Unfortunately, if the air conditioning system is factory original and has not been converted to use the new R-134a refrigerant, you cannot refill the system yourself. R-12 refrigerant is the old stuff, it must be charged by a professional and will be very expensive. They quit making it almost 15 years ago. Depending on your location is could cost upwards of $300 to get it recharged, and if the system is low then you probably have a leak somewhere so that might be $300 out the proverbial window. If you plan on keeping the van, I would suggest that you convert the system to R-134a. A local air conditioning shop can do this for you. I will cost more than just a refill of R-12, but in the long run, it will be much cheaper as the refrigerant is MUCH less expensive should a leak develop.
134 freon
R134a
Yes.
yup
Its located on the accumulator...................
5,500 pounds
The capacity of the 1999 Chevy Express is 15 passengers.
1.6.5.4.3.2
185, to 200.
5x5
On my 1988 Van, it is located on the upper right after you open the rear door. I hope it is on the same location as yours.
.45