahead of myself.......... Have Pm'd the person who did post it now

[silversteve]

many thanks Johne will get him to check,any idea where low pressure switch is in case its that???

[s2driveruk]

yep sounds very much like too little gas, the compressor will run engaged permanently when there is sufficient gas in th circuit. once it drops then it starts to cycle...

Surely an aircon 'specialist' would be checking what the correct fill is for the car model and ensuring its holding the pressures before taking your hard earned! Check the pump though for a seal leak as mine leaks a little from there but I think is heat related so a deep vac to check its airtight may not show up tht problem too. Mine held 200mb for 30 mins no probs but as soon as the system was running is did weep.

[johne]

many thanks Johne will get him to check,any idea where low pressure switch is in case its that???

See this set of posts,

http://www.s2forum.com/forum/showthread.php?t=45221

John