GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

1

Check for an incorrect or faulty radiator filler cap.

Was an incorrect cap installed, or is the cap faulty?

--

Go to Step 2

Go to Step 3

2

Replace the filler cap.

Is there still a coolant loss?

103 kPa (15 psi)

Go to Step 3

System OK

3

Check for a leaking coolant recovery reservoir or reservoir hose.

Is the coolant recovery reservoir leaking, or is the reservoir hose leaking?

--

Go to Step 4

Go to Step 5

4

Replace the reservoir or the hose. Refer to Coolant Recovery Reservoir Replacement .

Is there still a loss of coolant?

--

Go to Step 5

System OK

5

Check for any loose or damaged radiator hoses and connections.

Are any radiator hoses loose or damaged?

--

Go to Step 6

Go to Step 7

6

Re-seat the hoses and clamps. If necessary, replace the hoses and the clamps. Refer to Radiator Inlet Hose Replacement as required.

Is there still a coolant loss?

--

Go to Step 7

System OK

7

Check for a water pump gasket leak.

Is there a leak at the water pump gasket?

--

Go to Step 8

Go to Step 9

8

Replace the water pump gasket. Refer to Water Pump Replacement .

Is there still a coolant loss?

--

Go to Step 9

System OK

9

Check for a seal leak at the water pump.

Is there a leak at the water pump seal?

--

Go to Step 10

Go to Step 11

10

Replace the water pump. Refer to Water Pump Replacement .

Is there still a coolant loss?

--

Go to Step 11

System OK

11

    •  Fastener Tightening Specifications in Engine Mechanical - 3.1L
    •  Fastener Tightening Specifications in Engine Mechanical - 3.8L

Are the cylinder head bolts tightened to the proper specification?

--

Go to Step 13

Go to Step 12

12

Tighten the cylinder head bolts to the proper specification. If necessary, replace the cylinder head gasket.

Is there still a coolant loss?

--

Go to Step 13

System OK

13

Check for any coolant leaks at the radiator.

Does the radiator have any leaks?

--

Go to Step 14

Go to Step 15

14

  1. Inspect the radiator.
  2. Replace the radiator as necessary. Refer to Radiator Replacement .

Is there still a coolant loss?

--

Go to Step 15

System OK

15

Check the following for leaks:

    • The intake manifold
    • The engine block coolant drain hole plug
    • The knock sensor
    • The heater core

Are any leaks occurring at any of these places?

--

Go to Step 16

System OK

16

Make the necessary repairs or replace the components as necessary in order to repair the leak.

Is there still a coolant loss?

--

--

System OK