How To Test For A Blown Head Gasket (GM 2.4L Quad 4)

How To Test For A Blown Head Gasket On GM 2.3L, 2.4L Quad 4

Overheating is the number one cause of a blown head gasket on a 2.4L Quad 4 equipped Buick (or Chevy, Olds, Pontiac) car. If you think that your car has a blown head gasket, this article will help you to find out with three fast and easy tests.

All three tests are explained in detail and more importantly, I'll show you how to interpret your test results. Also, for the first two tests, you don't need any tools what-so-ever to do the tests with. The third test is a cylinder compression test for which you'll need a compression tester.

Symptoms Of A Blown Head Gasket

A blown head gasket is always the result of severe engine overheating. This engine overheating can be caused by one of several factors. For example: 1) The radiator fan 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:

  • Your 2.4L Grand Am (Cavalier, Malibu, Achieva, Alero, etc.) is overheating. You know it's not the fan or thermostat.
  • White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
  • Your 2.4L GM 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 boots. You have also verified that this ‘no-start condition’ is not due to a lack of fuel (by doing a fuel pressure test).
  • The engine oil is thick and tan to off-white color (mixed with coolant).

HEAD GASKET TEST 1: Engine Oil Mixed With Coolant

Checking The Engine Oil To See If It's Mixed With Coolant

When a head gasket gets blown, due to overheating, it will usually present three very distinct results which are: 1.) engine oil mixed with coolant, 2.) exhaust gases, engine compression escaping thru' the cooling system (radiator), and/or 3.) Loss of compression on two adjacent cylinders. Well, in this first test, you're gonna' verify symptom number one.

There's a very good chance that if the head gasket is really blown on your 2.4L Quad 4 engine, you may only have to perform the first two tests. If this is the case, you can skip head gasket TEST 3. So, before you start, take a look at the whole article and familiarize yourself with the test steps of all three.

OK, to this show on the road, this is what you need to do:

  1. 1

    Open the hood on your car and check the engine's oil by pulling out the engine's oil dipstick.

  2. 2

    What you need to do is check to see what the color of the engine oil is. Depending on if the head gasket is blown or not, you'll see one of two things:

    1.) The engine oil on the dipstick a creamy tan, off-white color.

    2.) The oil on the dipstick will be 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 creamer. This is not good and this test result confirms that your 2.4L Quad 4 car does have a blown head gasket. Replacing the head gasket will be the solution to the problem.

This happens because:

1.) Your car overheated either due to a bad thermostat, or bad water pump, or a bad fan motor, or lack of coolant and the cylinder head warped.

2.) Once the cylinder head warps, the head gasket starts to burn and a burned head gasket can not keep the engine oil and coolant from mixing anymore (and exhaust/compression gases from exiting thru' the cooling system).

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: Coolant Shooting Out Of The Radiator.

Most of the time, when you're troubleshooting a blown head gasket on a 2.4L Quad 4 equipped Buick, Chevrolet, Oldsmobile or Pontiac, you will see the engine oil completely mixed with coolant and the oil will have that milky off-white color to it, but not always. Thankfully, there are two more tests you can do to further confirm a blown head gasket or exonerate the head gasket.

Buick Vehicles:

  • Skylark 2.3L, 2.4L
    • 1994, 1995, 1996, 1997, 1998

Chevrolet Vehicles:

  • Cavalier 2.3L, 2.4L
    • 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002
  • Malibu 2.4L
    • 1997, 1998, 1999

Oldsmobile Vehicles:

  • Achieva 2.3L, 2.4L
    • 1994, 1995, 1996, 1997, 1998
  • Alero 2.4L
    • 1999, 2000, 2001

Pontiac Vehicles:

  • Grand Am 2.3L, 2.4L
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
  • Sunfire 2.4L
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002