HEAD GASKET TEST 2: Compression Shooting Out Of Open Radiator
The second most common test, to see if the head gasket on your 2.2L S10 (or Sonoma, Cavalier, Sunfire, etc.) is blown or not, is to check if engine compression and/or combustion gases are escaping thru' the cooling system. This is another very easy test and does not require any tools whatsoever to do.
Now, before you start, if the engine has been running for an extended amount of time and it's hot, let the engine cool down for at least 1 hour. This is important, or you run the risk of getting scalded with hot coolant.
If your 2.2L Chevy (or GMC or Pontiac) car or pick up doesn't start, well this is not an issue. OK, here are the test steps:
- 1
Remove your pick up or car's radiator's cap.
- 2
Check the coolant level. If empty, add some water or coolant to bring the coolant level to full.
- 3
Have a helper to crank the engine, while you stand at a safe distance from the open radiator.
- 4
You'll see one of two results:
1.) The water or coolant inside the radiator will shoot up and out of the now open radiator.
2.) The coolant will not be disturbed. In other words, cranking the engine will have no effect on the level of the water or coolant in the radiator.
OK, now that the testing part is done, let's take a look at what your results mean:
CASE 1: The coolant bubbled out or shot out from the radiator. This is bad news and this let's you know beyond a shadow of a doubt that the head gasket on your 2.2L Cavalier (or Sonoma, S10, Sunfire, etc.) is blown. No further testing is required.
CASE 2: The coolant DID NOT bubble out NOR shoot out from the radiator. So far so good, but one more test is needed to make absolutely sure the head gasket is OK.
If the engine in your vehicle does not start, go to: HEAD GASKET TEST 3: Testing Engine Compression.
If the engine in your vehicle does start but overheats, go to: HEAD GASKET TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).
HEAD GASKET TEST 3: Testing Engine Compression
One of the most overlooked tests, to see if the head gasket is bad or not, is an engine compression test. Why? Well because most folks will do the two previous tests and they will not see the engine oil mixing with the coolant nor see the combustion gases jumping out of the open radiator and conclude everything is OK. And whatever information they have available never mentions testing the engine compression.
Well, now you know that it is possible for the head gasket to burn and not cause the oil to mix with coolant nor cause the exhaust gases to escape thru' the cooling system. In this test step, you'll be doing a compression test and more importantly, you'll be able to easily interpret those results (with my help) to further confirm or exonerate a blown head gasket.
This test will see if the head gasket on your 2.2L Sonoma (S10 Pick Up, Cavalier, Sunfire, etc.) has burned at a point between cylinders.
If this does happen, the compression/combustion of one cylinder to leak into the other and vice-versa and the compression readings will easily let us know this has happened.
OK, here's what you need to do:
- 1
Disable the ignition system on your 2.2L S10 Pick Up (Sunfire, Cavalier, etc.). It's important that spark is not created and delivered to the spark plug wires.
You can easily accomplish this ‘disabling’ by disconnecting the ignition module's connectors (remember that the ignition module sits underneath both ignition coil packs). - 2
Disconnect all four spark plug wires (from their spark plugs).
- 3
Remove all of the spark plugs.
- 4
Thread in the compression tester by hand, on the first spark plug hole you're gonna' start with.
Do not use any tools to tighten the compression tester. Hand tightening the compression tester is more than enough to get the proper results. - 5
Have a helper crank the engine. Your job is to observe the compression tester.
- 6
Have your assistant stop cranking the engine once the tester's needle stops climbing.
- 7
Now, write down the reading and what cylinder it belongs to on a piece of paper (you can use the illustration above to help you identify the cylinder).
- 8
Remove the compression tester and repeat the above steps in the remaining cylinders.
OK, before I jump into the above compression test result interpretations, let me give you some more detailed information as to what you're trying to accomplish with this test, if the head gasket is burned at a location between 2 cylinders, your compression test readings will give you 2 good compression readings and 2 compression readings that will be 0 PSI. Let me give you a more specific example:
Let's say that I tested my 2.2L GMC Sonoma (or Chevy Cavalier or Potiac Sunfire) and I got the following compression tester readings:
- Cylinder #1 = 165 PSI
- Cylinder #2 = 0 PSI
- Cylinder #3 = 0 PSI
- Cylinder #4 = 170 PSI
The compression readings for cylinders #2 and #3 would be a dead giveaway that the head gasket got fried betweenn those two cylinders. Now, in your car or pick up, you may not see those exact same cylinders with 0 PSI readings. It may be #1 and #2 or it may be #3 and #4, the key here, is that whatever cylinders are affected, two of them will have 0 PSI compression and they will be both be side by side.
OK, let's take a look at what your results mean:
CASE 1: All cylinder compression readings where normal. These compression gauge readings confirm that the head gasket is OK and not burned at a point between two cylinders.
If you still suspect that the head gasket on your 2.2L GM car or pick up is blown, take a look at this section: HEAD GASKET TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).
CASE 2: Two side by side cylinders had 0 PSI compression. This engine compression reading confirms that the head gasket is burned thru' at the point between those two cylinders. You will need to replace the head gasket.
