how do i know if the oil cooler is working right? cause i have an overheating problem and i have new everything. i have a new water pump, double sleeve pulley, new top and bottom hoses and a new fan clutch also running a 16" fan as well. and still it overheats. especially when i try and go on the highway. anyway have any suggestions? please help.

 

It's probably your thermostat. Is it new? Is it the genuine Mazda factory part with the jiggle pin? Is the jiggle pin at 12 o'clock? Did you test it before installation? If you answered 'no' to any of these questions, go pull it and do whatever it takes to confirm that it is the right part, it is installed correctly, and that it even works as intended (by testing it). Even new ones out of the box have been known to not open all the way, or not open at all. The jiggle pin is important because it helps prevent air from being trapped under the thermostat, rendering it unoperable. Aftermarket units generally don't have this necessary device, so avoid them. The only other thing that is likely to cause the overheating you are reporting is a clogged radiator. Fans don't have any effect on the highway; only when parked. The oil cooler is not going to be a factor unless you are talking about WOT runs or really extended driving under load (lugging it in 5th gear, for example). I've driven RX-7s around town with the oil cooler lines looped (no oil cooler) with absolutely no signs of overheating, including my current peripheral port 13B project car.
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Blake Qualley
Rotary Engine Illustrated