Catalog

HYUNDAI/KIA 971381H050 UNIT SUB-ASSY

HYUNDAI/KIA 971381H050 UNIT SUB-ASSY

Product Specifications

Product quality
OEM Equivalent Grade
starstarstar
Wholesale price USD $13.19
Wholesale price CNY ¥90
bolt MOQ (Minimal order)
19 pcs
local_shipping Production time
30-45 days
package_2 Shipping Weight: —
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HYUNDAI/KIA 971381H050
Overview & Operating Principle
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The UNIT SUB-ASSY is the heater core — a compact liquid-to-air heat exchanger mounted inside the HVAC housing behind the dashboard that transfers thermal energy from the engine's hot coolant circuit to the cabin airstream, providing cabin heating, windscreen demisting, and defrosting functions. The heater core operates as a small radiator in reverse — hot engine coolant at 75–90°C flows continuously through the core's aluminium or copper-brass tube matrix from the engine cooling circuit via the heater hoses, and the HVAC blower forces cabin air through the dense aluminium fin array; the temperature difference between the hot coolant and the cooler cabin air drives heat transfer through the tube walls and fins, warming the air delivered to the cabin to the temperature commanded by the climate control system. On vehicles with a manually operated temperature blend door, all of the blower's air passes through the heater core at all times and the blend door mixes a proportion of heated and unheated air to achieve the target cabin temperature; on electronically controlled systems the blend door position is determined by the climate control module. The heater core operates at coolant system pressure — typically 1.0–1.4 bar — and at continuous temperatures that cycle between ambient on cold starts and full operating temperature on sustained driving, imposing significant thermal fatigue on the tube-to-header joints over the vehicle's service life.

This unit — HYUNDAI/KIA 971381H050 — is manufactured to OEM-equivalent specifications: core external dimensions and fin-to-tube geometry for the HVAC housing mounting position, inlet and outlet pipe diameter and orientation for heater hose connection, core depth and fin pitch for the required heat transfer capacity at the rated coolant flow and blower airflow, and maximum pressure rating are matched to the original part. Supplied as a complete assembly ready for installation. Available wholesale from 13.19 USD, MOQ 19 pcs, production lead time 30-45 days.

Heater cores fail through tube-to-header joint fatigue cracking from decades of thermal cycling between ambient and operating temperature — the joint stress from differential thermal expansion between the tube material and the header casting accumulates until micro-cracks develop that allow coolant to seep into the HVAC housing and drip onto the passenger footwell carpet; through internal tube blockage from scale and corrosion deposits in degraded coolant that have been circulating for many years without a coolant change; and through external fin corrosion from the cabin air environment. A heater core leak inside the dashboard is particularly insidious because the coolant drips are often initially mistaken for a cabin air condensate leak, delaying diagnosis while the carpet sub-floor absorbs increasing coolant quantities — a sweet smell in the cabin and a fogged windscreen that cannot be cleared with the demist function are the diagnostic indicators that distinguish a heater core leak from condensate.

