Red Tek Air Conditioning Refill Kit?

Not really sure what a RED TEK kit is , but if it has anything that says "sealer" on the can , dont use it. If you had to release all the r-134 out of the system , you should have it service by a professional. Ive had prety good luck with refilling 134 systems with the kits that have the lubricant can without any sealer and straight r-134. Flushing out the a/c system is normally only required if it had a catostrophic failure like the compressor failing.