-12AN Port PLug x 5/8in -18 Temp-Port

The -12AN Port Plug x 5/8in -18 Temp-Port from Peterson Fluid is a precision adapter fitting engineered for high-performance cooling system installations where temperature monitoring or fluid bypass ports require a clean, leak-free connection. This straight-port adapter converts a 5/8-18 female thread to a -12 AN male O-ring boss configuration, making it essential for builders and technicians integrating aftermarket coolant lines, sensor ports, or bypass circuits into custom engine builds. The compact, lightweight design ensures compatibility with tight engine bay layouts without compromising flow integrity or reliability.

Machined from aluminum and finished in black anodize, this fitting delivers corrosion resistance and durability in both street and competition environments. The O-ring boss (-12 AN) male end provides superior sealing compared to traditional thread-seal methods, eliminating the need for PTFE tape and reducing installation time. The 5/8-18 female port accepts OEM and aftermarket temperature sensor adapters, gauge senders, and bypass fittings, while the straight-flow design minimizes turbulence and pressure drop—critical factors in maintaining consistent coolant flow rates and accurate temperature readings in modified cooling systems.

This adapter is ideal for street rod builders, drag racers, and performance engine tuners who require modular coolant system configurations. It's commonly used to integrate auxiliary water pumps, electric fan controllers, and transmission cooler circuits into existing -12 AN plumbing layouts. Installation is straightforward—thread the 5/8-18 end into the source port and seat the O-ring boss connection into your -12 AN manifold or distribution block using standard AN hardware. The 0.08 lb weight and compact 2.6 x 1.15 x 3 inch profile make it easy to route in confined spaces without adding bulk.