Low Coolant Light when A/C is on.

[apshaughnessy]

As the Subject states, when I run my A/C in my 86 GT the Low Coolant Light will come on after about 30 minutes of driving. When I got home I checked the radiator I don't see any water at all, letting it cool of first of course. After a breif "HOLY CRAP, It's empty!" moment, I put some water in and drove it around for a few hours to make sure all was good. The car never overheated and never went past the M in Normal even when the radiator was seemingly empty. At this point I started to think it was a simple fluke so I tried the A/C again and whadda ya know, the Low Coolant Light came back on and the radiator need to be refilled. So after a week of the same scenario day after day, I completely give up on A/C and just drive around with the T-Tops off. It has been about 2 months since I gave up on the A/C and the Low Coolant Light has not come on since and the fluid level has been solid as a rock.

So does anyone know what my problem is, because I sure as hell don't.

 

[jerry beach]

If you are losing most of the coolant from your rad. then the temp guage should be coming up. Maybe no water is getting up to it. I would fill the cooling system, start it up with the rad cap off, and top it off untill it gets up to operating temp. Its best to jack the front end up on the drivers side so all the air escapes.

Once it is full, tighten the cap and turn on the AC. Dont drive it, just watch for leaks. That water has to be going somewhere. I would want to have a real temp guage hooked up too, the one in the dash is junk. Sometimes they work OK, sometimes not well at all. Good luck, and hope its something simple like a bad radiator cap.