If that valve is ok, could be air in system. My 01 just got new radiator for Xmas. Had to burp it many times.
Its worth looking at the valve, I had heat whole time tho.

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88 ranger xlt ext cab 4x4 2.9l 5 speed
95 ranger reg cab, 4 cyl 5 speed
01 ranger edge, reg cab, 2wd, 3.0 with 5 speed, 4 in suspension lift.