Nissan 2.5L (151 cu in) firing order — diagram & guide

Over the years, Nissan has made some pretty remarkable engines but one of the longest-lasting four-cylinders in their production is the 2.5-liter one. There’s a reason why the engine has been in production since the early 2000s and still is today and that’s due to its reliability.

Still, we’ve seen a fair share of drivers being confused by the Nissan 2.5L (151 cu in) firing order, which is why we decided to create this guide to help. Once you go through it, you’ll have all the right pieces of information on checking the engine and its cylinders for proper maintenance.

Nissan 2.5L firing order

As a brand, Nissan mostly uses the same firing order for all of its gasoline four-cylinder engines, so that remained unchanged with this one. The Nissan 2.5L firing order is 1-3-4-2 and it’s the same as for the 2.0-liter four-cylinder engine.

If you are wondering what you can do with this sequence, knowing the firing order can help diagnose misfires, oil leaks, or worn-out spark plugs and coils. You just need to know about the cylinder arrangement as well to find the first cylinder and use the firing order to check each cylinder accordingly.

Nissan 2.5L cylinder diagram

The good thing about this engine is that it features a simple four-cylinder configuration. It being a straight-four engine, there are four cylinders arranged from 1 to 4 in a direct pattern, so this makes it easier to identify each cylinder.

We recommend that you start with the first one, which is the one on the left side of the engine. You can move your way up from there towards the right side since the cylinders 2, 3, and 4 follow right up. Just to be clear, we are referring to the cylinder numbers as perceived from being in front of the engine.

When looking at it from inside the vehicle, the first cylinder is on the passenger’s side while the fourth cylinder is towards the driver’s side.

Nissan 2.5L vehicle applications

Before we wrap up this guide, we wanted to give you a list containing all the models of Nissan vehicles that use this engine. It should help properly apply the right firing order, so if you own one of the following models with a 2.5-liter engine, the firing order will be 1-3-4-2:

• Nissan Altima
• Nissan Primera
• Nissan X-Trail
• Nissan X-Terra
• Nissan Sentra
• Nissan Serena

The same engine was used as part of the hybrid powertrain for models like the Nissan Pathfinder Hybrid, Nissan Murano Hybrid, and Infiniti QX60.

Our take

Overall, the 2.5-liter four-cylinder engine proved to be one of the most reliable Nissan engines, and knowing the firing order can only help you preserve it more.

Because of that, we hope that this guide will assist you along the way and that it provides all the necessary bits of information for the proper upkeep of your Nissan vehicle.