T-Pieces

A T-piece adds a branch to a hose run, so that a second line can join or leave the main one. The T-pieces here are one-piece silicone parts with three equal ports or a smaller side branch, a 90-degree T-bend, and 6061 aluminium T-pieces with a 25 mm branch.

In a cooling system, a branch typically feeds a heater, a turbo’s coolant supply or a bleed line to the expansion tank. Flow divides according to the resistance of each path, so a small branch off a large main line takes only a small share. A branch at a high point also gives trapped air a way out.

Silicone T-pieces are moulded in one piece, so there is no extra joint to leak. Aluminium T-pieces have a rigid spigot that cannot fold or kink, and they push inside the hose ends like a joiner.

Choose by main run and branch size:

• Equal T-pieces: three ports of the same size, such as 13, 19, 25 or 35 mm, in black or blue.
• Reduced-branch T-pieces: main runs from 32 to 70 mm with a 19 mm or 25 mm branch, such as 38 mm with 19 mm or 57 mm with 25 mm.
• T-bend: a 90-degree bend of 35 mm with a 19 mm branch, which turns a corner and adds a branch in one part.
• Aluminium T-pieces: 6061 parts in silver or black, with a 25 mm branch on main runs such as 35, 45, 60 and 76 mm.

Silicone T-pieces are sized by inside diameter and aluminium ones by outside diameter, so measure accordingly. Clamp all three joints, with a clamp sized for each port, and set the branch’s direction before tightening. Support the branch line so that its weight does not lever on the T.

After fitting a T-piece into a cooling system, refill and bleed out every air pocket, then check the joints for leaks once hot. Close a branch you do not need with a blanking cap of the right size, held with a clamp.