I rarely saw the temp on my 240D exceed 100C, even flat-out in hot weather with the AC on.

One summer I did drive through Death Valley, though, and it was 120F in the shade. Climbing out of there I had to shut off the AC, roll down the windows and turn on the heat -- in addition to running a lower gear at less than full load -- to keep the needle on or below the white mark at the top of the gauge. Not fun.

Even so, for the non-turbo cars, as long as they're using good oil there should be no need for the oil cooler.

Ted

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1983 240D automatic, Orient Red, 174K
1983 240D manual, Biscayne Blue, sold at 341K