You can either buy a gas identifier or take it to a shop that has one. It will take a sample of the gas and tell you the chemical name.
Was built for R12, can be changed over to R134a.
There is only one Freon, and that is R12. R12 Freon came installed in your 1991 Chevy. It may or may not have been changed over to R134 Refrigerant. If not change it over, as the cost of R12 is unbelievably high an is no longer in production.
The only freon available is R134a. Your car most like came with R12. That means it will have to have the system evacuated at a shop, and then be converted to the R134a. Look at the fittings where the freon is to be introduced to the system....if they are screw on, then your car needs to be changed over to the newer refrigerant....if they are quick connects, you simply need to add R134a.
Yes, freon can indeed cause corrosion. Freon leaks in vehicles can corrode surrounding parts and components in the car over time.
Yes
Freon does not generally need to be replaced. However over time, systems sometimes have a small leak and need to have coolant added. A Freon gauge can confirm if you need to have Freon added.
NO. 1987 - 1989 are the same. When they changed the J arms to A arms they changed the connectors on the harness. The CDI on the newer years have a extra black wire also . DO NOT use this wire ( or ground it) if you use it on older years, or banshee wont rev out. This wire cuts the ignition to only over idle when you have parking brakes on. Just solder on connectors to interchange old and new.
They can be dirty or the system can be low on freon.
Jumpers
remove freon,pressure up system with dry nitrogen to 250psi & go over it all with soap & water .
The cost of auto Freon can come in a wide range of pricing. It can be in the low range of $35.00 for a small hand held Freon tank to well over $350.00 dollars for a large tank.
Yes, look them up, yamaha.com, there are things different that they changed over the years.