Content Source: 2020 PRO-RMK / RMK ASSAULT / SKS 155 Owner’s Manual (9929772 R02) > Maintenance Chapter

IMPORTANT

The Owner's Manual for this vehicle contains warnings, instructions and other information you must read and fully understand before safely riding or performing maintenance on this vehicle.Always follow the warnings and instructions in Owner's Manual.

Click the CONTENTS link above for the Table Of Contents, or download a full PDF of the Owner Manual in the Owner Support area of Polaris.com

Cooling System

Coolant

POLARIS recommends the use of POLARIS Antifreeze 50/50 Premix. This antifreeze is already premixed and ready to use. Do not dilute with water. If the vehicle will be stored or operated at extremely low temperatures, greater protection may be required. An authorized dealer can assist.
To ensure that the coolant maintains its ability to protect the engine, we recommend that the system be completely drained every five (5) years and fresh Antifreeze 50/50 Premix.
Any time the cooling system has been drained for maintenance or repair, replace the coolant with fresh Antifreeze 50/50 Premix.
NOTICE
If coolant flow becomes restricted or plugged, coolant loss, air lock, or engine damage may result. Most cooling systems are equipped with a filter that should be periodically inspected or replaced.

Coolant Level

The engine coolant level is controlled by the recovery system. The recovery system components are:
  • Coolant bottle/overflow tank
  • Pressure cap
  • Connecting hoses
  • In-bottle Thermostat (850 models only)
Always maintain the coolant level at or slightly above the FULL COLD mark on the coolant bottle (when the engine is cold).
  1. Stop the engine.
  2. Open the right side panel.
  3. View the coolant level in the coolant bottle. Add coolant as needed.
NOTICE
Operating the snowmobile with insufficient coolant will result in overheating and serious engine damage. Always maintain the coolant level as recommended.

Flushing the Cooling System

To ensure that the coolant maintains its ability to protect the engine, we recommend that the system be completely drained every five (5) years and fresh Antifreeze 50/50 Premix added. This service must be performed when the engine is cold. Your POLARIS dealer can check the coolant when performing the fall tune-up on your snowmobile.

Bleeding the Cooling System (600/800 Models)

WARNING
Steam and hot liquids will cause burns to your skin. Never bleed the cooling system or remove the pressure cap when the engine is warm or hot.
Use of a non-standard pressure cap will not allow the recovery system to function properly. If the pressure cap needs replacement, contact your dealer for the correct part.
NOTICE
Severe engine damage may occur if the cooling system becomes restricted or plugged or contains trapped air pockets.
Perform this procedure in a well-ventilated area. Use the recommended coolant. See Coolant.
  1. Open the side panels and remove the hood.
  2. Close the side panels.
    WARNING

    Never operate a snowmobile with the side panels open or removed.
  3. Position the snowmobile with the right ski and control arms elevated at a 45-degree angle.
  4. Fill the coolant bottle to the COLD FILL mark.
  5. Install the coolant bottle cap to the first lock. Do not tighten to the fully seated position.
  6. Lock the parking brake.
  7. Start the engine and allow it to run at a fast idle for several minutes, until the heaters are warm to the touch. Loosen the bleed screw occasionally to purge any trapped air.
  8. When all heater extrusions are warm to the touch, stop the engine.
  9. Allow the engine and cooling system to cool. Secure the bleed screw.
  10. Fill the coolant bottle to the COLD FILL mark. Reinstall the bottle cap securely.
  11. Carefully lower the front end of the snowmobile.
  12. Open the side panels and reinstall the hood. Close the side panels.

Bleeding the Cooling System (850 Models)

The cooling system is a self bleeding system.
caution
Cooling system under pressure. Steam and hot liquids will cause burns to your skin. Never bleed the cooling system or remove the pressure cap when the engine is warm or hot. Wear eye protection when servicing the cooling system.
NOTICE
Pressure cap rated at 13 PSI (0.9 BAR). Use of a non-standard pressure cap will not allow the recovery system to function properly.
caution
Perform this procedure in a well-ventilated area. Use the recommended 50/50 Extended-Life Antifreeze.
  1. Open the side panels and remove the hood.
  2. Close the side panels.
  3. Fill the coolant bottle to the COLD FILL mark.
  4. Install the coolant bottle cap to the first lock. Do not tighten to the fully seated position.
  5. Lock the parking brake.
  6. Start the engine and allow it to run at a fast idle for several minutes, until the heaters are warm to the touch.
    caution

    Keep the coolant level in the coolant bottle at or near the COLD FILL mark when engine is running. The engine may suck the coolant down quickly which my require coolant to be added a few times to stabilize the coolant level.

  7. When all heater extrusions are warm to the touch, stop the engine.
  8. Allow the engine and cooling system to cool.
  9. Fill the coolant bottle to the COLD FILL mark. Reinstall the bottle cap securely.
  10. Open the side panels and reinstall the hood. Close the side panels.

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