550-487 - Piper Aircraft OEM Rochester Oil Temperature Sender Probe

550-487 – Piper Aircraft OEM Rochester Oil Temperature Sender Probe

Available now on the Airparts.aero Marketplace.

Overview

The Piper Aircraft 550-487 is a genuine OEM oil temperature sender probe, a flight-critical sensor manufactured by Rochester Gauges for a vast range of Piper aircraft. This probe is an essential component of the engine monitoring system, designed to provide an accurate, reliable electrical signal that corresponds to the engine's lubricating oil temperature. The cockpit gauge uses this signal to display a real-time temperature reading, giving the pilot one of the most important indications of engine health. As a genuine Piper-specified part, it guarantees the correct resistance curve and physical fitment required for accurate instrumentation.

Key Features

• Variable Resistance Sensor: Functions as a thermistor, a type of resistor whose electrical resistance changes predictably with temperature. This provides a simple, reliable, and continuous signal to the cockpit gauge.
• High Thermal Conductivity: The probe's body is machined from solid brass. This material is chosen for its excellent thermal conductivity, which allows the internal sensing element to quickly and accurately respond to changes in oil temperature.
• Durable Construction: Engineered to withstand the harsh environment of the engine compartment, including constant vibration, high temperatures, and exposure to engine oil and other fluids.
• OEM Calibration: As the genuine OEM part, its resistance-to-temperature curve is perfectly calibrated to match the corresponding Piper-installed Rochester oil temperature gauge, ensuring the pilot sees an accurate temperature reading.
• Direct Fit Replacement: Designed with the correct thread size and electrical stud to be a direct, drop-in replacement for the original sender, ensuring a straightforward and airworthy installation.

Technical Specifications

• Part Number: 550-487
• Replaces OEM Part Number: 486-441
• OEM Manufacturer: Rochester Gauges, Inc.
• Component Type: Oil Temperature Sender Probe (Thermistor)
• Body Material: Brass
• Thread Specification: 5/8-18 UNF
• Electrical Connector: 8-32 Stud Terminal
• Primary Application: Engine Oil Temperature Measurement
• Certification: FAA Production Approval (when sourced as a Piper OEM part)

Aircraft Compatibility

The 550-487 is one of the most widely used oil temperature senders in the entire Piper Aircraft fleet, from classic tube-and-fabric aircraft to modern trainers and personal aircraft. It is imperative to consult the specific aircraft's Illustrated Parts Catalog (IPC) for final verification.

• Common Aircraft Models:
  • Piper J-3 Cub
  • Piper PA-11 Cub Special
  • Piper PA-18 Super Cub
  • Piper PA-20 Pacer / PA-22 Tri-Pacer
  • Piper PA-28 Cherokee, Warrior, Archer, Arrow
  • And many other Piper models.

Applications

The 550-487 is a critical sensor for the primary engine instrumentation:

• Engine Health Monitoring: Provides the pilot with a real-time oil temperature reading. Abnormally high temperatures can be the first indication of a problem such as low oil quantity, an impending bearing failure, or improper engine leaning.
• Engine Warm-up & Operation: Allows the pilot to confirm that the oil has reached a safe operating temperature before applying high power settings.
• System Troubleshooting: A key component to test when diagnosing an inoperative or inaccurate oil temperature gauge reading.

Why Choose 550-487?

An accurate oil temperature reading is essential for the safe and efficient operation of a piston engine. The Piper 550-487 is the genuine, factory-specified sender designed to work in perfect harmony with your aircraft's original gauge. Using a non-certified part can result in an inaccurate resistance curve, leading to dangerously misleading temperature indications in the cockpit. For a flight-critical instrument, there is no substitute for the guaranteed calibration, quality, and airworthiness of a genuine OEM component.

Order Your 550-487 Oil Temperature Sender Now

Ensure your engine instrumentation is accurate and reliable with a genuine Piper OEM sensor. Visit Airparts.aero to order your 550-487 oil temperature sender probe today.

The 550-487 oil temperature sender operates on the principle of a negative temperature coefficient (NTC) thermistor. The semiconductor material inside the probe has a high electrical resistance when it is cold. As the engine oil heats the probe, the resistance of the semiconductor material decreases in a precise, non-linear curve. The oil temperature gauge in the cockpit is essentially an ammeter calibrated to display temperature instead of current. As the sender's resistance drops, it allows more current to flow through the gauge circuit, causing the needle to deflect higher, indicating a higher temperature. The specific calibration of this resistance curve in the 550-487 is designed to match the calibration of the Piper-installed gauge.

Note: This is a flight-critical engine instrument sensor. Installation must be performed by a certified A&P mechanic. Use an appropriate thread sealant on the pipe threads to ensure a leak-proof seal. Do not overtighten, as this can damage the probe or the engine case. Verify a correct reading after installation.