cooling

Radiator

for 2007 Ram 3500 5.9L I6 Cummins · 4WD

Difficulty

Moderate

Time

1.7 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 removal and installation of the radiator on a 2007 Ram 3500 with 5.9L Cummins diesel engine, including coolant drain, hose disconnection, and transmission cooler line removal.

Warnings

⚠️Never open cooling system when engine is hot. System operates under pressure and can cause severe burns.

⚠Coolant is toxic to animals and children. Clean all spills immediately and dispose of old coolant properly.

⚠Transmission fluid will drain from cooler lines when disconnected. Have drain pan ready and plug lines to prevent contamination.

ℹ️This diesel engine uses HOAT (Hybrid Organic Acid Technology) coolant. Do not mix with conventional green coolant.

Tools required

Drain pan (minimum 7 gallon capacity)Essential

Socket set (metric)Essential

Ratchet and extensionsEssential

Hose clamp pliersEssential

Flare nut wrench setEssential

Torque wrench (0-30 Nm range)Essential

Coolant funnel with adapter

Shop ragsEssential

Wire brush

Transmission line plug kit

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

Parts

Radiator assembly × 1 — Use OEM specification or quality aftermarket
Upper radiator hose × 1 — Replace if cracked or brittle
Lower radiator hose × 1 — Replace if cracked or brittle
Hose clamps (worm gear type) × 4 — Stainless steel preferred
Transmission cooler line O-rings × 2 — If equipped with quick-disconnect fittings
HOAT coolant concentrate × 14 — Mix 50/50 with distilled water

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 — 28 qt

Preparation

Ensure engine is completely cold to the touch (minimum 2 hours after shutdown)
Park vehicle on level ground and engage parking brake
Disconnect negative battery cable to prevent fan clutch engagement
Remove engine cover if equipped
Place large drain pan (minimum 7 gallon) under radiator drain petcock

Procedure

1
Drain cooling system
Slowly remove radiator cap by turning counterclockwise. Open drain petcock at bottom of radiator by turning counterclockwise. Allow coolant to drain completely into pan. Once drained, close petcock hand-tight to specification.
Torque spec
Drain Petcock5 Nm (4 lb-ft)
2
Remove upper radiator hose
Using hose clamp pliers, compress and slide clamps away from radiator neck and thermostat housing. Twist hose to break seal, then pull firmly to remove from both connections. Inspect hose for cracks or deterioration.
3
Remove lower radiator hose
Access lower hose from underneath vehicle. Compress and slide hose clamps away from radiator and water pump connections. Twist and pull hose to remove. Remaining coolant will drain from hose.
4
Disconnect transmission cooler lines
Locate transmission cooler lines on right side of radiator. Position drain pan under connections. Using flare nut wrench, loosen cooler line fittings at radiator. For quick-disconnect type, depress release tabs while pulling lines straight out. Immediately plug lines and radiator ports to prevent fluid loss and contamination.
⚠ATF will drain from cooler lines. Have rags ready and plug immediately to prevent contamination and fluid loss.
Torque spec
Transmission Cooler Lines25 Nm (18 lb-ft)
5
Disconnect fan shroud
Remove bolts securing upper fan shroud to radiator. Typically 4-6 bolts along top edge. Lift shroud upward and rest it on fan assembly - do not remove completely. This provides clearance for radiator removal without removing fan clutch.
6
Remove radiator mounting hardware
Remove the upper radiator mounting bracket bolts securing the radiator to the core support. Note that the radiator typically rests in lower rubber isolators rather than being bolted at the bottom. Note the position of any rubber isolators or spacers for reinstallation.
⚠Radiator mounts use plastic components. Do not overtighten on reassembly or mounts will crack.
Torque spec
Radiator Mount Bolts12 Nm (9 lb-ft)
7
Remove radiator from vehicle
Carefully lift radiator straight up and out of engine compartment. Tilt top toward engine slightly to clear fan shroud and fan blades. Watch for remaining coolant spillage. Inspect radiator mounting rubber isolators and replace if cracked or deteriorated.
8
Prepare and install new radiator
Transfer any reusable components from old radiator (petcock, mounting brackets if not included with new unit). Install rubber isolators in mounting positions. Verify transmission cooler fittings are correct type. If using quick-disconnect fittings, install new O-rings lubricated with ATF.
9
Install radiator into vehicle
Carefully lower new radiator into position, guiding it past fan shroud and into mounting locations. Ensure radiator seats properly on lower isolators and aligns with upper mounting holes. Install mounting bolts and torque to specification.
Torque spec
Radiator Mount Bolts12 Nm (9 lb-ft)
10
Reconnect transmission cooler lines
Remove plugs from radiator ports and transmission lines. For threaded fittings, thread lines by hand first to prevent cross-threading, then tighten to specification using flare nut wrench. For quick-disconnect type, push lines straight in until they click into place.
Torque spec
Transmission Cooler Lines25 Nm (18 lb-ft)
11
Reinstall radiator hoses
Clean radiator neck and engine connection points with wire brush. Install lower radiator hose first, ensuring it routes properly without kinks. Install new clamps and position 1/4 inch from hose end. Tighten clamps until snug and secure without crushing the hose. Repeat for upper hose.
Torque spec
Upper/Lower Hose Clamps3 Nm (2 lb-ft)
12
Reinstall fan shroud
Position upper fan shroud over fan assembly and align mounting holes with radiator. Install and tighten all shroud mounting bolts. Verify fan blades rotate freely without contacting the shroud at any point.
13
Fill cooling system
Mix HOAT coolant 50/50 with distilled water or use pre-mixed coolant. Slowly fill the cooling system through the coolant reservoir/degas bottle until full, allowing air to purge. Fill coolant reservoir to COLD MAX line. Install pressure cap. Start engine and allow to warm to operating temperature with heater on high to purge air from system, adding coolant as level drops.
14
Bleed cooling system and check for leaks
With engine at operating temperature, carefully remove radiator cap (use rag for protection). Add coolant as needed to bring level back to full. Reinstall cap. Check all hose connections, petcock, and transmission cooler lines for leaks. Rev engine to 2000 RPM several times while monitoring for leaks. Recheck coolant level when engine cools.

Reassembly

Verify all hose clamps are positioned correctly and torqued to specification
Double-check transmission cooler line connections for leaks
Ensure fan shroud is properly secured and fan has adequate clearance
Reconnect negative battery cable
Reinstall engine cover if equipped

Verification

Start engine and verify coolant circulation through radiator (upper hose should become hot)
Check heater output - should produce hot air when engine reaches operating temperature
Verify cooling fan engages at proper temperature (approximately 200-210°F)
Monitor coolant level in reservoir - should be at COLD line when cold, HOT line when at temperature
Inspect all connections for coolant or transmission fluid leaks after test drive
Check transmission fluid level after system has circulated and is at operating temperature
Monitor engine temperature gauge during test drive - should remain in normal range under load