3512B Petroleum Engines Caterpillar

Illustration 1	g00286371
Typical Pressure Relief Valve System (1) Pressure relief valve. (2) Stud for filler cap.

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Steam or hot coolant can cause severe burns. Do not loosen the filler cap or the pressure cap on a hot engine. Allow the engine to cool before removing the filler cap or the pressure cap.

Note: The radiator is not supplied by Caterpillar. Refer to the manufacturer's instructions for details on testing the radiator for leakage.

Use the following procedure to check the pressure in the cooling system:

1. After the engine is cool, loosen the filler cap slowly and allow pressure out of the cooling system. Then remove the filler cap from the radiator.

2. Inspect the filler cap carefully. Look for damage to the seal or to the surface that seals. Any foreign material or deposits on the cap must be removed. Any foreign material or deposits on the seal must be removed. Any foreign material or deposits on the surface that seals must be removed.

3. Make sure that the coolant level is above the top of the radiator core.

4. Install the filler cap. Tighten the filler cap.
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   Illustration 2	g00286374
   9S-8140 Pressurizing Pump (3) Release valve. (4) Adapter. (5) Hose.

5. Remove hose (5) from adapter (4).

6. Remove the pressure test plug for the radiator top tank.
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   Illustration 3	g00286375

7. Install the end of the hose (5) in the hole for the pressure test plug.

8. Operate the pump until the pointer on the pressure indicator does not increase. The highest pressure indication on the pressure indicator is the point that opens the relief valve. The correct pressure that makes the relief valve open is 105 to 125 kPa (15 to 18 psi).

9. If the relief valve does not open within the pressure specification, the replacement of the relief valve is necessary.

10. If the relief valve is within specifications, check the radiator for outside leakage.

11. Check all connections and hoses of the cooling system for outside leakage.

12. The radiator and the cooling system does not have leakage if the following conditions exist. There is no outside leakage. The pressure reading on the pressure indicator stays same after a five minute period. If the reading on the pressure indicators goes down and you do not see any outside leakage, there is leakage on the inside of the cooling system. Make the necessary repairs.
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    Personal injury can result from escaping fluid under pressure. If a pressure indication is shown on the indicator, push the release valve in order to relieve pressure before removing any hose from the radiator.

13. Remove the hose (5) from the pressure test location on the radiator.

14. Install the plug in the pressure test location.