Coolant Flush

Complete coolant system drain, flush, and refill procedure for the 2015 Kia Forte 1.8L I4 engine, including bleeding to remove air pockets.

Warnings

Tools required

Parts

• Radiator drain plug washer × 1 — Use OEM specification
• Radiator hose clamps (if damaged) × 2 — Replace as needed

Fluids

• Hyundai/Kia Long Life Coolant (Green) — 7.5 qt

Preparation

1. Ensure engine is completely cold (wait minimum 2 hours after last operation)
2. Park vehicle on level ground and apply parking brake
3. Remove engine splash shield if equipped to access radiator drain plug
4. Open hood and locate radiator cap, coolant reservoir, and radiator drain plug on bottom passenger side of radiator
5. Place drain pan under radiator drain plug location

Procedure

1. 1

   Release cooling system pressure
   Slowly turn the radiator cap counterclockwise to the first detent and allow any residual pressure to escape. Wait until hissing stops completely, then remove cap fully. Remove coolant reservoir cap as well.
2. 2

   Drain coolant from radiator
   Position drain pan under radiator drain plug located at bottom passenger side of radiator. Remove drain plug completely and allow coolant to drain into pan. If equipped with petcock-style drain, open by turning counterclockwise. Allow system to drain for 10-15 minutes until flow stops.
3. 3

   Drain coolant from engine block
   Locate engine block drain plug on rear passenger side of engine block, below cylinder head. Position drain pan and remove drain plug. Allow block to drain completely for 5-10 minutes. This ensures all old coolant is removed from system.
4. 4

   Flush cooling system (optional but recommended)
   If performing full flush, reinstall radiator and block drain plugs hand-tight. Fill system with clean water through radiator neck. Start engine and run until thermostat opens (upper radiator hose becomes hot), then turn off. Allow to cool 30 minutes, then drain again. Repeat if draining coolant was heavily contaminated.
5. 5

   Reinstall drain plugs
   Install new washer on radiator drain plug. Thread drain plug into radiator by hand until seated, then torque to specification. Reinstall engine block drain plug to specification. Ensure both plugs are secure with no cross-threading.
   Torque spec

   Block Drain Plug25 Nm (18 lb-ft)
6. 6

   Fill cooling system with coolant mixture
   Using a funnel, slowly pour 50/50 premixed Hyundai/Kia Long Life Coolant (Green) into radiator neck until it reaches the base of the neck. Fill slowly to allow air to escape. Total system capacity is 7.5 quarts. Fill coolant reservoir to MAX line as well.
7. 7

   Bleed air from cooling system
   Locate coolant bleed screw on water outlet fitting (front of engine near thermostat housing). Loosen bleed screw 2-3 turns while continuing to add coolant to radiator. When solid coolant stream flows from bleed screw without air bubbles, tighten to specification. Top off radiator as needed.
   ℹ️Keep bleed screw open during initial fill to prevent air pocket formation in system.
   Torque spec

   Bleed Screw7 Nm (5 lb-ft)
8. 8

   Run engine to circulate coolant
   Install radiator cap securely. Start engine and allow to idle with heater set to maximum heat and fan on high. Monitor temperature gauge and watch for normal operating temperature. Run engine for 5-10 minutes until upper radiator hose becomes hot, indicating thermostat has opened.
   ⚠Monitor temperature gauge closely. If gauge approaches red zone, shut off engine immediately and allow to cool before investigating.
9. 9

   Perform final bleeding
   With engine at operating temperature and still running, carefully loosen bleed screw slightly. If air escapes, allow coolant to flow until bubble-free, then retighten to specification. Shut off engine and allow to cool for 15 minutes.
   Torque spec

   Bleed Screw7 Nm (5 lb-ft)
10. 10

    Check coolant level and top off
    Once engine has cooled slightly (but radiator cap is still warm), carefully remove radiator cap and check coolant level. Add coolant as needed to bring level to base of radiator neck. Check reservoir level and ensure it is at MAX line. Reinstall radiator cap securely.

Reassembly

1. Reinstall engine splash shield if removed
2. Wipe down any coolant spills from engine bay and radiator area
3. Dispose of old coolant properly at recycling center or auto parts store

Verification

• Start engine and verify no coolant leaks from drain plug, bleed screw, or hose connections
• Allow engine to reach operating temperature and verify heater blows hot air on both sides
• Check that temperature gauge remains in normal range during idle and does not fluctuate abnormally
• After first drive cycle (50-100 miles), recheck coolant level in reservoir when cold and top off if needed
• Monitor for any coolant loss or overheating symptoms over next few days of driving

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle