sunset4000

My A/C has an Issue on my 87 4kcsq.
When the A/C is switched on the evaporator makes a slight hissing noise and the car cuts out everyonce in a while when the A/C is on. Just a slight cut out where you feel it but the rpm does not drop.


Any insight into the issue is appreciated

thanks


One love

Audi

Katman

The cutout is probably what you fell when the AC clutch engages.

Normally, the pulley on th AC compressor is spinning (as the belt is always turning, because the crank pulley is always turning).

But the actuall compressor is not always turning, as it's controlled by the electric clutch (in the compressor pulley).

When the AC system is on, and it decides it needs the compressor on, it turns on the electric clutch.

Nothing elegant here: It just turns turns on the clutch *hard*. With the sudden spike of AC loaded added to the motor, you'll notice a slight 'cutout', until everthing gets up to speed again. May coincide with the hissing noise too, as the AC refridgerant circulates..

You'll normall get that same 'lurch' in power when you turn on the AC.

Situation totally normal!