For 1990-2009 cars

Step | Action | Value | Yes | No
--- | --- | --- | --- | ---
1 |

1. Visually inspect the cooling system.
2. Inspect the ground under the vehicle.

Is there coolant visible on the ground?

--

Go to Step 3

Go to Step 2

2 | Inspect the cooling system for proper pressure retention. Does the cooling system maintain the correct pressure? | -- | Go to Step 13 | Go to Step 3
3 | Inspect for a leaking radiator. Does the radiator leak? | -- | Go to Step 4 | Go to Step 5
4 | Repair or replace the radiator. Refer to Radiator Replacement . Is there still a loss of coolant? | -- | Go to Step 5 | System OK
5 | Inspect for a leaking coolant recovery reservoir or surge tank. Is there a leak in the reservoir or surge tank? | -- | Go to Step 6 | Go to Step 7
6 | Replace the coolant recovery reservoir or surge tank. Refer to one of the following procedures:

• | Coolant Recovery Reservoir Replacement

• | Radiator Surge Tank Replacement

Is there still a loss of coolant?

--

Go to Step 7

System OK

7 | Inspect for any loose or damaged radiator hoses or connections. Are any radiator hoses or hose connections damaged? | -- | Go to Step 8 | Go to Step 9
8 | Reseat the clamps and hoses. If needed, replace the hoses and the clamps. Refer to the appropriate procedure: Is there still a loss of coolant? | -- | Go to Step 9 | System OK
9 | Inspect for a water pump gasket leak. Is there a leak at the water pump gasket? | -- | Go to Step 10 | Go to Step 11
10 | Replace the water pump gasket. Refer to Water Pump Replacement . Is there still a loss of coolant? | -- | Go to Step 11 | System OK
11 | Inspect for a water pump seal leak. Is there a leak at the water pump seal? | -- | Go to Step 12 | Go to Step 13
12 | Replace the water pump. Refer to Water Pump Replacement . Is there still a loss of coolant? | -- | Go to Step 13 | System OK
13 | Inspect the radiator filler cap. Is the radiator filler cap damaged? | -- | Go to Step 14 | Go to Step 15
14 | Replace the radiator filler cap. Is there still a loss of coolant? | -- | Go to Step 15 | System OK
15 | Inspect cylinder head gasket for leaks. Is the cylinder head gasket leaking? | -- | Go to Step 16 | Go to Step 16
16 | Replace the cylinder head gasket. Refer to the appropriate procedure:

• | Cylinder Head Replacement - Left Side in Engine Mechanical 8.1L

• | Cylinder Head Replacement - Right Side in Engine Mechanical 8.1L

• | Caterpillar® 3126 Unit Repair Manual

Is there still a loss of coolant?

--

Go to Step 17

System OK

17 | Inspect the cylinder head and the cylinder block. Is the cylinder head or cylinder block cracked? | -- | Go to Step 18 | Go to Step 19
18 | Replace or resurface the cylinder head or the cylinder block as needed. Refer to the appropriate procedure:

• | Cylinder Head Replacement - Left Side in Engine Mechanical 8.1L

• | Cylinder Head Replacement - Right Side in Engine Mechanical 8.1L

• | Caterpillar® 3126 Unit Repair Manual

Is there still a loss of coolant?

--

Go to Step 19

System OK

19 | Inspect for a leaking heater core. Is the heater core leaking? | -- | Go to Step 20 | System OK
20 | Repair or replace the components as needed in order to repair the leak. Is there still a loss of coolant? | -- | -- | System OK