Aircon regassing - no effect

[beej]

I took my 102,000 miles 1998 C2 in to regas the aircon at the local garage. The machine confirmed 0kg of refrigerant in the system, detected no leaks, and took 20 minutes to pump in 0.85kg with 10ml of oil. The car was driven out of the workshop into the sun, and when I collected it 30 mins afterwards, the car blew very cold air at me so I was happy.

This morning however, another hot day in the UK, and the car is back to blowing ambient air - it's not cold at all :(

I'm hoping the compressor isn't shot - it can definitely be heard to kick in when the button is pressed - and it worked during winter when it was cold outside.

There aren't many posts I could find about basic aircon maintenance so I'm looking for advice :)

[1999Porsche911]

I took my 102,000 miles 1998 C2 in to regas the aircon at the local garage. The machine confirmed 0kg of refrigerant in the system, detected no leaks, and took 20 minutes to pump in 0.85kg with 10ml of oil. The car was driven out of the workshop into the sun, and when I collected it 30 mins afterwards, the car blew very cold air at me so I was happy.

This morning however, another hot day in the UK, and the car is back to blowing ambient air - it's not cold at all :(

I'm hoping the compressor isn't shot - it can definitely be heard to kick in when the button is pressed - and it worked during winter when it was cold outside.

There aren't many posts I could find about basic aircon maintenance so I'm looking for advice :)

So your mechanic said there was NO refrigerant in the system AND said there were no leaks? Did he think that someone deliberately hooked up a vacuum to the system and sucked it all out?

You have a leak. You need to find the leak AND a new mechanic before recharging again.

Edited June 1, 2009 by 1999Porsche911

[wvicary]

There must be a leak in the system.

[beej]

He handed me a print-out from the machine - which stated it vacuumed no refrigerant out, pumped in 850g and detected no leaks.

Is the compressor in the 996 affected by sitting in the sun? After work yesterday, there was no cold air. But first thing this morning, before the sun could shine on the car, it was blowing cold-ish air (not icy cold, but cold) and I drove to work in luxury. Confusing :(

One option is to go back to the garage and see if the 850g is still in there.

[wvicary]

The system must be tested again, after all what happened to the freon that was in the system to start with?? Temperature does effect the charge pressure slightly. Leaks in this system can be elusive to locate.

[beej]

Update. This time, done PROPERLY.

The leak has been found on the pipework under the car, on the right hand side about half-way between front and rear wheels. The pipe is leaking just under where it is clamped to the chassis. The engineer is investigating options. Is it one single metal pipe running from front to back, requiring engine to be dropped to replace?

[RFM]

The engine can stay in place to replace the metal tube, but it's pretty hard work (LHD cars)

[beej]

Update. The air con pipe was replaced without dropping the engine; it was the forward half of the pipe not the back half that leads to the engine bay. Access through the driver side wheel arch.

Sadly, the cold air lasted a day, and it's gone again. The engineer said that it was gassed with some UV fluid (?) to make it easier to find the (new?) leak. Fingers crossed it isn't the compressor, I've been hoping to avoid the cost of that part :(