How To Test A Blown Head Gasket On GM 2.0L, 2.2L, 2.5L

Testing for a blown head gasket on your 2.2L S10 (or Cavalier, Sunfire, etc) can be done is several different ways. In this article, I'm gonna' show you how to do three of the most effective head gaskets tests that have always nailed a blown head gasket for me or eliminated it as the cause of the problem.

All three of the tests are explained in a step-by-step manner. Two (of the three) are done without any tool whatsoever. The last one requires an engine compression tester. OK, let's get started.

Here are the contents of this article at a quick glance:

  1. Symptoms Of A Blown Head Gasket.
  2. HEAD GASKET TEST 1: Oil The Color Of Coffee With Too Much Cream.
  3. HEAD GASKET TEST 2: Compression Shooting Out of Open Radiator.
  4. HEAD GASKET TEST 3: Engine Compression Test.
  5. HEAD GASKET TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).
  6. Related Test Articles.

Symptoms Of A Blown Head Gasket

The most common cause of a blown head gasket is that the engine overheated because: 1) The radiator fan (Cavalier, Sunfire) or fan clutch (Sonoma, S10 Pick Up) is not working, 2) All of the coolant leaked out of the engine and you kept driving it this way. 3) Thermostat went BAD and is stuck closed and the coolant could not circulate. The most common symptoms a blown head gasket are:

  1. Your 2.2L S10 Pick Up (or Cavalier, Sunfire, Sonoma) is overheating. You know it's not the fan (or fan clutch) or thermostat because they're working.
  2. White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
  3. Your 2.2L GM pick up or car won't start. You have already verified it's not an ignition system problem because you have spark coming out at all of the spark plug wires. You know it's not a lack of fuel, because you have verified that the fuel pump is delivering fuel to the fuel injectors.
  4. The engine oil is thick and tan to off-white color (mixed with coolant).

HEAD GASKET TEST 1: Oil The Color Of ‘Coffee With Too Much Cream’

Checking The Engine Oil to See if it's Mixed With Coolant

There's a good chance that you may not have to do all three tests that I'm presenting to you here in this article. The reason for this is that in the majority of the cases, a blown head gasket will present several observable symptoms (although this is not an absolute truth). So, this first test may conclusively confirm that the head gasket is BAD or it may not. Whatever the case... the other two test will confirm or exonerate the head gasket as blown.

OK, I'll stop talking and we'll get this show on the road... this is what you need to do:

  1. 1

    Open the Hood on your S10 (or Jimmy, Sunfire, Cavalier, etc.) and check the engine's oil by pulling out the engine's oil dipstick.

  2. 2

    Now, visually check the color of the oil and its viscosity (that's on the dipstick). You are going to confirm one of two things with this test:

    1.) Is the oil on the dipstick a creamy tan and is the oil thick? Or...

    2.) Is the oil on the dipstick its normal color and viscosity?

OK, let's interpret what the color of the engine oil means, choose one of the following CASES:

CASE 1: The color of the oil is a light tan, like coffee with too much cream, this is BAD news and confirms that the head gasket on your 2.2L car or pick up is blown. You'll need to replace the head gasket to solve this problem.

If you're wondering why the oil looks like this? The principal reason is that your car or pick up over-heated and :

1.) The overheating caused the cylinder head to warp. This in turn caused the head gasket to burn.

2.) And a burned head gasket loses its sealing power/ability and can not seal the oil and coolant ports in both the engine block and the cylinder head (especially with a warped cylinder head).

3.) This leads to the coolant entering the engine oil pan.. As both oil and coolant mix... the resulting combination gets thick and becomes an off-white color.

CASE 2: The color of the engine oil is normal, Although this is a good result, you're not out of the woods yet, since you'll need to do two more tests to confirm the condition of the head gasket, go to HEAD GASKET TEST 2.

Here's why: In about 90% of times that a head gasket blows on a GM 2.2L equipped car or pick up... coolant will enter into the crankcase and mix with the engine oil, but not always. Thankfully, there are several more tests that you can do to make sure that the head gasket is really blown or not. The next test is to see if the engine's compression/ combustion gases are escaping thru' the radiator.