How to Replace Radiator Hoses on a Chevy 5.3 Liter Vortec V8 Engine

Your Chevy Avalanche’s radiator hoses are key parts of the cooling system, with an upper and a lower hose. The upper radiator hose carries warm coolant to the radiator to be cooled, while the lower radiator hose connects to the water pump, sending coolant back into the engine to keep your truck running cool. Replacing worn or failing radiator hoses on your 2003 Chevy Avalanche is an easy repair that can help ensure your truck’s cooling system is performing properly. If you need to replace your truck’s radiator hoses, you may see cracked, split, dry, leaking, or collapsed radiator hoses, a lack of coolant movement, or you might notice a coolant leak around the radiator hose clamps. When installing new radiator hoses on your Avalanche, it’s usually recommended that the hose clamps also be inspected, and in most cases, to use new hose clamps to ensure a complete repair. Failing or malfunctioning radiator hoses can result in a coolant leak, which may lead to your truck overheating or can cause engine failure. Our detailed, step-by-step instructions will help you perform a radiator hose replacement on your Chevy Avalanche.

Additional Resources

Tools & Materials

Safety Glasses Safety Glasses

Protective Gloves Nitrile Gloves 

Drip & Drain Pan Drain Pan

Radiator Hose Radiator Hose

ratchet Ratchets

Sockets for changing spark plugs Sockets

Shop Towels Shop Towels

Step-by-Step Instructions to Change Your Radiator Hoses on Your Chevy Avalanche

Today, we’ll be installing a radiator hose on this 2003 Chevy Avalanche 1500, but this process will be similar on a lot of Chevy Vortec V8s. A good number of GM and Chevy trucks were equipped with this engine, but be sure to know the specifics for your truck before getting started. And if you’re not completely comfortable doing this yourself, we’d be happy to recommend a professional technician in your area.

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How to Prepare Your Vehicle

Man removing cable from negative battery terminal

Step 1: Let Vehicle Cool and Disconnect Battery

Start by parking on a level surface and opening your hood. Let your vehicle cool, then disconnect the negative battery cable.
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Mechanic in blue gloves using shop towel to loosen and remove surge tank cap

Step 2: Slowly Remove Surge Tank Cap

Slowly rotate the surge tank fill cap counterclockwise. Stop rotating and allow the hissing to stop. After all hissing stops, continue turning counterclockwise to remove the cap.
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Man sliding drain pan under Chevy Avalanche

Step 3: Position Drain Pan Under Vehicle

Put the drain pan under the vehicle to catch any fluids from the engine.
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Man under vehicle using hand to loosen valve and fluid draining into drain pan

Step 4: Open Petcock and Drain Completely

Once the drain pan is in place, open the petcock and allow the system to drain completely. Once drained, close the radiator petcock.
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Mechanic using a ratchet to remove engine cover

Step 5: Remove Engine Cover

Take off the engine cover by loosening the intake manifold sight bolt shield and remove the cover from the cover retainer. Remove the cover retainer bolts and the retainer, if required.
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Man removing engine retainer from Chevy Avalanche

Step 6: Remove Air Cleaner Outlet Duct

Loosen the air cleaner outlet duct clamps at the throttle body and mass airflow/intake air temperature sensor. Then remove the radiator inlet hose clip from the outlet duct. Finally, remove the air cleaner outlet duct.
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Remove the Radiator Hose

Mechanic using screwdriver to remove clips and man pulling away hose from housing.

