HVCH Coolant Compatibility: An OEM Approval Checklist

HVCH coolant compatibility cannot be confirmed from a glycol percentage or an “EV coolant” label alone. Before releasing a high-voltage coolant heater into a bus or truck circuit, identify the exact fluid and obtain configuration-specific confirmation from the heater supplier and the vehicle’s thermal-system owner.

The review should cover the fluid formulation, concentration, dilution water, wetted materials and intended operating conditions. This checklist is for OEM engineering and procurement teams. It does not approve a coolant brand for an EVLINK heater or provide a universal conductivity limit.

Identify the fluid before comparing heater options

Give the supplier a product name, manufacturer, formulation or product code, current technical data sheet and safety data sheet. State whether it is supplied ready to use or mixed from concentrate. Record the intended concentration and whether the ratio is specified by volume or mass.

A safety data sheet supports handling and hazard review; it should not be treated as a component-compatibility certificate. Ask which approval documents or test evidence cover the proposed fluid in the selected heater assembly. Where only a generic fluid family is listed, request clarification before ordering the production configuration.

Glycol concentration is only one part of the specification

Two fluids described with the same glycol ratio need not have the same additive package or approval status. GLYSANTIN’s product-selection guidance emphasizes product-specific approvals and restrictions on mixing its different coolant technologies. That is a reason to check the exact formulation, not a basis for approving or rejecting every fluid from another manufacturer.

Document the required freeze protection alongside the heater’s operating envelope, pump and heat-exchanger requirements. Do not choose a concentration solely to improve one property, then assume the existing flow or heating validation still applies. Use the actual fluid data and the supplier’s approved conditions in the HVCH flow and pressure-drop review.

Do not equate an EV label with low conductivity

Different EV cooling architectures can call for different fluid characteristics. Arteco’s EV-OAT explanation specifically distinguishes that technology from applications requiring low or reduced electrical conductivity. A fluid being marketed for EVs therefore does not establish that it meets your circuit’s electrical requirements.

Ask the vehicle-system owner to define whether conductivity is controlled, the measurement conditions and the applicable acceptance evidence. Then ask the heater supplier to confirm compatibility with that exact fluid. Low conductivity is a fluid property, not permission to omit high-voltage isolation, protection or the vehicle’s electrical-safety validation.

Review the wetted assembly, not just a housing material

Request confirmation for the selected heater assembly, including its wetted metals, joints and seals where applicable. A generic statement that a fluid is suitable for aluminum does not establish approval for every assembled component in the loop. Include the pump, hoses, battery heat exchanger and other wetted components in the system-level review.

The following evidence requests help define what remains open:

• Which exact heater configuration and fluid formulation were assessed?
• What concentration, temperature exposure and other test conditions were used?
• Were relevant assembly materials and production processes represented?
• What inspection criteria, limitations and service conditions accompany the result?
• Who accepts the complete circuit, rather than only the heater component?

This is a suggested document-review checklist, not a prescribed test standard. Do not substitute a short warm-up run for missing compatibility evidence: it answers a different question from long-term material suitability.

Control dilution, filling and later fluid changes

Arteco’s water-quality guidance explains how ionic impurities can affect coolant conductivity and how unsuitable water can contribute to scale or corrosion. Its limits are product-specific; obtain the dilution-water requirements for the fluid you intend to use rather than transferring a number from another product.

For production and service planning, identify the approved fill product, mixing method where applicable, clean handling arrangements and permitted top-up procedure. Do not dilute a ready-mixed product unless its released instructions allow it. Keep records sufficient to distinguish a fluid change from a heater or control change during later investigation.

If a formulation, concentration or top-up fluid changes, ask the responsible suppliers which compatibility and performance evidence must be renewed. Agree the handling of residual old fluid and the approved flushing procedure before the change. Qualified staff must follow the vehicle’s isolation, cooling and fluid-handling procedures; this article is not a workshop drain-and-fill instruction.

Questions to settle before release

Can we approve a coolant because it has the same freeze point?

No. Freeze protection does not establish additive chemistry, material compatibility or the required electrical properties. Compare the full fluid specification and the component and vehicle approval evidence.

Does a low-conductivity fluid automatically work with our HVCH?

No. Ask for written confirmation for the exact heater configuration, formulation and operating conditions. Do not infer EVLINK approval from another heater manufacturer’s product description.

What if the fluid supplier changes the product?

Request the updated formulation identity and documents, identify the affected component approvals and agree the necessary revalidation before introducing it. Record who authorized the change and which configurations it covers.

Send a defined compatibility request to EVLINK

Start with the EVLINK high-voltage coolant heater range, then provide your intended heater configuration, exact coolant TDS/SDS, concentration, circuit layout, operating conditions and any conductivity requirements. State which vehicle-level approvals are already defined and which need clarification.

Send your heater and coolant specification for an engineering discussion. Request configuration-specific confirmation before treating a quotation, a product image or this general checklist as fluid-compatibility approval.