Above posts are point on - you're oil is incorrect for the refrigerant you are using. Have it vacuumed at a shop for 1hour+ and put in proper R12. Cans you buy from auto parts stores labelled R12 are not the real thing.

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1976 Mercedes 240D (Sold)
1985 Mercedes 300D Turbo Diesel: 500,000KM
1986 Mercedes 300E (Sold)
1988 Mercedes 300E (Sold)
2002 Mercedes C240 (Sold)
2008 Mercedes C350 4matic

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