I've got an old refrigerator made in the early 90's. You can not read the name plate to find out what type of refrigerant it's charged with but it runs a lot, I've cleaned the condenser coil. I noticed that it has a piercing valve on the high side line and I know that those have a tendency to leak. Question is: without knowing what type of refrigerant, what type do you think it might be because I would like to top it off? R 134a?

Early 90's? Maybe R134a, Maybe R12. The EPA banned R12 in 1995. However, refrigerators should have no leakage of Freon! If it leaks at all, you should get it repaired. Handling Freon requires a license nowadays. It's considered a "hazardous material", and they try very hard not to vent any of it into the atmosphere. Special equipment is required if you drain Freon from equipment in order to repair it.

Early 90's? Yes, R 134a. However, refrigerators should have no leakage of Freon! If it leaks at all, you should get it repaired. Handling Freon requires a license nowadays. It's considered a "hazardous material", and they try very hard not to vent any of it into the atmosphere. Special equipment is required if you drain Freon from equipment in order to repair it.

Thanks for the info, I just wasn't positive of the freon. I'll have to look to see if I have a sniffer but when I saw the piercing valve I was suspect. I also have an EPA universal so I know the precautions involved. Thank you

A refrigerator from the early '90 would most likely have R-12 as a refrigerant. Type of refrigerant and amount should be on tag on the door or door frame along with electrical requirements. If it is R-12, a couple of cans will cost you more than the refrigerator is worth.

There are test kits to help determine the type of refrigerent.