Heater Hoses

Replace the heater hoses on a 2017 Maserati Levante 3.0L V6 Twin Turbo, including coolant drain, hose removal, and system refill with proper bleeding.

Warnings

Tools required

Parts

• Heater inlet hose × 1 — Use OEM specification
• Heater outlet hose × 1 — Use OEM specification
• Hose clamps (worm gear type) × 4 — 20-32mm range
• Coolant overflow reservoir cap O-ring × 1 — Use OEM specification

Fluids

• Maserati OAT Coolant — 10 qt

Preparation

1. Ensure engine is completely cold (minimum 2 hours after last operation)
2. Park vehicle on level surface and engage parking brake
3. Place protective fender covers over both front fenders
4. Disconnect negative battery terminal and wait 2 minutes for system power-down
5. Remove engine cover by lifting rear edge and pulling rearward to release clips
6. Remove upper plastic trim panels covering firewall area using trim tools
7. Position drain pan under radiator drain petcock location
8. Have replacement hoses and new clamps ready for installation

Procedure

1. 1

   Drain Cooling System
   Locate the radiator drain petcock on the lower driver side of the radiator. Slowly open the petcock and drain coolant into the drain pan. Once drained, close the petcock hand-tight to the specified torque. Remove the coolant reservoir cap to allow complete drainage.
   Torque spec

   Drain Petcock7 Nm (5 lb-ft)
2. 2

   Remove Coolant Reservoir
   Disconnect the electrical connector from the coolant level sensor on the reservoir. Remove the two mounting bolts securing the reservoir using a 10mm socket. Disconnect the coolant hoses from the reservoir by releasing the spring clamps with hose clamp pliers. Lift the reservoir out of the engine bay.
   Torque spec

   Mounting Bolts28 Nm (21 lb-ft)
3. 3

   Access Heater Hoses at Firewall
   Working from the passenger side of the engine bay, locate the two heater hoses where they pass through the firewall. These are typically 5/8-inch and 3/4-inch diameter hoses with worm gear clamps. Use a trim tool to carefully push aside any wire harnesses or vacuum lines for better access.
   ⚠The brake master cylinder is directly above this area. Do not allow tools or parts to contact brake lines.
4. 4

   Remove Heater Hose Clamps at Firewall
   Using hose clamp pliers or a flathead screwdriver, loosen the worm gear clamps at both heater hose connections at the firewall. Slide the clamps back along the hoses at least 2 inches away from the connection points. Note the orientation and position of each clamp for reinstallation.
5. 5

   Disconnect Heater Hoses at Firewall
   Twist each heater hose gently while pulling away from the firewall connection. If hoses are stuck, use a hose pick tool to carefully break the seal between the hose and nipple. Allow remaining coolant to drain into shop towels. Mark the upper and lower hose positions with tape or marker for reference.
   ℹ️Expect approximately 1-2 cups of coolant to drain from each hose connection.
6. 6

   Access Engine-Side Heater Connections
   Trace the heater hoses from the firewall back to their connection points on the engine. On the 3.0L V6 Twin Turbo, these connect to the thermostat housing and water pump outlet on the rear of the engine. Access is from above and requires reaching down behind the engine block.
7. 7

   Remove Engine-Side Hose Clamps
   Loosen the hose clamps at the thermostat housing and water pump connections. Slide the clamps back along the hoses. On the tight engine side, you may need to use a long extension with a flathead bit to access the clamp screws.
8. 8

   Remove Old Heater Hoses
   Twist and pull the heater hoses from the engine connections. If stuck, carefully use a hose pick to break the seal without damaging the metal nipples. Extract the hoses from the engine bay by carefully threading them past obstructions. Inspect the metal connection nipples for corrosion or damage.
   ⚠Do not use excessive force or metal tools on the thermostat housing nipples as they are aluminum and can be damaged.
9. 9

   Prepare New Heater Hoses
   Compare new heater hoses to the old ones to verify correct length and diameter. Slide new worm gear clamps onto each end of both new hoses in the correct orientation (screw head accessible after installation). Apply a thin film of coolant to the inside diameter of each hose end for easier installation.
10. 10

    Install New Heater Hoses at Engine
    Route the new heater hoses through the engine bay following the same path as the originals. Push the hoses firmly onto the thermostat housing and water pump nipples until they bottom out on the beads. Ensure hoses are fully seated with at least 1 inch of overlap on the nipples. Position the clamps over the connection points and tighten to specification.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
11. 11

    Connect Heater Hoses at Firewall
    Push the other ends of the heater hoses firmly onto the firewall nipples, ensuring they seat fully against the stops. Position the hose clamps 1/4 inch back from the hose ends and tighten to specification. Verify all four clamp connections are secure and positioned correctly.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
12. 12

    Reinstall Coolant Reservoir
    Reconnect the coolant hoses to the reservoir with their spring clamps. Position the reservoir back in its mounting location and install the two mounting bolts. Torque the bolts to specification. Reconnect the coolant level sensor electrical connector.
    Torque spec

    Mounting Bolts28 Nm (21 lb-ft)
13. 13

    Refill and Bleed Cooling System
    Using a coolant funnel with air bleed adapter, slowly fill the cooling system with fresh Maserati OAT coolant. Fill until coolant reaches the cold fill line on the reservoir. Start the engine and allow it to reach operating temperature (thermostat opens at approximately 195°F). Monitor coolant level and add as needed while air bleeds out. Run heater on high to circulate coolant through heater core. Continue until no more air bubbles appear and coolant level stabilizes.
    ⚠The cooling system holds 10 quarts. Refilling too quickly will trap air pockets that can cause overheating.
14. 14

    Pressure Test and Final Inspection
    With engine at operating temperature, inspect all four heater hose connections for leaks. Check that heater is producing hot air inside the cabin. Allow engine to cool, then recheck coolant level and top off to cold fill line if needed. Reinstall all trim panels and engine covers removed during access.

Reassembly

1. Reinstall upper engine cover by aligning front clips and pressing down firmly until all clips engage
2. Reinstall firewall trim panels and secure all clips
3. Reconnect negative battery terminal and tighten securely
4. Clean any coolant spills from engine bay and undercarriage with water

Verification

• Start engine and verify no coolant leaks at any of the four heater hose connections
• Confirm heater produces hot air when set to maximum temperature
• Verify coolant level is at cold fill line on reservoir when engine is cold
• Check for proper coolant circulation by feeling both heater hoses at firewall - both should be hot when engine is at operating temperature
• Scan for any diagnostic trouble codes related to coolant temperature or level sensors
• Test drive vehicle and monitor temperature gauge for normal operation (center position)

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