the 280 and 300 zx have oil coolers. i looked at the apparatus and i think that its a screw on application some sort of bracked, i found it on the turbo ones and one turbo 300 zx but i think that this was a factory option? saw others without it ill have the scoop on it in a few days, thats all im missin in the cooler family looks like an interesting setup tho, "someone" might wanna kno about this for that turbo setup to keep that oil of yours cool...

 

As far as the 79-83 280ZX cars; only the 280ZX Turbo with automatic transmission came with an oil cooler! Odd, one would think that all the turbo cars would need one. I guess they thought that the auto would run hot because of the rpm's caused by the auto 3 spd. (Overdrive was not an option until the 300ZX on the Z-cars. I know that at least the 82 and 83 Maxima got the 3+OD trans. It can be put into a Z-car with some work).