an oil cooler will be the least of your worrys and if there were ANY major problems with you oil the engine would be totally fecked already.. you want an oil cooler more than you need it.. i bought a 10 row oil cooler for my r5gtt because i wanted it, not because i needed it... it looks cool in the front grill and im not ashamed to say it:rasp:
if you have running problems your looking in the wrong place.. your cars old now and flushing your rad out would make more sense, as would blasting a hose pip into the heater matrix as most are blocked these days.. i did this to mine a while back and there was loads of sh1te coming out + it fixed my heating in the car
changing the gearbox oils a good idea and when cars get old people dont bother to do it.. maybe change the brake fluid as people forget it with DIY servicing.. wd40 your nipples tho as they will break:dapprove: