Formiden Engine Coolant Temperature Sensor G1852 12334869 with Pigtail Harness — Brass 1/2-14 NPT for Classic GM

This compact kit restores reliable coolant-temperature feedback to gauges or indicator lights on vintage Chevrolet, Buick, Pontiac, Oldsmobile and Cadillac models built roughly between the mid-1950s and late 1970s. The kit pairs a brass temperature sensor with a pre-wired pigtail connector so you can replace a brittle OEM plug and an aged sensor in one service. It’s an aftermarket replacement designed to match common GM part numbers and a 1/2"-14 NPT thread size for many applications.

Will this sensor fit my classic GM engine?

Compatibility is determined primarily by part number and thread specification. This kit cross-references numerous OEM numbers — including 12334869, 12334870, 1512678 and others — and uses a standard 1/2"-14 NPT thread that fits many intake manifold or cylinder head locations on older GM engines.

• Matches multiple OEM references such as G1852 and 12334869 for broad fitment.
• 1/2"-14 NPT thread common to many vintage GM engine ports.
• Intended for vehicles with gauge or warning-light temperature systems.
• Always verify by cross-referencing your vehicle’s factory part numbers.

How difficult is the installation and what tools are needed?

Installation is straightforward for anyone familiar with basic mechanical work but does require safety precautions. You’ll typically drain a small amount of coolant, remove the old sensor, apply thread sealant as needed, install the new sensor, and connect the included pigtail harness to the vehicle wiring.

• Common tools: wrench for 1/2"-14 NPT sensor removal, pliers, coolant catch pan.
• Use thread sealant or tape rated for coolant systems to prevent leaks.
• Allow the engine to cool fully before starting work to avoid burns.
• Consult a vehicle-specific manual for exact sensor location and torque specs.

What does the kit include and why replace the connector too?

The Formiden kit contains the brass temperature sensor and a matched pigtail harness with a new connector. Replacing the harness prevents problems from brittle, cracked factory plugs and avoids unreliable electrical connections that can cause erroneous gauge readings.

• 1 x replacement coolant temperature sensor (brass body).
• 1 x pre-assembled pigtail wiring harness with connector for a clean plug-in.
• Eliminates the need to splice aging OEM wiring or reuse fragile plastic housings.
• Supplies a ready-to-install solution for restoring accurate temperature signals.

Which classic GM models commonly use this sensor?

This part serves an extensive range of mid-century through 1970s GM cars and trucks. Typical applications include popular models from Chevrolet, GMC, Buick, Oldsmobile, Pontiac and Cadillac — especially V8-equipped cars and light trucks where the original sensor used similar threads and electrical connections.

• Chevrolet: Bel Air, Impala, Camaro, Corvette, Chevelle, C/K pickups.
• Buick: Electra, LeSabre, Riviera, Skylark, Regal (selected years).
• Oldsmobile & Pontiac: 98, Cutlass, Delta 88, GTO, Firebird, Grand Prix.
• Cadillac: DeVille, Eldorado, Fleetwood (selected 1960s–1970s models).

This aftermarket sensor provides a practical restoration part for owners and mechanics working on period-correct GM vehicles. It’s engineered to match common OEM references and the NPT thread used in many intake or head ports, but it's essential to confirm fitment by checking the part numbers and thread size for your exact vehicle before ordering.

Who is this for? Enthusiasts restoring classic GM cars or trucks, independent mechanics repairing vintage cooling systems, and anyone replacing a failed or brittle coolant sender plug will find this kit useful. It’s aimed at those who need a direct-fit replacement sensor and a reliable new pigtail connector to return accurate temperature signaling to a gauge or warning light system.