Series 50 – Section 27.3 Faulty Pressure Control Cap

Section 27.3
Faulty Pressure Control Cap

To determine if a faulty pressure control cap is causing high engine coolant temperature, perform the following:‪

1. Perform coolant pressure control cap tests; refer to "4.4.2.1 Inspection of Pressure Control Cap" .
   1. If the cooling system pressure is less than or equal to 48.3 kPa (7 lb/in.² ), check the coolant hoses; refer to "27.4 Defective Coolant Hoses" .
   2. If the cooling system pressure is greater than 48.3 kPa (7 lb/in.² ), refer to "27.3.1 Pressure Control Cap Resolution" .

Section 27.3.1
Pressure Control Cap Resolution

Perform the following steps to resolve faulty pressure control cap:‪

1. Remove and replace pressure control cap; refer to "4.4.2 Cleaning and Removal of Pressure Control Cap" .
2. Install a new pressure control cap; refer to "4.4.3 Installation of Pressure Control Cap" .
3. Verify pressure control repair; refer to "27.3.1.1 Test Engine with Replaced Pressure Control Cap" .

Section 27.3.1.1
Test Engine with Replaced Pressure Control Cap

Perform the following to determine if exterior radiator repair resolved high engine coolant temperature: ‪

1. Start and run the engine.
2. Run the engine through its operating range with no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range.
   1. If the engine coolant temperature is normal, no further troubleshooting is required. Shut the engine down.
   2. If the engine coolant temperature is not normal, shut the engine down. Check coolant hoses; refer to "27.4 Defective Coolant Hoses" .