Gauge Mounting Accessories

Gauge mounting accessories put a sender where it reads accurately and a gauge where the driver can see it. This section holds aluminium hose adapters that give a temperature sender a threaded port, plain aluminium tube for rigid lines, and gauge holders shaped for particular cars.

A temperature sender must sit in moving coolant to read the true temperature. Where the engine has no spare port, a T-adapter cut into the hose gives the sender a boss in the flow. Fitted in the top hose near the engine outlet, it reads the hottest coolant in the circuit.

Single-wire senders complete their circuit through the thread. An aluminium adapter held between rubber hoses is insulated from the engine, so it needs an earth wire to the block, or the gauge will read wrongly.

Match the adapter to the hose and the sender:

• Hose size: T-adapters come in 26, 28, 30, 32, 34, 36 and 38 mm. Universal water temperature adapters come in 28, 30, 34 and 36 mm. Measure the inside diameter of the hose rather than trusting a part number.
• Sender thread: T-adapters take a 1/8 NPT or an M14x1.5 sender. NPT is tapered and seals on the thread, while M14x1.5 is parallel and seals on a washer.
• Finish: black or silver aluminium, to suit the engine bay.
• Tube: aluminium tube of 7.94, 9.5, 12.7 and 15.9 mm diameter in 2 m and 4 m lengths, for rigid lines.
• Gauge holders: ABS holders and cluster covers that take two 52 mm gauges, each shaped for the model named in the title.

Cut the hose on a straight section, push both ends fully onto the adapter and clamp them over its spigots. Point the sender boss sideways or down so no air gathers at the tip, then bleed the cooling system and check for leaks when hot. Re-tighten the clamps after the first heat cycles, as the rubber settles.

Seal NPT threads with a coolant-resistant sealant kept off the sender tip; a thick wrap of PTFE tape can also break the earth path. Bend aluminium tube with a proper bender to avoid kinks, finish the ends as the fittings require, and clip rigid lines so vibration cannot crack them.