A/C Compressor

I have an 1991 Astro Van 4.3 litre when I have the air conditioning on you can fill the compressor go on and off while driving. The A/C blows cold air
it still has the original freon in it R-12. Does anyone know why the compressor would go on and off.
Thanks Mike
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Compressors often cycle on and off because the system is undercharged with refrigerant. These GM compressors have a rather traditional problem of wear, and leakage, of the front seal.
But there can be other issues as well.
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You can get a replacement coolant FREEZE 12 for your system. I find it on ebay. Used it in an 87 Bronco and it works great after 3 years. Be sure to check for leaks like the man said.
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