I have 2 89 Range Rovers and recently had to remove and have a radiator shop clean one the radiators due to restrictions. No problems since.

Good Luck.

(Didn't know if the one at issue was a classic though so may not be applicable)

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2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
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1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member