Diagnosing a blown head gasket on your Honda Accord or Odyssey or Prelude (or Isuzu Oasis) can be easily done with or without tools. I have used three different methods, that I'm going to explain in detail in this article, that have been very effective in troubleshooting a bad head gasket.
Two of them you can accomplish with absolutely no tools. The third is done with a compression tester and the fourth is done with a combustion leak detector. All of them are explained in a step-by-step manner to help you get down to the bottom of the issue on your Honda Accord (Odyssey, Prelude).
Before we jump into the article, the following tutorials may be of help too:
- How To Test The Radiator Fan Motor (Honda 2.2L, 2.3L).
- How To Test The Radiator Fan Relay (Honda 2.2L, 2.3L).
- How To Avoid A Blown Head Gasket (Honda 2.2L, 2.3L).
Contents of this tutorial:
- Symptoms Of A Blown Head Gasket.
- HEAD GASKET TEST 1: Engine Oil The Color Of ‘Coffee With Too Much Creamer’
- HEAD GASKET TEST 2: Combustion Gases Expelled From an Open Radiator.
- HEAD GASKET TEST 3: Doing A Compression Test To Check For A Blown Head Gasket.
- TEST 4: Using A Chemical Block Tester (Combustion Leak Tester).
- Related Test Articles.
You can find this tutorial in Spanish here: Cómo Probar El Empaque De La Cabeza (Honda 2.2L, 2.3L) (at: autotecnico-online.com).
Symptoms Of A Blown Head Gasket
The most common cause of a blown head gasket is that the engine overheated due to one of the following: 1) The radiator fan not working, 2) Engine has no coolant, due to a leak somewhere in the engine's cooling system 3) Thermostat went bad and is stuck closed. The most common symptoms a blown head gasket are:
- Your car or mini-van 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.
- The car or mini-van won't start.
1.) You have already verified it's not an ignition system problem because you have spark coming out at all of the spark plug wires.
2.) You know it's not a lack of fuel, because you have verified that the fuel pump is delivering fuel to the fuel injectors.
- The engine oil is thick and tan to off-white color.
TEST 1: Engine Oil The Color Of ‘Coffee With Too Much Creamer’
Although I'm presenting 3 different tests to check for a blown head gasket, there's a good chance that you may need only one. So, if this first head gasket test let's you know that the gasket is blown, then you don't need to continue to the rest.
Now, if one test doesn't prove conclusively that the head gasket is blown, go to the next one. The reason for this is that a vehicle experiencing a blown head gasket condition may present only one of the many symptoms that these 3 tests are testing for. If this happens to your Honda, I'm confident that one of the three tests will nail down the problem.
OK, I'll stop talking and we'll get this show on the road, this is what you need to do:
Open your Honda's hood.
Pull the engine oil dipstick out of the engine.
Now, visually check the color of the oil and its viscosity (that's on the dipstick).
You'll see one of two things:
1.) The oil on the dipstick is a creamy tan color.
2.) The oil on the dipstick is a normal color and viscosity.
Take a look at the following interpretations to find out which one best fits what you have observed of the color of the oil:
CASE 1: The color of the oil is a light tan, like coffee with too much creamer. This confirms that the head gasket is blown and that it's letting coolant mix with the engine oil.
If you're wondering why the oil looks like this? The principal reason is that your Honda over-heated and:
1.) The cylinder head warped which caused the head gasket to burn.
2.) and a burned head gasket 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, it does not confirm the condition of the head gasket yet, go to TEST 2.
Here's why: In the majority of the cases, a blown head gasket will cause the engine's coolant to mix with the oil, but not always. Therefore one or maybe two more tests are needed 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.