Brass water and coolant temperature sensor housings
Balford manufactures brass temperature sensor housings - the threaded thermo-wells that carry coolant, water, oil or air temperature sensors on engines, transmissions, heaters and industrial equipment. The housing is deep drawn or formed and then machined, so the thread, the sealing seat and the pocket for the sensing element are all held on the same part.
Why brass rather than stainless: a temperature sensor housing is a thermo-well. Brass conducts heat roughly ten times faster than stainless steel, so the element reacts sooner; it machines cleanly for threads and sealing faces; and it resists glycol coolant without a coating. Where the housing sees exhaust temperatures or aggressive chlorides, stainless takes over - Balford runs both materials in the same plant, so the choice is made on the application rather than on which supplier you already have.
What we make
| Part | Typical construction | Where it is used |
|---|---|---|
| Coolant temperature sensor housing | Brass body, machined thread and sealing seat, pocket for the element | Engine coolant circuits, thermostat housings |
| Water temperature sensor thermo-well | Brass tube closed at one end, threaded at the other | Heating and cooling systems, boilers, industrial water |
| Oil and air temperature housings | Brass or stainless body with machined ports | Engine oil, intake air, transmission |
| Brass fittings and adapters | Machined from bar, or formed and machined | Sensor installation into existing bosses |
| Stainless temperature housings | Deep drawn 304 / 316L shell with machined seat | Where chlorides, aggressive coolant or higher temperature rule brass out |
How a brass sensor housing is made
- Forming. The body is deep drawn from brass strip or turned from bar, depending on wall thickness, thread size and volume. Drawing is normally cheaper in volume; turning is normal for low volume and for large threads.
- Machining. The thread, the sealing seat and the element pocket are machined after forming. Machining the seat after forming is what keeps the seal concentric to the thread - the two characteristics that decide whether the housing seals.
- Threads. Metric, NPT, BSP and NPTF threads are cut and gauged with go / no-go gauges. The thread specification and the gauge to be used are agreed before tooling.
- Surface. Brass normally needs no plating. Where a specific finish is called for - nickel plating for appearance or wear - it goes through the same audited finishing network as our steel parts.
- Inspection. Thread gauging, sealing-face finish (Ra), concentricity between thread and seat, and a leak check where the customer requires one.
Materials and capacity
- Brass grades: C3604 / CuZn39Pb3, C3771 / CuZn40Pb2, C2600 / CuZn30, C2680 / CuZn37.
- Stainless alternative: 304 / 1.4301 and 316L / 1.4404, deep drawn up to Ø250 mm.
- Press capacity: 25 t to 350 t, with tooling designed and built in our own tool room.
- Documentation: first article inspection on a new tool, material certificates on request, PPAP Level 3 submissions, and IMDS material data where the customer needs it.
Frequently asked questions
Is a coolant temperature sensor housing brass or stainless steel?
Both are used, and the choice is made on the application. Brass conducts heat faster - about ten times faster than stainless - so it is preferred where the sensor has to respond quickly to a coolant or water temperature change. Stainless is preferred where chlorides, aggressive coolant chemistry or higher operating temperature rule brass out. Balford makes both.
Can the thread and the sealing seat be machined on a drawn brass housing?
Yes, and it normally should be. Forming sets the body; machining after forming sets the thread and the sealing face concentric to each other, which is what makes the joint seal. Both are gauged - the thread with go / no-go gauges, the face with a surface roughness tester.
Does a brass housing need plating?
Normally no. Brass resists the coolant environment on its own, so there is no coating thickness stacked on the wall tolerance. A nickel or other finish can be applied if appearance or wear resistance requires it.
What volume makes a drawn brass housing cheaper than a turned one?
It depends on wall thickness and thread size, but the crossover is usually in the low tens of thousands of parts per year. Below that, turning from bar is normally the cheaper route because it needs no tool. Balford quotes both and shows the crossover in the DFM review.