cooling

Radiator Hoses - Both

for 2007 Ram 3500 5.9L I6 Cummins · 4WD

Difficulty

Easy

Time

1.8 h

Tools

Steps

✓Fact-checked. Built from OLP's spec database, then independently fact-checked line by line with every correction applied. Master-tech sign-off by Chris Hackleman is queued. Cross-check torque values against the factory manual, and stop if anything looks unsafe. How our data is made.

This procedure covers the replacement of both the upper and lower radiator hoses on a 2007 Ram 3500 with the 5.9L Cummins diesel engine, including coolant system draining and refilling.

Warnings

⚠️Never open the cooling system when the engine is hot. Pressurized coolant can cause severe burns. Allow engine to cool completely for at least 2 hours before beginning work.

⚠Coolant is toxic to animals and children. Clean up all spills immediately and dispose of old coolant properly at a recycling facility.

⚠The Cummins diesel engine has a high coolant capacity. Ensure you have adequate drain capacity and replacement coolant before beginning.

ℹ️This procedure will result in partial coolant loss. You do not need to drain the entire system, but have at least 4 quarts of HOAT coolant available for refilling.

Tools required

Drain pan (minimum 4 gallon capacity)Essential

Flathead screwdriverEssential

Hose clamp pliers or standard pliersEssential

FunnelEssential

Coolant hydrometer or refractometer

Razor blade or utility knife

Shop towelsEssential

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Parts

Upper radiator hose × 1 — Use OEM specification
Lower radiator hose × 1 — Use OEM specification
Hose clamps (if reusing old clamps is not possible) × 4 — Worm gear style, appropriate size

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Fluids

HOAT coolant 50/50 — 4 qt

Preparation

Ensure engine is completely cold to the touch
Park vehicle on level ground and engage parking brake
Place drain pan under radiator petcock location on passenger side lower radiator tank
Have replacement hoses and clamps ready for inspection before beginning removal

Procedure

1
Drain cooling system partially
Locate the radiator petcock on the passenger side lower corner of the radiator. Slowly open the petcock by turning counterclockwise to begin draining coolant into the drain pan. You only need to drain enough coolant to lower the level below the lower radiator hose connection (approximately 1-2 gallons). Once drained to appropriate level, close the petcock.
2
Remove upper radiator hose at radiator
Locate the upper radiator hose connection at the top of the radiator on the driver side. Use hose clamp pliers or standard pliers to compress and slide the hose clamp back approximately 2-3 inches away from the radiator neck. Twist the hose gently while pulling to break it free from the radiator neck. If the hose is stuck, use a razor blade to carefully slice along the length where it contacts the neck, being careful not to damage the radiator neck itself.
3
Remove upper radiator hose at thermostat housing
Follow the upper radiator hose to the thermostat housing located at the front top-center of the engine. Compress and slide back the hose clamp at this connection. Twist and pull the hose to remove it from the thermostat housing neck. Some residual coolant will drain, so have shop towels ready.
4
Remove lower radiator hose at radiator
Locate the lower radiator hose connection at the bottom passenger side of the radiator. Compress and slide the hose clamp back away from the radiator neck. Twist and pull the hose to remove it from the radiator. Expect some additional coolant drainage at this point.
5
Remove lower radiator hose at water pump
Trace the lower radiator hose to its connection point at the engine water pump on the front passenger side of the block. Compress and slide the hose clamp back. Twist and pull the hose to remove it from the water pump inlet. Remove the hose completely from the vehicle.
6
Inspect connection points
Thoroughly inspect all four connection points (radiator upper and lower necks, thermostat housing neck, and water pump inlet) for corrosion, cracks, or damage. Clean any debris or old rubber residue from the necks using a shop towel. If any necks show damage or excessive corrosion, the affected component should be replaced before installing new hoses.
7
Install new lower radiator hose
Place new hose clamps on the new lower radiator hose (one at each end), positioned approximately 1 inch from each end. Install the lower hose onto the water pump inlet first, pushing it on until it seats fully against the stop on the neck. Then install the other end onto the lower radiator neck, ensuring it is fully seated. Position clamps approximately 1/4 inch from the end of each neck and tighten securely. The clamps should be snug but not overtightened to avoid damaging the hose.
8
Install new upper radiator hose
Place new hose clamps on the new upper radiator hose. Install the hose onto the thermostat housing neck first, ensuring it seats completely. Route the hose to the upper radiator neck and install, pushing it on until fully seated. Position and tighten both clamps approximately 1/4 inch from the end of each neck. Ensure the hose routing does not contact any sharp edges or moving components.
9
Refill cooling system
Using a funnel, pour HOAT 50/50 coolant mixture into the radiator fill neck until the level reaches the bottom of the fill neck. Then fill the coolant overflow reservoir to the COLD MAX line. Do not overfill. Add coolant as needed to match the volume drained, then add more as needed during the bleeding process.
10
Bleed cooling system and check for leaks
With the radiator cap still off, start the engine and allow it to idle. Watch the coolant level in the radiator and add coolant as needed as air bleeds from the system. The level will drop as air escapes and the thermostat opens. Run the engine until the thermostat opens (coolant will begin circulating visibly and the upper hose will become hot). During this process, carefully inspect all four hose connections for any signs of leakage. Once the thermostat has opened and no air bubbles are visible, shut off the engine.
11
Final fill and cap installation
After the engine has cooled for 10-15 minutes, top off the radiator to the bottom of the fill neck if needed. Install the radiator cap securely. Check the overflow reservoir and fill to the COLD MAX line. Wipe down all connections with a clean shop towel to remove any spilled coolant, making future leak detection easier.

Reassembly

Ensure all hose clamps are positioned properly and tightened securely
Verify radiator petcock is fully closed and not leaking
Double-check coolant level in both radiator and overflow reservoir

Verification

Start the engine and bring to operating temperature while monitoring the temperature gauge for normal operation
Inspect all four hose connections for any signs of coolant leakage while engine is at operating temperature
Check for proper heater operation inside the cab, confirming coolant is circulating through the entire system
After the first drive cycle, recheck coolant level in the overflow reservoir when cold and top off if necessary
Monitor coolant level over the next few days to ensure no slow leaks have developed