GM Service Manual Online
For 1990-2009 cars only

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:

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.

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