How To Diagnose A Failing Radiator Fan

A malfunctioning radiator fan causes the engine to overheat, which is a pretty serious problem.

The radiator fan’s primary job is to cool your radiator and engine. It’s especially important when your Nissan is idling or driving too slowly to to force air through the radiator. So when your radiator fan stops working, your engine temperature rises quickly.

If overheated long enough, the engine will fail. The engine damage will be either irreparable or very expensive to fix. The best way to prevent engine damage is to keep an eye on your radiator fan, diagnose radiator fan failure, and then replace it ASAP if necessary.

Why Does A Radiator Fan Fail?

Radiator fan

Image Credit: CarsNToys

Most commonly, radiator fans stop working because of one of these issues:

  • A blown fuse
  • Faulty wiring
  • A broken temperature sensor
  • Fan clutch failure

Have you determined that your radiator fan is bad? It’s worth taking some extra time to pinpoint the issue and fix it (if necessary) before installing the new radiator fan. That way, you’ll have the peace of mind that your replacement radiator fan will run properly without the underlying issue getting in the way again.

Warning Signs Of A Failing Radiator Fan

Knowing the symptoms of a malfunctioning radiator fan will allow you to diagnose the problem and replace the radiator fan in a timely fashion. If your Nissan starts to show any of the following symptoms, you may want to check your radiator fan:

  • Engine continually running hotter than normal, even when you’re idling or driving slowly
  • Loud fan noise coming from under the hood
  • Blown fuse

Testing Your Radiator Fan

If you have a hunch that your radiator fan isn't working properly, the good news is you don't have to pay a dealership for an official diagnosis. You can set aside 10-15 minutes and take the following steps:

  1. Start your car and take it out for a spin until the engine reaches normal temperature.
  2. Pull over.
  3. Set the heater to cold (but don't turn the air conditioner on).
  4. Let your car idle for 5 minutes. Watch the temperature gauge. The engine temperature should either stay normal or fall back to normal. If it keeps rising, then it's likely the radiator fan hasn't kicked in or it's not spinning fast enough.
  5. Pop the hood and watch your radiator fan spin. Watch how it engages. If it does spin, determine whether it's consistent or strong enough. (Don't touch the fan or put your hands or face near it. It is spinning with much more force than a household fan.)

If you find that you have a malfunctioning radiator fan, it’s pretty important to replace it right away to avoid engine issues or failure.

Replacing Your Radiator Fan Doesn’t Necessarily Have To Be Expensive

It’s normal to hesitate before splurging on a radiator fan replacement, especially if you’re on a budget. It can be pretty pricey if you’re paying for labor and a markup on an OEM part at a Nissan dealership.

Nissan radiator fan

However, there are ways to save money on a replacement:

  1. Buy a genuine OEM replacement radiator fan from at wholesale pricing
  2. Replace the radiator fan yourself (here’s a tutorial on replacing a Pathfinder radiator fan assembly).

Here are a few fast links to our best selling OEM radiator fans at wholesale pricing:

  • Part No. 21481-ZY70A: For 2009-2014 Maximas
  • Part No. 92120-ZS20A: For 2008-2012 Pathfinders
  • Part No. 92120-EA200: For 2005-2007 Frontiers, Pathfinders, and Xterras