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| Illustration 1 | g00286266 |
Cooling system pressure at specific altitudes and boiling points of water | |
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Personal injury can result from hot coolant, steam and alkali. At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns. Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand. Cooling System Conditioner contains alkali. Avoid contact with skin and eyes. |
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The coolant level must be to the correct level in order to check the coolant system. The engine must be cold and the engine must not be running.
After the engine is cool, loosen the pressure cap in order to relieve the pressure out of the cooling system. Then remove the pressure cap.
The level of the coolant should not be more than 13 mm (0.5 inch) from the bottom of the filler pipe. If the cooling system is equipped with a sight glass, the coolant should be to the correct level in the sight glass.
Making the Correct Antifreeze Mixtures
Do not add pure antifreeze to the cooling system in order to adjust the concentration of antifreeze. Refer to Operation and Maintenance Manual, "Refill Capacities" for the correct procedure. The pure antifreeze increases the concentration of antifreeze in the cooling system. The increased concentration increases the concentration of dissolved solids and undissolved chemical inhibitors in the cooling system.
The antifreeze mixture must consist of equal quantities of antifreeze and clean soft water. Concentrations of more than 50% of antifreeze may have the adverse effect on the performance of the coolant. Refer to Operation and Maintenance Manual, "Refill Capacities" for the correct antifreeze mixture.
Test Tools For The Cooling System
| Required Tools | |||
|---|---|---|---|
| Tool | Part Number | Part Name | Qty |
| A | 4C-6500 | Digital Thermometer | 1 |
| B | 8T-2700 | Blowby/Air Flow Indicator | 1 |
| C | 9U-7400 | Multitach Tool Group | 1 |
| D | 9S-8140 | Pressurizing Pump | 1 |
| E | 1U-7297 | Coolant/Battery Tester | 1 |
| F | 1U-7298 | Coolant/Battery Tester | 1 |
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Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts. When working on an engine that is running, avoid contact with hot parts and rotating parts. |
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| Illustration 2 | g00876179 |
4C-6500 Digital Thermometer | |
Tooling (A) is used in the diagnosis of faults that cause overheating or overcooling in the engine. This tool can be used to check the temperature in several areas of the cooling system. The testing procedure is in Tool Operating Manual, NEHS0554.
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| Illustration 3 | g00313263 |
8T-2700 Blowby/Air Flow Indicator | |
Tooling (B) is used to check the air flow through the radiator core. Refer to Special Instruction, SEHS8712, "Using the 8T-2700 Blowby/Air Flow Indicator " for the test procedure for checking blowby and air flow.
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| Illustration 4 | g00286276 |
9U-7400 Multitach Tool Group | |
Tooling (C) is used to measure the fan speed. Refer to Operating Manual, NEHS0605, " 9U-7400 Multitach Tool Group " for the testing procedure.
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| Illustration 5 | g00286369 |
9S-8140 Pressurizing Pump | |
Tooling (D) is used to test the filler caps. This tool is also used to pressure test the cooling system for leaks.
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| Illustration 6 | g00439083 |
1U-7297 Coolant/Battery Tester or 1U-7298 Coolant/Battery Tester | |
Check the coolant frequently in cold weather for the correct glycol concentration. Use either Tooling (E) or Tooling (F) in order to ensure adequate freeze protection. The testers are identical except for the temperature scale. The testers give immediate, accurate readings. The testers can be used for antifreeze/coolants that contain ethylene or propylene glycol.
Checking the Filler Cap
| Required Tools | |||
|---|---|---|---|
| Tool | Part Number | Part Name | Qty |
| D | 9S-8140 | Pressurizing Pump | 1 |
One cause for a pressure loss in the cooling system can be a faulty seal on the radiator pressure cap.
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| Illustration 7 | g00296067 |
Typical schematic of filler cap (1) Sealing surface between the pressure cap and the radiator | |
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Personal injury can result from hot coolant, steam and alkali. At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns. Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand. Cooling System Conditioner contains alkali. Avoid contact with skin and eyes. |
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To check for the amount of pressure that opens the filler cap, use the following procedure:
- After the engine cools, carefully loosen the filler cap. Slowly release the pressure from the cooling system. Then, remove the filler cap.
- Inspect the pressure cap carefully. Look for damage to the seal. Look for damage to the surface that seals. Remove any debris on the cap, the seal, or the sealing surface.
Carefully inspect the filler cap. Look for any damage to the seals and to the sealing surface. Inspect the following components for any foreign substances:
- Filler cap
- Seal
- Surface for seal
Remove any deposits that are found on these items, and remove any material that is found on these items.
- Filler cap
- Install the pressure cap onto Tooling (D) .
- Observe the exact pressure that opens the filler cap.
- Compare the pressure to the pressure rating that is found on the top of the filler cap.
- If the filler cap is damaged, replace the filler cap.
Testing The Radiator And Cooling System For Leaks
| Required Tools | |||
|---|---|---|---|
| Tool | Part Number | Part Name | Qty |
| D | 9S-8140 | Pressurizing Pump | 1 |
Use the following procedure to test the radiator and the cooling system for leaks.
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Personal injury can result from hot coolant, steam and alkali. At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns. Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand. Cooling System Conditioner contains alkali. Avoid contact with skin and eyes. |
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- When the engine has cooled, loosen the filler cap to the first stop. Allow the pressure to release from the cooling system. Then remove the filler cap.
- Make sure that the coolant covers the top of the radiator core.
- Install Tooling (D) onto the radiator.
- Use Tooling (D) to increase the pressure to an amount of 20 kPa (3 psi) more than the operating pressure of the filler cap.
- Check the radiator for leakage on the outside.
- Check all connections and hoses of the cooling system for leaks.
The radiator and the cooling system do not have leakage if all of the following conditions exist:
- You do NOT observe any leakage after five minutes.
- The dial indicator on Tooling (D) remains constant beyond five minutes.
The inside of the cooling system has leakage only if the following conditions exist:
- The reading on Tooling (D) decreases.
- You do NOT observe any outside leakage.
Make any repairs, as required.
- You do NOT observe any leakage after five minutes.