I have a 1990 crx SI..

I had a shop convert the AC system to 134a, it works, but now the car is overheating and surging at idle. It didnt do it before.

Could the AC be the cause?

could I just take off the belt for now, so the AC would be disconnected?

 

yes it can be the cause and taking off the belt will be the easiest way to find that out for sure

 

although the extra load it puts can be the cause, it shouldnt be. if you havent done it in a while id put a new oem thermostat and test the coolant. making sure to bleed all the air out of the system. if you op the rad cap and its all funky, you could have restrictions in the radiator.