A/C needs a recharge. How can I tell if the former meticulous owner converted it to R134? He is old and can't remember... Thanks.

Car is US Spec 1990 300D 2.5Turbo.

__________________
Meek

1977 Volkswagen Golf GTi (sold)
1981 Audi 5000S Turbo (sold)
1982 Volkswagen Rabbit LS 145k (sold)
1983 Volkswagen Rabbit GTi 150k (sold)
1984 Saab 900 150k (sold)
1984 Volkswagen Scirocco GTX 1.8T 20V
1985 Mercedes Benz 190E 2.0 160k(sold)
1986 Mercedes Benz 190E 2.3-16 188k (sold)
1988 Volkswagen Fox 161K (sold)
1990 BMW 525td (Sold)
1990 Mercedes Benz 300D 100k
1994 Saab 900 SE Turbo 55k (sold)
1996 Volvo 855R 140K
2001 VW Jetta Wolfsburg 16k (sold)