In this tutorial, I'm gonna' show you the 4 basic tests that check for a blown head gasket.
The first two tests check for two of the most common head gasket failures: engine oil mixed with coolant and combustion/compression pressure shooting out of the radiator (with cap removed). Both of these can be accomplished in under 5 minutes or less.
The third test is a compression test and I'll show you how it's done and I'll also help you interpret its results.
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: Coolant Shooting Out From Open Radiator.
- HEAD GASKET TEST 3: Engine Compression Test.
- 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 Cabeza (1.8L Toyota Corolla) (at: autotecnico-online.com).
Symptoms Of A Blown Head Gasket
If your Toyota still starts and runs, the most common symptoms of a blown head gasket is that the engine overheats rapidly.
Here are a few other common symptoms a blown head gasket:
- Your Toyota is overheating. You've checked that:
- Thermostat is good.
- Fans are working.
- Radiator is not busted (leaking coolant).
- Water pump is OK (not leaking coolant).
- Cooling system is full of coolant.
- White smoke is coming out of the tail-pipe and it smells like anti-freeze being cooked.
- Your Toyota won't start. You've checked:
- All COP ignition coils are sparking.
- All fuel injectors are injecting.
- Fuel pump is good.
- The engine oil is thick and tan to off-white color.
HEAD GASKET TEST 1: Engine Oil The Color Of ‘Coffee With Too Much Creamer’
This first test is a simple test and checks for one of the most common results of a blown head gasket on a Toyota which is coolant mixing with the engine oil.
In most cases, this is probably the only test you may have to do, to verify a blown head gasket, and not have to do the other two tests. But if this test doesn't conclusively verify a blown head gasket, then by all means proceed to the other two head gasket tests.
OK, I'll stop talking and we'll get this show on the road, this is what you need to do:
Open your Toyota'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 creamer’.
What color is the engine oil?
1.) Is it a creamy tan/off-white color.
2.) The engine oil will be its usual normal color.
Alright, let's interpret the color of the engine oil:
CASE 1: The color of the oil is a light tan, like coffee with too much creamer. This result confirms that your Toyota's head gasket is blown.
If you're wondering why the oil looks like this? Well this is what happened:
1.) Your Toyota overheated to the point that the cylinder head warped (since it's made out of aluminum). This led to the head gasket to burn.
2.) Once the head gasket burns and the head warps, the head gasket is unable to keep engine oil, coolant, and compression/ exhaust gases from mixing.
3.) This leads to the coolant entering the engine oil pan. As both of these mix, the result is an engine oil that is an off-white/tan color.
CASE 2: The color of the engine oil is normal. So far so good, but more testing is necessary to make sure the head gasket is not blown (especially if your Toyota is overheating or not starting), go to: HEAD GASKET TEST 2: Coolant Shooting Out From Open Radiator.
Here's the reason why: In about 90% of the times, a blown head gasket will cause the engine's coolant to mix with the oil, but not always. And so another test or tests are needed to either confirm a blown head gasket or exonerate the head gasket as blown. The next test is to see if the engine's compression/combustion gases are escaping thru' the radiator.