How to Replace the Upper or Lower Radiator Hose on a 2018 Hyundai Elantra
Step-by-step hose swap with required tools/parts, coolant drain & refill, bleeding air, and leak checks
How to Replace the Upper or Lower Radiator Hose on a 2018 Hyundai Elantra
Step-by-step hose swap with required tools/parts, coolant drain & refill, bleeding air, and leak checks
🔧 Elantra - Radiator Hose Replacement
On your Elantra, radiator hoses carry coolant between the engine and radiator. Replacing a leaking/soft hose prevents overheating and coolant loss. Because there are multiple radiator hoses, the steps change depending on which one you’re replacing.
Difficulty Level: Intermediate | Estimated Time: 1.0–2.0 hours
⚠️ Safety & Precautions
- ⚠️ Never open the coolant cap on a hot engine; hot coolant can spray and burn.
- ⚠️ Support the car with jack stands before going underneath; never rely on a jack alone.
- ⚠️ Coolant is toxic; keep it away from kids/pets and clean spills immediately.
- 🔋 Battery disconnect is not required for this job, but keep tools away from the cooling fan area.
🔧 Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Nitrile gloves
- Floor jack (rated 2-ton minimum)
- Jack stands (rated 2-ton minimum)
- Wheel chocks
- Drain pan (at least 2-gallon)
- Pliers for spring clamps
- Hose clamp pliers (specialty)
- Flathead screwdriver
- 8mm socket
- 10mm socket
- Ratchet (3/8" drive)
- 3" extension (3/8" drive)
- Pick tool (specialty)
- Funnel
- Shop rags
- Torque wrench (3/8" drive)
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Radiator hose (upper or lower, as needed) - Qty: 1
- Hose clamps (OE-style spring clamps or worm-gear clamps) - Qty: 2
- Engine coolant (Hyundai/Kia compatible, phosphate-based) - Qty: 1–2 gallons (mix depends on product)
- Distilled water - Qty: 1 gallon
📋 Before You Begin
- Park on level ground, set the parking brake, and place wheel chocks behind the rear wheels.
- Let the engine cool completely (ideally overnight).
- Confirm which hose you’re replacing:
- Upper radiator hose runs from the top of the radiator to the engine/thermostat area.
- Lower radiator hose runs from the bottom of the radiator to the engine/water pump area and usually needs access from underneath.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Confirm hose type (upper vs lower)
- Open the hood and locate the hose you’re replacing.
- If you tell me “upper” or “lower,” I can tailor the exact access steps. If you want to proceed now, the steps below cover both paths.
Step 2: Relieve pressure safely
- With the engine cold, place shop rags around the coolant reservoir cap.
- Slowly loosen the cap to release any leftover pressure, then remove it.
Step 3: Raise the front (needed for lower hose and easier draining)
- Use a floor jack to lift the front of the car at the front center jack point.
- Set it securely on jack stands.
Step 4: Drain enough coolant to get below the hose level
- Place a drain pan under the radiator area.
- If equipped with an under cover, remove fasteners using a 10mm socket and ratchet.
- Open the radiator drain (petcock) if accessible by hand; if it’s tight, use an 8mm socket carefully (do not over-tighten plastic drains).
- Drain until the coolant level is below the hose you’re replacing, then close the drain snugly by hand.
- Tip: Drain less = less mess later.
Step 5: Remove the hose clamps
- At each end of the hose, compress the spring clamp using pliers for spring clamps or hose clamp pliers (specialty).
- Slide the clamp back a few inches onto the hose.
- If you have worm-gear clamps, loosen them with a flathead screwdriver.
- Tip: Take a photo before removing anything.
Step 6: Break the hose free (don’t yank)
- Twist the hose back and forth by hand to break it loose from the fitting.
- If it’s stuck, gently work the edge with a pick tool (specialty) to separate it from the nipple (the metal/plastic tube the hose sits on).
- Pull the hose off and aim it into the drain pan for any remaining coolant.
Step 7: Prep the fittings
- Use shop rags to wipe the radiator neck and engine-side fitting clean.
- Check for cracks on plastic radiator necks and corrosion on metal fittings.
Step 8: Install the new hose
- Put the clamps onto the new hose first.
- Push the hose fully onto each fitting until it seats against the stop/bead.
- Reposition clamps to the same location as original (usually just behind the raised bead on the fitting) using hose clamp pliers (specialty) or pliers for spring clamps.
- If using worm-gear clamps, tighten with a flathead screwdriver (snug; do not crush the hose).
Step 9: Reinstall any covers
- Reinstall the under cover using a 10mm socket, ratchet, and 3" extension.
- Torque to 8 Nm (71 in-lbs) for small under cover bolts if applicable.
Step 10: Refill coolant
- Use a funnel to refill the reservoir/radiator fill point with the correct coolant mix (typically 50/50 coolant and distilled water unless your coolant is premixed).
- Add coolant slowly to reduce air pockets.
Step 11: Bleed air from the cooling system
- Start the engine and set the heater to HOT with the fan on low.
- Let the engine idle until it reaches normal operating temperature; watch for the radiator fan to cycle on.
- As the thermostat opens, the coolant level may drop—top off as needed using the funnel.
- Squeeze the upper hose gently (with gloves) to help push air out.
- Install the reservoir cap once the level stabilizes.
✅ After Repair
- Check for leaks at both hose ends while idling and after a short drive.
- Verify the heater blows hot air (helps confirm coolant flow).
- After the engine cools fully, recheck the coolant level and top off if needed.
- Dispose of old coolant properly (never dump on the ground).
💰 DIY vs Shop Cost
Shop Cost: $200–$450 (parts + labor)
DIY Cost: $40–$120 (parts only)
You Save: $160–$330 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0–2.0 hours.
🎯 Ready to get started?
Quick question so I can tailor the exact access points on your Elantra: are you replacing the upper radiator hose or the lower radiator hose?
HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.


