Symptoms & Diagnostics
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Sweet coolant smell in the cabin — particularly strong when the heater is switched on and the blower is running — coolant is leaking from the heater core into the HVAC housing and the airstream is carrying glycol vapour into the cabin; confirm by checking the passenger footwell carpet and the HVAC housing drain for coolant liquid; the sweet smell from ethylene glycol is distinctive and unmistakable — a sweet smell from the vents with a confirmed coolant level drop is diagnostic of a heater core leak until proven otherwise.
Windscreen that fogs on the interior surface immediately after the engine warms up, particularly in cold weather, and cannot be cleared with the demist function — coolant vapour from the leaking heater core is condensing on the cold windscreen glass in a fine oily film; this glycol condensate film is extremely difficult to clear with the blower and produces a characteristic rainbow sheen in direct sunlight; the inside of the windscreen feels slightly oily when touched at the area directly in front of the heater vents.
Wet carpet in the passenger footwell — a damp patch that does not correspond to wet weather or roof seal leakage — coolant from the leaking heater core is dripping from the HVAC housing onto the carpet and accumulating in the footwell; the coolant pool is often not visible because it has been absorbed by the carpet padding; press firmly on the centre of the footwell carpet and feel for liquid squeezing up; a distinct sweet smell from the wet area confirms coolant rather than condensate or rain water.
Reduced cabin heating performance — blower airflow is warm but not hot despite the engine at operating temperature and thermostat confirmed serviceable — the heater core tubes are partially blocked with scale or corrosion deposits that restrict coolant flow through the core; the core receives inadequate hot coolant flow and cannot transfer sufficient heat to the cabin airstream; confirm by feeling the temperature difference between the heater inlet and outlet hoses — both should be similarly hot; a cold outlet hose confirms blocked core flow.
Coolant level dropping progressively without any visible external leak — no puddle under the vehicle, no external coolant staining — the heater core leak is slow and the coolant is evaporating within the HVAC housing from the blower airflow before it reaches the carpet; the only indicator is the progressive coolant loss and the intermittent sweet smell in the cabin under certain airflow conditions; UV dye added to the coolant and UV lamp inspection of the HVAC housing interior confirms the source.
Oily or glycol-contaminated cabin air filter — the filter removed from the HVAC housing shows a sticky oily coating on its upstream face — coolant vapour has been passing through the filter from a slow heater core leak for an extended period; the saturated filter confirms the leak has been present for many weeks; inspect the HVAC housing interior for coolant staining and the footwell carpet sub-floor for hidden moisture accumulation.
Logistics & Customs
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International HS Code
8415.90
EAEU Customs Code (TN VED)
8415 90 000 0
Typical Net Weight
Country of Manufacture
China
Standard MOQ
19 pcs
Production Lead Time
30-45 days
Always verify the exact 8-digit or 10-digit subheading with your customs broker for the destination country, as tariff schedules and duty rates vary by jurisdiction.
Installation Tips
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  1. Drain the cooling system before disconnecting the heater hoses at the bulkhead — the heater circuit carries hot coolant at system pressure; draining to below the heater hose connection level prevents a coolant spill inside the cabin when the hoses are disconnected; place absorbent cloths under the hose connection points inside the engine bay and be prepared for residual coolant in the hoses when they are disconnected at the core stub pipes inside the dashboard.
  2. Remove the dashboard completely or access the HVAC housing through the passenger side partial dashboard removal — heater core replacement is one of the most labour-intensive repairs in passenger car service; on most modern vehicles the complete dashboard assembly must be unbolted and moved forward or removed entirely to access the HVAC housing; follow the vehicle-specific dashboard removal procedure precisely — improvised access attempts frequently result in dashboard trim cracking, airbag connector disturbance, and wiring harness damage that extend the repair significantly.
  3. Clean the HVAC housing interior thoroughly before installing the new heater core — coolant that has been leaking from the failed core will have coated the housing interior, the evaporator fins, and the blower scroll with a glycol film; this film must be removed with a warm water and mild detergent wash followed by drying before the new core is installed; a glycol-coated evaporator produces a persistent sweet smell in the cabin from the new core's first use that the owner will associate with a continuing fault.
  4. Replace both heater hose connection O-rings or rubber seals at the core stub pipes — the stub pipe seals are compressed single-use elements that cannot reseal reliably after the hoses are removed; a reused seal that does not seal completely produces a slow coolant seep inside the dashboard that is equally difficult to access as the original leak; always include new stub pipe seals in the parts order before beginning dashboard removal.
