Hi. I asked the dealer same question some 6 years ago. His response was no. But it may be best for you to ask just to ensure that you do not invalidate any warranty. I have had two 1.8 automatic Zafira over the past 6 years and had no oil cooler added and towed without any problems an ABI Globetrotter Jubilee GT. About the same weight as your Pathfinder.
Hope this helps.
ive always towed with an automatic and never found the need for an extra cooler just dont hammer the car going uphill too much .i tow with a kia carens 1.8 auto at the momment with a large heavy folding camper no problems at all so far touch wood
Hi I have always towed with an automatic. At present we have a nissan almera tino 2.0 litre auto. It can tow our van without any problems. Just take it easy on steep or long hills. If the weather is very hot remember to take more roadside breaks. You wont have any problems.