GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

1

Check for an incorrect or faulty radiator filler cap. Refer to Pressure Cap Testing .

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 or Radiator Outlet Hose Replacement .

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

Make sure the cylinder head bolts are tightened to specification. Refer to Fastener Tightening Specifications in Engine Mechanical.

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. Refer to Cooling System Leak Testing .

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