  5. Pressure-test the cooling circuit to 1.2 bar before refitting the dashboard — with the heater hoses reconnected and the system refilled, apply cooling system pressure and hold for 10 minutes while inspecting the new core connections inside the HVAC housing; this test confirms a leak-free installation before the dashboard is reassembled; discovering a leak after the dashboard is refitted requires a repeat full dashboard removal.
  6. Install the new UNIT SUB-ASSY (HYUNDAI/KIA 971381H050), reassemble the dashboard in reverse sequence confirming all electrical connectors are reconnected and all airbag system connectors are secured, refill and bleed the cooling system, run to operating temperature, confirm the cabin heats to the target temperature on all blend door positions, and confirm no sweet smell is detectable from any vent before returning the vehicle to service.
Tools: cooling system pressure tester, dashboard removal tool set, torque wrench for dashboard mounting bolts, absorbent cloths for coolant containment, warm water and detergent for HVAC housing cleaning, OBD-II scanner for airbag system fault code confirmation after reconnection.
Frequently Asked Questions
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Can a leaking heater core be temporarily bypassed rather than replaced, and what are the implications?
A heater core can be bypassed by connecting the two heater hoses together with a straight connector at the bulkhead, effectively removing the core from the coolant circuit without replacing it. This bypass eliminates the coolant leak immediately and prevents further cabin contamination, making it a valid temporary measure in an emergency or while awaiting parts. The implications are complete loss of cabin heating and windscreen demisting capability — the vehicle cannot be safely driven in cold or wet conditions where windscreen demisting is required for visibility. The bypass also slightly alters the coolant circuit's flow resistance, potentially affecting the thermostat's warm-up behaviour. Bypass should be considered only as a short-term measure until the replacement core is available; permanent bypass operation is not acceptable in cold climates where heating is a safety requirement. ok.parts supplies heater cores at wholesale MOQ from 13.19 USD per unit.
Is it worth flushing a partially blocked heater core before replacement, and what procedure is used?
Flushing a partially blocked heater core is worthwhile when the blockage has caused reduced heating performance without any coolant leak — a core that heats the cabin partially but not fully may have scale or deposit accumulation in the tubes that can be cleared. Disconnect both heater hoses at the bulkhead, connect a garden hose with moderate water pressure to the outlet pipe (to reverse-flush against the normal flow direction), and allow water to flow until it runs clear from the inlet pipe. Repeat with a proprietary radiator flush compound if the initial water flush is heavily discoloured. A core that restores near-full outlet flow after flushing can be returned to service; a core that does not respond to flushing, or that shows a coolant seep at any tube joint, requires replacement. Never use high-pressure compressed air to clear a heater core — the pressure surge can fracture the already-weakened tube-to-header joints.
How does the OEM-equivalent aftermarket unit compare to the genuine OEM part?
OEM-equivalent units in this catalogue replicate the current OEM design geometry and material specification. Quality is verified against OEM cross-reference data. When ordering in bulk, confirm with our team that the specification matches the latest OEM revision for your application.
Is white-label or custom packaging available for wholesale orders?
Yes. ok.parts works directly with the manufacturing facility and can accommodate neutral white-label packaging or fully branded packaging with your company logo, part numbers, and barcode. Minimum order quantities and lead times for custom packaging may differ from standard stock. Contact the team via the inquiry form to discuss your specific requirements.
Frequently Replaced Together
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PartReason for Combined Replacement
Heater Hoses
Inlet and outlet — application-specific length and diameter		The heater hoses are disconnected at both the bulkhead and the engine end during heater core replacement and should be inspected for internal hardening, swelling, and surface cracking simultaneously. Hoses that have been in service for the same period as the failed heater core may have internal delamination that restricts coolant flow or is close to failure. Replacing both heater hoses simultaneously with the core eliminates a repeat dashboard and engine bay access for a hose failure within a short interval.
Coolant (Engine Antifreeze)
OAT or HOAT per OEM specification		Heater core tube blockage from scale and corrosion deposits is caused by coolant that has depleted its corrosion inhibitor package and become acidic — the same chemistry that caused the original core blockage or accelerated the tube-to-header joint fatigue. Refilling with the same depleted coolant after core replacement immediately begins forming new deposits in the new core's tubes and continues to attack the joint chemistry. Always perform a complete coolant change with fresh coolant of the correct OEM specification simultaneously with heater core replacement.
Cabin Air Filter
Carbon combination filter recommended		A heater core that has been leaking into the HVAC housing will have contaminated the cabin air filter with glycol vapour — the filter will show a sticky oily coating and will retain the sweet coolant smell until it is replaced. Always replace the cabin filter simultaneously with the heater core; fitting a new core against a glycol-contaminated filter produces a persistent sweet smell from the vents that the owner will associate with a continuing core leak rather than the old filter.