EV Coolant Manifold & Valve Block RFQ Checklist

# EV Coolant Manifold and Thermal Valve Block RFQ Checklist

EV thermal-management systems are becoming more integrated. Instead of isolated hoses, pumps, valves, brackets, and simple blocks, many platforms now combine coolant routing, electric pumps, valves, sensors, control electronics, and refrigerant/coolant interfaces into compact modules.

That trend creates a strong sourcing opportunity for aluminum coolant manifolds, thermal valve blocks, pump housings, valve housings, and machined port blocks. It also raises RFQ risk: a drawing may look like "just a manifold," but quote quality depends on ports, flow paths, O-ring grooves, sealing faces, cleanliness, leak testing, datum control, and assembly interfaces.

This checklist is for EV thermal engineers, procurement teams, supplier quality engineers, and module buyers preparing an RFQ for an EV coolant manifold, thermal valve block, integrated thermal-management housing, or aluminum coolant-routing component.

For related Bohua paths, review the valve body manufacturer page, pump housing manufacturer page, leak-tight aluminum casting hub, quality control page, and formal RFQ form.

Why coolant manifolds are a high-intent RFQ topic

Infineon describes integrated thermal-management systems as consolidating electric pumps and coolant valves into a centralized unit. TI Fluid Systems describes an integrated thermal manifold that combines coolant flow with mechatronics and integrates pumps, sensors, and valves. Hanon Systems describes coolant control modules with pumps, valves, customized connections, and optimized manifold designs.

For sourcing, that means the aluminum part is no longer a simple block. It may carry several circuits, seals, ports, mounting interfaces, sensor bosses, and assembly datums. If the RFQ does not define those boundaries, suppliers will quote different work.

Define the module boundary first

Start the RFQ by explaining what the aluminum part does in the thermal system.

State whether it is:

• •a coolant manifold
• •a thermal valve block
• •a pump housing or pump interface plate
• •a combined manifold and sensor block
• •a housing for an integrated thermal-management module
• •a machined casting that interfaces with plastic, rubber, tube, or electronic subassemblies

Also state whether the supplier is responsible for casting only, casting plus CNC machining, leak testing, coating, cleaning, assembly, inserts, plugs, or packaged subassembly delivery.

Map every port and seal

Coolant manifolds fail in the details: mislabeled ports, unclear O-ring grooves, poor sealing-land control, cross-leak paths, or thread assumptions that differ between suppliers.

Your RFQ should include:

• •port name and function: inlet, outlet, bypass, drain, vent, sensor, pump, valve, or plugged port
• •thread or connector standard
• •O-ring groove geometry and standard if specified
• •sealing-land flatness and surface finish
• •plug type and retention method
• •whether ports are cast, cored, drilled, machined, tapped, or assembled
• •cross-leak requirements between circuits
• •orientation requirements for vehicle packaging

If the buyer owns a coolant schematic, attach a simplified version with confidential details removed if needed.

Identify leak-test boundaries

A manifold can pass a single external leak test and still fail a cross-leak requirement between internal passages. Separate the leak-test boundaries in the RFQ.

Define:

• •external leak test boundary
• •internal cross-leak test boundary
• •blocked ports during test
• •test sequence before and after machining
• •test pressure, hold time, and acceptance criterion
• •coolant medium or air/helium method
• •fixture responsibility
• •whether test records are per part, per cavity, per lot, or per sample

For high-risk passages, ask suppliers to describe how they will seal threaded ports and O-ring faces during the test. That reveals whether the quote includes real fixture planning.

Make CMM datums visible

EV coolant manifolds and valve blocks often attach to pumps, valves, brackets, tubes, or electronic housings. A quote can be wrong if the supplier does not understand the datum structure.

Mark:

• •primary mounting face
• •pump or valve interface face
• •sensor boss datum
• •port centerline requirements
• •O-ring groove position
• •sealing-face flatness
• •critical thread position
• •bracket or vehicle assembly datums
• •machining stock and cast datum strategy

Ask for first-sample CMM reporting on the features that control assembly, not every noncritical wall.

Add cleanliness and burr requirements

Coolant manifolds are fluid-path parts. Chips, burrs, sand, blasting media, or coating flakes can damage pumps, valves, or sensors. The RFQ should state the cleanliness expectation before price comparison.

Include:

• •deburring requirement for ports and cross holes
• •no loose chips in coolant passages
• •washing or flushing expectation
• •particle-size limit if the buyer has one
• •packaging to prevent contamination
• •whether plugs or protective caps are required
• •whether cleanliness records are needed for samples or production

If no formal cleanliness spec exists yet, ask the supplier to propose a practical cleaning and packaging plan.

Clarify material, coating, and galvanic risk

Thermal-management manifolds may connect aluminum, plastic, steel inserts, brass fittings, rubber seals, and coolant chemistry. State:

• •alloy and acceptable equivalents
• •heat treatment if required
• •coating or conversion layer
• •corrosion-test requirement if specified
• •insert material and isolation requirement
• •fastener material
• •coolant chemistry and expected temperature range
• •whether the part contacts refrigerant-side components or only coolant-side components

Do not assume one coating works for every coolant. The buyer's material and validation standard should govern.

Ask for a supplier response matrix

Use this table in the RFQ so quotes can be compared:

This prevents a low quote from excluding fixtures, plugs, leak testing, cleaning, or inspection records.

What to send Bohua for review

For an EV coolant manifold or thermal valve block RFQ, send:

• •2D drawing with revision status
• •STEP or IGES model
• •coolant schematic or port map
• •annual volume, pilot quantity, and launch timing
• •alloy, heat treatment, coating, and coolant compatibility requirements
• •thread standards, O-ring groove details, and sealing-face requirements
• •leak-test requirements for external and internal circuits
• •cleanliness, burr, and packaging requirements
• •CMM datum plan and critical features
• •required records for samples, PPAP, FAI, or production release

If the part is drawing-ready, use the formal RFQ form. If the design is still under NDA discussion, start with the contact page.

Sources used for this RFQ guide

• •Infineon automotive integrated thermal management system
• •TI Fluid Systems ITMA integrated thermal manifold
• •Hanon Systems coolant control module and manifold design
• •Eaton liquid cooling solutions in electric vehicles

Bottom line

An EV coolant manifold RFQ should make the fluid path, sealing boundary, port map, leak-test logic, CMM datums, cleanliness requirement, and assembly interface visible before price comparison.

Bohua can review drawing fit for aluminum valve blocks, pump housings, coolant-routing castings, and machining-intensive thermal-management parts. Submit the RFQ package when the drawing, port map, and inspection scope are ready.