2016 Nissan Patrol - Overheating in Doha City Traffic

@wqshaider, @johncarguy is giving you perfect advice. The fans are suspect number one. To add to that, another very common issue here is a clogged radiator. The desert sand and dust can build up between the A/C condenser and the radiator, acting like a blanket and preventing proper heat exchange. Even with the fans working, the air they're pulling through is hot. Shine a flashlight through the radiator fins from the front. If you can't see light coming through the other side, it's time for a good clean. You might need to remove the radiator to clean it properly. Also, just to rule it out, when was the last time you changed the coolant and checked the thermostat?

Thank you, @johncarguy and @qatmech. This is very helpful. I checked the fans with the A/C on max. The main fan (on the driver's side) seems to be running, but the second fan (passenger side) is either not spinning or is very slow. I'm not sure if it's supposed to be on with the A/C. I also looked at the radiator, and you're right @qatmech, there is a layer of sand and bugs caked on the front. I haven't changed the coolant since I bought the car used two years ago.

Great observations, @wqshaider. The fact that the second fan isn't spinning with the A/C on max is a huge red flag. On most Patrols, both fans should run at high speed when the A/C is set to max. This is very likely a big part of your problem. The culprit could be the fan motor itself, the relay that controls it, or the wiring. You can try to locate the relay for the secondary fan in the engine bay fuse box and swap it with an identical one (like the one for the radiator fan) to see if the problem follows the relay. If the good relay makes the second fan work, you just need a new relay.

Bingo. You've found two issues at once. The clogged radiator and the faulty secondary fan are a bad combination for city driving. My advice: Address the fan first. Do the relay swap test @johncarguy mentioned. It's free and takes two minutes. If the relay is good, then the fan motor itself has likely failed. You'll need to replace it. Then, clean the radiator. With the engine completely cool, use compressed air or a gentle water stream from the engine side towards the front of the car to blow the debris out. Be careful not to bend the delicate fins. Finally, flush the coolant. Given the age and the overheating, a coolant flush and a new thermostat is cheap insurance. The old coolant may have lost its effectiveness.

Update: I swapped the relay for the secondary fan with the main fan's relay, and guess what... the secondary fan kicked on immediately! So it was just a bad relay. That was an easy and cheap fix, thank you @johncarguy! I also spent an hour carefully cleaning the radiator. The amount of sand that came out was unbelievable. I haven't done the coolant flush yet, but I'm planning to this weekend.

That's fantastic news, @wqshaider! A failed relay is the best-case scenario for that problem. Cheap and easy. Cleaning the radiator will make a massive difference too. I'm confident you'll see a huge improvement even before the coolant flush. Let us know how the temperature gauge behaves after your next drive in traffic.

Excellent work! You've tackled the two main mechanical issues. A new relay and a clean radiator should solve 95% of your overheating problem. The coolant flush will just ensure the entire system is in top shape and prevent any future corrosion. Well done on the diagnostics and repair!