Hook up the appropriate gauges before you drop any refrigerant in it.
If you are blowing "ice" cold air on the freeway, I'd wonder how it is you're doing this with an under-charged system?
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.