Here's something to try at your own risk.
If it is the same as on the 85, you can short the magnetic fan clutch switch with a wire so the engine fan stays on all the time.
I am not sure if it can be called a recommended procedure, as I am not a mechanic, but I did that on mine and now it runs nice and cool around 80-90 degrees even in the hottest weather, and it gets hot here in HI. To my knowledge, the electric fans should kick on at 100 degrees C, if not there's probably something wrong.
81 300 SD grey/palomino 168K miles
84 190E 2.3 black/grey 64K miles (wrecked)
85 190E 2.3 maroon/palomino 92K miles
88 300E desert red/palomino 204k miles
(made to look like a '94-95)
92 400E desert taupe/creme beige 120K miles
(converted to 94-95 E420 looks)