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INFINITI I35 (2002-2004) Engine Oil Pressure Switch: A Comprehensive Guide

Understanding the signs of a failing oil pressure switch and how to choose the right replacement for your I35.

4 minutes to read 2002-2004 INFINITI I35
Difficulty
2/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$70-$140
🚫 Do not drive — Do not drive the vehicle if the oil pressure light is on, as you cannot be sure if it's a faulty sensor or a true lack of oil pressure, which can cause catastrophic engine failure.
Key Takeaways
  • Always check your oil level first if the warning light comes on; never assume it's just a bad sensor.
  • A visible oil leak from the switch itself is a clear sign it needs immediate replacement.
  • Replacement is a simple DIY task for most owners, requiring access from under the vehicle.
  • For this critical part, choosing a reputable aftermarket brand like Standard Ignition or Beck Arnley is a wise investment over budget options.
The engine oil pressure switch on your 2002-2004 INFINITI I35 is a critical sensor that monitors the engine's oil pressure. It's a simple but vital part, also known as an oil pressure sending unit. Its job is to alert you if the oil pressure drops to a dangerously low level. When pressure is normal, the switch is open. If pressure falls below a specific threshold (typically 5-7 PSI), the switch closes, completing an electrical circuit that turns on the red oil pressure warning light on your dashboard. This gives you an immediate warning to shut off the engine to prevent catastrophic damage.

Is Your INFINITI I35 Oil Pressure Light On?

A glowing or flickering oil pressure light on the dashboard of your 2002-2004 INFINITI I35 is a serious warning. Your first step should always be to safely pull over, turn off the engine, and check the oil level using the dipstick. If the oil level is correct, the problem could be the oil pressure switch itself. These switches can fail over time, leading to false warnings or, more dangerously, no warning at all when there is a real oil pressure problem.

Common Failure Symptoms

A failing oil pressure switch on the I35 can cause several issues. Recognizing them early can save you from unnecessary worry and potential engine damage.

  • Flickering Oil Light: The oil pressure light may flicker or come on intermittently, especially at idle or during turns.
  • Oil Light Stays On: The warning light may stay illuminated even when you know the oil level is full.
  • Visible Oil Leak: The switch itself can develop a leak. You might see oil residue on the sensor or drips on the ground below it. Forum users have reported leaks where the plastic and metal parts of the switch are joined.
  • Incorrect Gauge Reading: While the I35 uses a warning light, a faulty switch can cause erratic behavior if connected to an aftermarket gauge, such as reading zero or maxed out.
Warning: Never ignore an oil pressure warning light. Even if you suspect a faulty sensor, driving with low oil pressure can destroy your engine in minutes. Always verify the oil level first.

Choosing an Aftermarket Oil Pressure Switch

For the 2002-2004 INFINITI I35, the OEM (Original Equipment Manufacturer) part is a reliable choice, but quality aftermarket options can offer significant savings. When shopping for an aftermarket switch, brand reputation is key. The brands available in our inventory range from well-known OE suppliers to budget-friendly alternatives.

  • Premium Aftermarket (e.g., Standard Ignition, Beck Arnley): These brands often aim to meet or exceed OE specifications. Beck Arnley, for example, has a history of sourcing parts from original equipment suppliers, though it's important to note that sourcing strategies can change. Standard Motor Products (Standard Ignition) is another established name. These are generally a safe bet for quality and fit.
  • Standard Aftermarket (e.g., Walker Products, Facet): These brands provide a balance of quality and value, making them a popular choice for many repairs.
  • Economy Brands (e.g., Global Parts): While the most affordable, these parts are best for those on a tight budget. Quality can be inconsistent compared to premium brands.
Pro Tip: For critical sensors like the oil pressure switch, many experienced mechanics and owners recommend sticking with either the genuine OEM part or a premium aftermarket brand known for quality, like Standard Ignition or Beck Arnley, to ensure reliability. Some forum discussions note that while aftermarket sensors can be a good value, a faulty one can cause significant diagnostic headaches.

Cost of Replacing Your I35 Oil Pressure Switch

The cost to replace the oil pressure switch is relatively low, especially if you do the work yourself. The part itself is inexpensive, and labor is minimal for an experienced mechanic.

Part/Service Estimated Cost
New OEM Switch $20 - $35
New Aftermarket Switch $13.55 - $42.08
Shop Labor $70 - $140
DIY Total (Aftermarket Part) $13.55 - $42.08
Shop Total (Aftermarket Part) $84 - $182

Frequently Asked Questions (FAQ)

Where is the oil pressure switch located on a 2002-2004 INFINITI I35?

The oil pressure switch on the VQ35DE engine in your I35 is located on the engine block, typically near the oil filter and oil pan. You will need to raise the front of the vehicle to access it from underneath. It is a small sensor with a single electrical connector.

Can I replace the I35 oil pressure switch myself?

Yes, this is a very feasible DIY job for most home mechanics. It requires basic tools, including a deep socket (often 27mm or 1 1/16"), a ratchet, and jack stands. The process involves raising the car, disconnecting the electrical connector, unscrewing the old switch, and installing the new one. A small amount of oil will leak out, so have a drain pan ready.

Are there any recalls or TSBs for the I35 oil pressure switch?

Searches of NHTSA data and TSB databases did not reveal any specific recalls or Technical Service Bulletins for the engine oil pressure switch on the 2002-2004 INFINITI I35. Recalls found for this vehicle range were related to the Takata airbag inflators.

Do I need to use thread sealant on the new switch?

Many new switches come with a pre-applied thread sealant. If yours does not, it is highly recommended to apply a small amount of automotive thread sealant or Teflon tape to the threads before installation to prevent leaks. Do not overtighten the switch; the torque specification is low, around 11-13 ft-lbs.

Technical Specifications

OEM Part Numbers: 25240-8996E 25240-89960 25240-89920 25240-89915 25240-4M40E 25240-4M400

Location: Engine block, near oil filter. Socket Size: Typically 27mm or 1 1/16 inch deep socket. Electrical Connector: Single pin.

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Apr 19, 2026

The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

Year Coverage
This article covers the Engine Oil Pressure Switch for:
  • INFINITI I35: 200220032004
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