GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Check for a leaking radiator.

Is the radiator leaking?

Go to Step 2

Go to Step 3

2

Repair or install new parts as necessary.

Is the repair complete?

System OK

--

3

Check for a leaking heater core.

Is the heater core leaking?

Go to Step 2

Go to Step 4

4

Check for a faulty surge tank pressure cap.

Is the cap operating properly?

Go to Step 5

Go to Step 2

5

Check for a leaking coolant recovery hose, a cracked recovery reservoir or a nicked reservoir neck.

Is the reservoir or the hose leaking?

Go to Step 2

Go to Step 6

6

Check for any loose or damaged hoses and connections.

Are any hoses damaged or are any hose connections leaking?

Go to Step 2

Go to Step 7

7

Check for a cracked thermostat housing or a leaking thermostat seal.

Is the thermostat housing cracked or is there a seal leak?

Go to Step 2

Go to Step 8

8

Check for a cracked water pump or a leaking water pump seal.

Is the water pump cracked or is there a leaking seal?

Go to Step 2

Go to Step 9

9

Check for a leaking auxiliary water pump.

Is an auxiliary water pump leaking?

Go to Step 10

Go to Step 11

10

Replace the water pump.

Is the repair complete?

System OK

Go to Step 11

11

Check for a leaking cylinder head drain hole plugs.

Are any drain hole plugs leaking?

Go to Step 2

Go to Step 12

12

Check for a cracked cylinder head.

Are either of the cylinder heads cracked?

Go to Step 2

Go to Step 13

13

Check for a leaking cylinder head gasket(s).

Is the cylinder head gasket leaking?

Go to Step 2

Go to Step 14

14

Check for a cracked throttle body or a gasket leak.

Is the throttle body cracked or is there a gasket leak?

Go to Step 2

Go to Step 15

15

Check for a cracked cylinder block.

Is the cylinder block cracked?

Go to Step 2

Go to Step 16

16

Check for any porous castings.

Are the castings OK?

System OK