90 RS 305 tbi, mostly stock.

The AC hasn't worked for years, and I finally got around to looking at it today. When I turn it on, the clutch for the compressor will engage and the pulley for the compressor will spin--but then after 4-5 seconds, it stops and the belt just spins around as if the AC were off. Then after 4-5 seconds of being off, it will engage the clutch again, for 4-5 seconds. Then off, then on, then off, then on in a very set rhythm.

So basically the clutch engages, but then something stops it from continuing to engage, and then it keeps trying over and over again to start up again but something keeps stopping it.

Is this an easy fix? Does it simply need a recharge? I don't see any stickers anywhere indicating a conversion to 134a, all stickers point to R12 so it no doubt has been a long, long time. Then again, I always learned that if it needs a recharge, it's got a leak somewhere and a part that probably needs to be replaced.

 

It will normally cycle on & off - but cycles at a faster rate if it's low on freon - and I'm not sure it will cycle at all if the freon is too low, but I'm no expert on A/C. But I do know that cycling on/off is normal.

 

Yeah that's what I know too, it just seems odd that it cycles on and off so fast and so rhythmically. I don't remember the AC ever flat out breaking, going from working one day to not working the next, so maybe it is just out of freon

 

It will cycle faster and faster like that until freon gets so low that it won't build enough pressure to activate it. Sounds like it needs a freon charge and maybe a leak check.