Step 7: Detach Radiator Vent Inlet Hose

Detach the radiator vent inlet hose from the radiator hose clips. Loosen the inlet hose clamp and remove the inlet hose from the radiator.
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Mechanic using pliers to remove a hose

Step 8: Detach Inlet Hose Clamp from Water Outlet

Detach the inlet hose clamp from the water outlet.
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Mechanic holding old upper radiator hose

Step 9: Remove Upper Radiator Hose

Remove the inlet hose clip from the fan shroud and remove the hose.
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Man using pliers to remove the lower radiator hose

Step 10: Remove Lower Radiator Hose from Water Pump Inlet

Remove the clamps to disconnect the lower radiator hose from the water pump inlet.
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Man using pliers to remove clamp from radiator hose

Step 11: Remove Lower Radiator Hose from Water Pump Outlet

Remove the clamps to disconnect the lower radiator hose from the water pump outlet.
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Mechanic using pliers to remove clamps from both radiator hoses

Step 12: Transfer Old Clamps to New Radiator Hoses

Now is a good time to transfer the clips from your old radiator hose to your new one.
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Install the New Radiator Hose

Man holding new radiator hose to water outlet and securing clamp with pliers

Step 13: Secure New Radiator Hose to Water Outlet

Secure the new hose to the water outlet using the hose clamp. Install the inlet hose clip to the fan shr
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Mechanic securing radiator hose in place with pliers

Step 14: Attach and Secure Hose to Radiator

Use the hose clamp to attach the hose to the radiator and attach the radiator vent inlet hose with the radiator inlet hose clips.
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Man installing new lower radiator hose to water pump

Step 15: Secure Lower Radiator Hose to Water Pump Inlet

Place the new lower radiator hose at the water pump inlet and secure it with the hose clamp.
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Mechanic in blue gloves using pliers to tighten hose clamp

Step 16: Secure Lower Radiator Hose to Water Pump Outlet

After securing the hose to the water pump inlet, place the new lower radiator hose at the water pump outlet and secure it with the hose clamp.
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Finishing Steps

Mechanic installing cover retainer on Chevy Avalanche

Step 17: Reinstall Air Cleaner Outlet Duct 

Install the air cleaner outlet duct. Tighten the air cleaner outlet duct clamps at the throttle body and MAF/IAT sensor to 62 inch pounds.



Do It Right: Be sure the arrow at the throttle body end of the duct is in alignment with the throttle body attaching stud.

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Vortex V8 engine cover being installed

Step 18: Reinstall Engine Cover

Install the engine cover retainer by putting it in place and securing it with the retainer bolts, if required. Tighten the bolts to 44 inch pounds. Install the engine cover.



Do It Right: Don’t let the cover contact the manifold absolute pressure sensor wire harness connector. 

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Man pouring O’Reilly Auto Parts Coolant into vehicle

Step 19: Refill Cooling System

Refill the cooling system, and reinstall the reservoir cap. Be sure to follow your vehicle manufacturer's specifications for coolant, type, ratio and fill procedure.
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Man reconnecting battery cable to battery

Step 20: Reconnect the Battery Cable

Reconnect your negative battery cable. Start your vehicle, and let it warm up to operating temperature with the heater on. If the heater is blowing warm air, turn the truck off and check the coolant level. Add coolant as needed, then close the hood. Before moving your vehicle, make sure to remove the drain pan from under your vehicle.
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Additional Resources

How to Do a Coolant Flush

How to Flush and Fill Your Antifreeze
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What is Leaking from My Car, Truck, or SUV?
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How to Install an Air Filter on a Ford F-150

These step-by-step instructions and video detail radiator hose replacement on a 2003 Chevy Avalanche 1500, and will be similar to replacement procedures on 1999, 2000, 2001, 2002, 2003, 2004, 2005, and 2006 Chevy Avalanche and Chevy Suburban 1500, 2500, and 3500 models. The replacement procedures will also be similar for select Chevy Tahoe models from 2000, 2001, 2002, 2003, 2004, 2005, and 2006, as well as Cadillac Escalade models from 2002, 2003, 2004, 2005, 2006, 2007, 2008, and 2009. Replacing damaged or failing radiator hoses helps you maintain a safe and functioning cooling system, and can keep your truck running cool. If you notice your truck’s radiator hoses are dry, splitting, or collapsed, or if you notice a coolant leak, you should repair your radiator hoses as soon as possible to prevent low coolant levels, which can lead to overheating and engine failure. Easily replace worn radiator hoses to keep your truck running cool.

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The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.