2018 Nissan Altima Power Steering Fluid

The 2018 Nissan Altima, a popular mid-size sedan, relies on a hydraulically assisted power steering (HPS) system to ease the driver's effort in maneuvering the vehicle. Understanding the intricacies of this system, particularly the fluid it utilizes, is crucial for maintaining optimal performance and longevity. This guide delves into the specifics of the 2018 Altima's power steering fluid, its function, maintenance, and potential issues.

Understanding Hydraulic Power Steering (HPS)

Before diving into the fluid itself, let's briefly review the workings of a typical HPS system. The system consists of several key components:

Reservoir: This holds the power steering fluid, providing a supply for the entire system.
Pump: A vane or rotary pump, usually driven by the engine via a belt, generates the hydraulic pressure.
Hoses: High-pressure and low-pressure hoses connect the various components.
Steering Gear (or Rack): This unit contains a valve that directs the pressurized fluid to either side of a piston, assisting the driver in turning the wheels.
Piston and Cylinder: Within the steering gear, the piston moves within a cylinder, providing the mechanical force to turn the wheels.

The fluid acts as the lifeblood of the system, transmitting the pressure generated by the pump to the steering gear, enabling smooth and effortless steering. When the steering wheel is turned, the valve in the steering gear opens, directing fluid to the appropriate side of the piston. The pressure on the piston then assists the driver in rotating the wheels.

The Specifics of 2018 Nissan Altima Power Steering Fluid

Fluid Type and Specifications

The 2018 Nissan Altima typically utilizes a specific type of power steering fluid. While general-purpose power steering fluid might work in a pinch, it is strongly recommended to use the fluid specified by Nissan. Using the incorrect fluid can lead to damage to the system components, including seals and hoses, due to incompatibility issues with the materials used in the system.

According to Nissan service manuals and owner's handbooks, the 2018 Altima generally specifies a fluid that meets or exceeds Nissan's PSF-II specification. It is imperative to check the owner's manual or consult a Nissan dealership to confirm the exact specification for your specific Altima model, as subtle variations may exist depending on the engine or specific trim level.

While finding PSF-II specifically might be challenging, many aftermarket power steering fluids are formulated to be compatible with Nissan vehicles and meet or exceed the performance requirements of PSF-II. Look for fluids that explicitly state their compatibility with Nissan vehicles or that meet Nissan's power steering fluid specifications. Some fluids may be labeled as "Dexron III/Mercon" compatible, and while they might be technically compatible, it's best to stick with fluids that explicitly state Nissan compatibility.

Always err on the side of caution and verify the fluid's compatibility with your specific 2018 Altima model. Using the wrong fluid can lead to:

Premature wear and tear of the power steering pump.
Leakage due to seal degradation.
Reduced steering performance.
Increased noise from the power steering pump.

Fluid Characteristics and Function

Power steering fluid is more than just a hydraulic medium. It also serves other crucial functions:

Lubrication: It lubricates the moving parts within the pump and steering gear, reducing friction and wear.
Cooling: It helps to dissipate heat generated by the pump and steering gear.
Corrosion Prevention: It contains additives that inhibit rust and corrosion within the system.
Seal Conditioning: Some fluids contain additives that help to keep seals pliable and prevent leaks.

Therefore, maintaining the fluid's condition is paramount to preserving the system's health. Over time, the fluid can degrade due to heat, oxidation, and contamination. This degradation reduces its lubricating properties and can lead to the formation of sludge and varnish, which can clog the system and damage components.

Checking and Maintaining the Power Steering Fluid

Checking the Fluid Level

Regularly checking the power steering fluid level is a simple yet crucial maintenance task. The reservoir is typically located in the engine compartment and has a dipstick integrated into the cap or markings on the reservoir itself indicating the "MIN" and "MAX" levels. Follow these steps:

Locate the power steering fluid reservoir. Consult your owner's manual if needed.
Ensure the engine is cool.
Clean the area around the reservoir cap to prevent dirt from entering the system.
Remove the cap and check the fluid level.
If the fluid level is below the "MIN" mark, add fluid until it reaches the "MAX" mark.
Use the correct type of fluid as specified in your owner's manual.

Note: If you frequently need to add fluid, suspect a leak in the system and have it inspected by a qualified mechanic.

Changing the Fluid

While Nissan does not explicitly state a specific interval for power steering fluid changes in the 2018 Altima's maintenance schedule, it is generally recommended to change the fluid every 30,000 to 60,000 miles, or every two to three years, depending on driving conditions and usage. Heavy usage, such as frequent stop-and-go driving or driving in extreme temperatures, may warrant more frequent fluid changes.

Changing the power steering fluid involves removing the old fluid and replacing it with fresh fluid. There are two primary methods for doing this:

The Turkey Baster Method: This involves using a turkey baster or similar tool to extract the old fluid from the reservoir and replacing it with fresh fluid. This method is simple but only replaces a small amount of the total fluid in the system. It is best suited for refreshing the fluid regularly, rather than a complete fluid change.
The Full Flush Method: This method involves disconnecting a return line from the power steering pump and allowing the pump to push the old fluid out of the system while simultaneously adding fresh fluid to the reservoir. This method replaces virtually all of the fluid in the system and is the preferred method for a complete fluid change. This method requires more technical skill and attention to detail to avoid damaging the power steering pump by running it dry.

Regardless of the method used, it is crucial to use the correct type of fluid and to avoid introducing contaminants into the system. If you are not comfortable performing this task yourself, it is best to have it done by a qualified mechanic.

Troubleshooting Common Power Steering Issues

Several symptoms can indicate problems with the power steering system or the fluid:

Hard Steering: Difficulty turning the steering wheel, especially at low speeds, can indicate a low fluid level, a failing power steering pump, or a clogged system.
Noisy Steering: Whining, groaning, or squealing noises when turning the steering wheel can indicate a low fluid level, air in the system, or a failing power steering pump.
Leaking Fluid: Visible leaks around the power steering pump, hoses, or steering gear indicate a damaged seal or hose.
Foamy Fluid: Foamy or milky-looking fluid in the reservoir indicates air in the system.
Dark or Dirty Fluid: Dark or dirty fluid indicates that the fluid has degraded and needs to be changed.

If you experience any of these symptoms, it is essential to address the issue promptly to prevent further damage to the system. Start by checking the fluid level and condition. If the fluid is low, add the correct type of fluid. If the fluid is dirty or foamy, consider changing it. If the problem persists, consult a qualified mechanic for further diagnosis and repair.

Conclusion

Maintaining the power steering system, particularly the fluid, in your 2018 Nissan Altima is vital for ensuring smooth and effortless steering and prolonging the life of the system. By understanding the function of the fluid, regularly checking its level and condition, and changing it as needed, you can help prevent costly repairs and enjoy a more comfortable and safe driving experience. Always refer to your owner's manual for the most accurate and up-to-date information regarding your specific vehicle.