Up for sale is a genuine VDO original equipment manufacturer (OEM) replacement electric temperature sending unit, engineered to provide precise fluid tracking and long-term diagnostic reliability. Rated for a maximum temperature of 250°F (120°C), this premium sensor monitors engine coolant, water, or oil temperatures in automotive, marine, and commercial machinery applications. It is calibrated with a factory-spec 287.4 to 22.7 ohm resistance curve to communicate seamlessly with VDO cockpit and instrumentation gauges, delivering exact cockpit readouts to protect your powertrain from unexpected overheating or component failures.

Key Features

Precision Matched Calibrations: Designed to work exclusively with VDO gauges matching a 250°F or 120°C maximum sweep scale on the dial face.
Rugged Industrial Build: Built inside an ISO and TSO registered manufacturing facility using heavy-duty, high-conductivity brass to survive severe engine block vibration.
Secure Knurled Nut Post: Outfitted with a classic knurled nut terminal system that locks your gauge signal wire securely to prevent connection slippage.
Self-Earthing Ground Structure: Features a standard ground path that completes the electrical circuit directly through the sender case into the metal framework of the engine.

Technical Specifications

Brand: VDO Instruments (Continental)
Part Number / MPN: 323-421D (Retail Boxed Variant of 323-421 / Bulk Part No. 323-421B)
Stamper Reference Number: V1531006073D (Component Reference No. 801/1/38)
Maximum Temperature Range: 250°F / 120°C
Ohmic Resistance Spectrum: 287.4 Ohms (Cold) to 22.7 Ohms (Hot)
Thread Size & Style: 3/8"-18 NPTF (Tapered Male)
Operating Voltage Range: Universal 6V to 24V DC Vehicle Platforms
Electrical Interface: Single Terminal Post with Knurled Thumb Nut
Warning Contact Alarm: No (Dedicated solely to variable gauge pointer modulation)

Installation Warning Note

No Thread Sealant Tapes: Because this sender relies entirely on physical metal-to-metal thread contact against the housing engine block to establish its electrical ground, do NOT wrap the threads in Teflon tape or use heavy liquid pipe dope. Applying insulative sealants will disrupt the standard ground loop, causing dead or highly erratic gauge readouts on your dashboard panel.

Please verify your dashboard gauge face range and matching engine port thread size prior to purchasing. Feel free to send a message if you have any questions!