How To Test A Blown Head Gasket (1995-1999 GM 3.8L)

If you're wondering how to test a blown head gasket, on your 3.8L V6 equipped GM vehicle, this is the tutorial you need.

In this tutorial, I'll explain the 4 test you can perform to find out if one or both of the head gaskets are blown on your vehicle.

Two of those tests require no tools whatsoever and can be done in a matter of minutes.

APPLIES TO: This tutorial applies to the following vehicles:

• 3.8L Buick LeSabre: 1996, 1997, 1998, 1999.
• 3.8L Buick Park Avenue: 1996, 1997, 1998, 1999.
• 3.8L Buick Regal: 1996, 1997, 1998, 1999.
• 3.8L Buick Riviera: 1996, 1997, 1998, 1999.

• 3.8L Chevrolet Lumina: 1998, 1999.
• 3.8L Chevrolet Monte Carlo: 1998, 1999.

• 3.8L Oldsmobile 88 (Eighty-Eight): 1996, 1997, 1998, 1999
• 3.8L Oldsmobile 98 (Ninety-Eight): 1996
• 3.8L Oldsmobile Intrigue: 1998, 1999
• 3.8L Oldsmobile LSS: 1996, 1997, 1998, 1999
• 3.8L Oldsmobile Regency: 1997, 1998

• 3.8L Pontiac Bonneville: 1996, 1997, 1998, 1999
• 3.8L Pontiac Grand Prix: 1997, 1998, 1999

Symptoms Of A Blown Head Gasket

For the most part, a blown head gasket will cause one of two problems. The most common is that the engine runs but overheats within minutes.

The second most common problem, is that the engine cranks but does not start.

If the engine starts and runs, you'll see one or more of the following symptoms:

• White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
• The engine oil is thick and a tan to off-white color (mixed with coolant).
• Rough idle.

Whether the engine starts and overheats or doesn't start, this tutorial will help you find out if the problem is due to a blown head gasket problem.

TEST 1: Oil The Color Of Coffee With Too Much Creamer

The very first test that I perform, when diagnosing a blown head gasket, is checking the condition and color of the engine oil sticking to the engine oil dipstick.

Why check the color of the engine oil? Because in the majority of the cases, when a head gasket fails, you're going to have engine coolant going into the crankcase.

This causes the oil in the crankcase to mix with coolant and will turn into a mixture that looks like coffee with way too much creamer.

We'll start off our round of tests with this easy and fast test.

This is what you need to do:

1. 1

   Open your vehicle's hood.

2. 2

   Pull out the engine's oil dipstick.

3. 3

   Check what the color of the oil is and how thick it is.

4. 4

   You'll see one of two things:
   
   1.) The oil on the dipstick is a creamy, off-white color and is thick as syrup.
   
   2.) The oil is its normal color and viscosity.

Let's examine your test result:

CASE 1: The engine oil looks like 'coffee with too much creamer'. This is not good since it confirms that one or both head gaskets are blown.

CASE 2: The color of the engine oil is normal. This is the correct and expected test result.

The next step is to check to see if compression/exhaust gases are leaking into the cooling system. Go to: TEST 2: Exhaust Gases Shooting Out Of The Radiator.