My ac unit blows cold air and will hold a temp but won't shut off and when it does shut off it onlt stops for about 10 minutes than comes on again and runns for 30 to 49 minutes. At night it shuts down longer but still runs through a cycle at least 6 an times a hour. Could it be that hot outside that my unit will not cool quick enough? The unit is about 30 years old. It's a package unit and it's been serviced quite a few times. HELP!!

If it is thirty years old it is probably struggling to keep up. You might want to have someone do a full maintenance on it. Get the outdoor coils clean, check the indoor coils, and check all components to make sure it is working properly. Being it is 30 I would not spend a lot of money on repairs if they are needed. Might be better to change the unit out to a more efficant one and save you some money on your bills. For every 10 years the unit is old you double your electrical use.

If you can get to the unit and turn power off you can clean the outdoor coil with a garden hose. Make sure power is off. Also make sure to change your filters regularly.

How hot is it outside? During extremely hot heat waves that last for days, even the newest most efficient units will run quite often(all depends on insolation of home etc etc.)

I agree with siberianair. A unit that old may need a good going over. But, like he said, don't put too much time or money into it, as its pretty much lived a full life. May be time to look at upgrading. Please let us know how things work out.