Cooling System Pressure Test

This procedure performs a pressure test on the Rivian EDV 500's cooling system to identify leaks in the battery and motor cooling circuits.

Warnings

Tools required

Parts

• Cooling system O-rings and seals (as needed) × 1 — Use OEM specification
• Coolant reservoir cap (if damaged) × 1 — Use OEM specification

Fluids

• EV Battery/Motor Coolant — 10 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Ensure vehicle has been off for at least 2 hours and cooling system is at ambient temperature
3. Connect scan tool and verify no active thermal management system faults
4. Place vehicle in service mode following manufacturer procedures
5. Disconnect 12V battery negative terminal and wait 10 minutes
6. Remove front underbody panels to access cooling system components
7. Place drain pan under vehicle
8. Document current coolant level and condition
9. Check coolant concentration with refractometer (should be 50/50 glycol/water mix)

Procedure

1. 1

   Access and Inspect Cooling System Components
   Remove necessary trim panels and covers to access the coolant reservoir, radiator, and cooling system hoses. Visually inspect all cooling system components for obvious signs of leakage, corrosion, or damage. Check hose connections, clamps, reservoir, and heat exchanger areas. Document any visible concerns with photos.
2. 2

   Verify System Temperature and Pressure
   Use infrared thermometer to confirm cooling system components are at ambient temperature (below 100°F). Check coolant reservoir cap for proper sealing surface and inspect pressure relief valve operation. Verify reservoir is at proper cold fill level marking before testing.
3. 3

   Prepare Pressure Tester
   Select appropriate adapter for Rivian coolant reservoir from pressure tester kit. Ensure adapter O-rings are in good condition and lightly lubricate with coolant. Verify pressure tester gauge is functioning and calibrated (should read 0 PSI at atmospheric pressure). Set pressure relief on tester to maximum 25 PSI to prevent over-pressurization.
4. 4

   Install Pressure Tester to System
   Remove coolant reservoir cap completely. Install pressure tester adapter to reservoir neck, ensuring proper seal and thread engagement. Hand-tighten adapter securely but do not overtighten. Attach pressure tester pump assembly to adapter and verify all connections are secure.
5. 5

   Pressurize Battery Cooling Circuit
   Slowly pump pressure tester to bring system to 15 PSI. Monitor gauge for rapid pressure drop indicating major leak. Once at 15 PSI, stop pumping and observe gauge for 2 minutes. System should hold pressure within 1-2 PSI loss over this period. Record initial pressure and pressure after 2 minutes.
6. 6

   Visual Leak Inspection Under Pressure
   With system at 15 PSI, systematically inspect all cooling system components for leaks. Check battery pack cooling plate connections, motor cooling lines, reservoir, pump assembly, radiator, and all hose connections. Look for drips, wet spots, or coolant stains. Use UV dye and light if available for enhanced leak detection. Pay special attention to threaded connections and hose clamps.
7. 7

   Extended Pressure Hold Test
   Maintain system at 15 PSI and monitor for 15 minutes minimum. Acceptable pressure loss is no more than 2 PSI over 15 minutes in a sealed system. If pressure drops more than 2 PSI, continue visual inspection to locate source. Document pressure readings at 5, 10, and 15-minute intervals.
8. 8

   Check Internal Cooling Components
   While system is pressurized, check for coolant presence in areas where it should not be: inspect electric motor housings for coolant seepage through shaft seals, check battery pack drain ports for coolant, and verify no coolant in electrical connector areas. Use scan tool to check for moisture intrusion codes if equipped.
9. 9

   Test Motor Cooling Circuit Separately
   Release pressure from system by slowly opening tester relief valve. If vehicle has separate fill points for motor cooling circuit, repeat pressurization procedure on motor circuit to 15 PSI. Inspect motor cooling lines, heat exchanger connections, and motor cooling jackets for leaks. Hold pressure for 15 minutes and document results.
10. 10

    Pressure Cap Function Test
    Remove pressure tester from system. Using pressure tester cap adapter, test coolant reservoir cap pressure relief operation. Cap should hold pressure to rated specification (typically 15-18 PSI) then release smoothly. Replace cap if it releases prematurely or fails to release at proper pressure.
11. 11

    Release Pressure and Remove Tester
    Ensure all pressure is released from cooling system by opening tester relief valve completely. Verify gauge reads 0 PSI before removing tester. Carefully remove pressure tester adapter from reservoir. Inspect adapter O-ring for damage and clean any coolant residue from reservoir neck threads.
12. 12

    Top Off Coolant and Bleed System
    If coolant level dropped during testing, add EV Battery/Motor Coolant to proper cold fill level. Use coolant funnel with bleeder attachment if available. Do not overfill. Install reservoir cap and hand-tighten securely. If any connections were loosened during inspection, ensure they are properly retightened.
13. 13

    Clear Service Mode and System Verification
    Reconnect 12V battery negative terminal. Exit service mode using scan tool following manufacturer procedure. Start vehicle and allow thermal management system to run through self-test cycle. Monitor coolant temperature and circulation using scan tool. Verify no new fault codes are present.

Reassembly

1. Reinstall all underbody panels and trim pieces removed during access
2. Verify all fasteners are properly secured
3. Clean any spilled coolant from components and surrounding areas
4. Reset any thermal management system adaptations if required by manufacturer procedures

Verification

• Confirm no active cooling system fault codes present on scan tool
• Verify coolant level is at proper cold fill mark
• Run vehicle thermal management system and confirm proper operation through complete heating and cooling cycle
• Recheck all inspected areas for signs of leakage after thermal cycle
• Verify cooling system held minimum 13 PSI for 15 minutes during pressure test
• Document test results including pressure readings and any repairs performed
• Perform final visual inspection of all connections and components for proper installation

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