GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

1

Check for an incorrect or damaged radiator filler cap.

Was the incorrect radiator cap installed or is the radiator cap damaged?

103 kPa (15 psi)

Go to Step 2

Go to Step 3

2

Do a cap pressure test. Refer to Pressure Cap Testing . If necessary, replace the cap.

Is there still a loss of coolant?

--

Go to Step 3

System OK

3

Check for a leaking coolant recovery reservoir or for a loose or damaged reservoir hose.

Is there a leak in the reservoir or is the reservoir hose damaged?

--

Go to Step 4

Go to Step 5

4

Replace the coolant recovery reservoir. 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 or hose connections damaged?

--

Go to Step 6

Go to Step 7

6

Reseat the hoses and clamps. If necessary, replace the hoses and the clamps.

Is there still a loss of coolant?

--

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 loss of coolant?

--

Go to Step 9

System OK

9

Check for a water pump seal leak.

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 or Water Pump Replacement .

Is there still a loss of coolant?

--

Go to Step 11

System OK

11

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

Are the cylinder head bolts tightened to specifications?

--

Go to Step 13

Go to Step 12

12

Tighten the cylinder head bolts to specifications. Refer to Fastener Tightening Specifications in Engine Mechanical. If necessary, replace the cylinder head gasket.

Is there still a loss of coolant?

--

Go to Step 13

System OK

13

Inspect the radiator and check for any coolant leaks.

Is the radiator leaking coolant?

--

Go to Step 14

Go to Step 15

14

Replace the radiator. Refer to Radiator Replacement .

Is there still a loss of coolant?

--

Go to Step 15

System OK

15

Check the following for leaks:

    • The intake manifold
    • The engine block coolant drain hole plug or the knock sensors
    • The heater core

Are any coolant leaks occurring at these locations?

--

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 loss of coolant?

--

--

System OK