This tutorial will help you to test for a blown head gasket on the 3.5L V6 equipped GM vehicles. These are the: 2006-2010 Chevrolet Impala, 2005-2009 Chevrolet Malibu, 2005-2006 Chevrolet Uplander, 2005-2010 Pontiac G6, 2005-2006 Pontiac Montana.
This tutorial will explain the four tests that are usually done at an automotive repair shop to either confirm or exonerate the head gaskets as the cause behind a no-start problem or an engine overheating problem.
Contents of this tutorial at a glance:
You can find this tutorial in Spanish here: Cómo Probar Los Empaques De La Cabeza (2004-2008 3.5L Malibu) (at: autotecnico-online.com).
Symptoms Of A Blown Head Gasket
Since the 3.5L V6 engine has two cylinder heads, it comes equipped with two head gaskets.
When one of these two or both head gaskets fail, you're going to see some very specific symptoms.
But before I jump into a list of symptoms, I can tell you that usually head gasket problems fall into one of two categories: either the engine doesn't start or the engine starts but it overheats.
Here's a list of symptoms you'll see when the engine starts and runs but overheats due to a blown head gasket:
- The exhaust smells like antifreeze being burned.
- White smoke comes out of the tailpipe as soon as the engine starts and runs.
- A rough idle condition usually accompanied by a P0300 misfire trouble code.
- Specific misfire cylinder codes like: P0301, P0302, P0303, P0304, P0305, or P0306.
- A lack of power when you accelerate the vehicle.
TEST 1: Engine Oil The Color Of Coffee With Too Much Creamer
Usually, but not always, the most common end result of a blown head gasket is coolant mixing with the engine oil in the crankcase.
So if we were to pull out the engine oil dipstick, the oil would look like coffee with way too much creamer.
So for our very first test, we're going to check the color of the engine oil sticking to the engine oil dipstick.
If the oil does look like a milky white substance, then you can conclude that the head gaskets are blown on your vehicle's 3.5L V6 engine.
If the engine oil color looks okay, then we can move on to the next test.
These are the test steps:
- 1
Open your 3.5L V6 equipped vehicle's hood and pull out the engine oil dipstick.
What you're looking for is to make sure that the engine oil IS NOT mixed with coolant. If the engine oil is mixed with coolant, it'll be the color of 'coffee with too much cream'. - 2
What color is the engine oil?
1.) The engine oil is a creamy tan/off-white color.
2.) The engine oil is its usual normal color.
Let's examine your test results:
CASE 1: The engine oil sticking to the dipstick has a normal color. So far so good but we're not out of the woods yet. The next step is to see if the coolant is being pushed out of the coolant reservoir while we crank the engine. For this test go to: TEST 2: Coolant Shooting Out From Opened Radiator.
CASE 2: The oil sticking to the dipstick looks like coffee with way too much creamer. This test result confirms that one or both head gaskets are blown on your vehicle's 3.5L V6 engine.
