Blowing a head gasket can be a very expensive repair. It could even cost you as much as the car is worth in some cases. A few things can cause the head gasket on your motor to fail.
1. The Car Overheats
When a car overheats, it has extreme temperatures above what the engine was designed to handle, especially the gaskets. A couple of things can happen at this point. Either the gasket gets ruined and opens an easy path for fluids or combustion events to mix or the head can crack giving you the same result.
2. Old Age of Coolant
As the coolant gets old, it starts to turn acidic which will eat away at the gasket and eventually make a pathway into the other chambers of the head.
3. Failure of Fasteners or Head Bolts
The more miles put on the vehicle the more likely some of the major components can fail. failure of fasteners or bolts is not as common but it can happen. Partially because of the acidic coolant eating away at it for an extended period of time or due to vibrations and stress for many years. Once it loosens that hold on the head it can create just enough space for fluids to travel where they are not desired.
4. Improper Engineering
Unfortunately there is nothing you can do to prevent this one. Some cars are notorious for blowing head gaskets at certain intervals. For instance some of the earlier Chevy Cavaliers are known to do this and when repairing them you can see it usually always happens in the same place on the head.
How Can i Tell if my Head Gasket is Blown?
1. White Smoke Out of The Tailpipe
When the coolant leaks into the cylinder it becomes part of the air/fuel mixture. When it is burnt it creates a white smoke and has a distinct smell.
2. Chocolate Milkshake Oil
It looks tasty but it's not as good as it looks. When coolant gets into the oil cavities in the head or block it makes the oil turn into a milkshake color. The freshness of the oil determines the color but generally it looks like that chocolate milkshake.
3. Steam in Coolant System
Instead of coolant getting into the combustion event the opposite can happen as well. When combustion gets into the coolant system the pressure will push all the coolant into the overflow container and most likely out of the system, onto the ground and the car will overheat. Pulling the radiator cap will show you the steam. If it's like a customers car we had recently it will blow smoke out of the radiator.
4. Coolant Leaking Out of the Head
This one doesn't create all the other exciting events but it's just as important. Simply looking at the motor where the head meets the block you can see moisture or if it's serious enough the color of the coolant. Sometimes it's not too obvious so if the car keeps needing coolant every so often, this could be a sign that this is the problem.
Getting a head gasket replaced is no cheap replacement so here are a few ways to prevent this from happening.
1. Change Coolant Regularly
The rule of thumb is to change the coolant every 2 years or 30,000. A good way to check yourself is to grab out the good old litmus paper. Coolant is on the alkaline side of the PH spectrum. A good reading is around 8.5-10.5. Although the newer cars are looking for readings of 9.5 or above to stay healthy. Like I said before with age, it gets more acidic so the lower that number becomes the more corrosive it will be to your motor. If it's a neutral 7 it's time to change it.
2. Prevent the Car From Overheating
Another way is to keep your overheating to a minimum. For instance, a hot day stuck in traffic is a typical time the car will overheat. If it does, pull over and shut the car off for a while to let it get back to a good operating temperature. Once cool, check your fluid levels. If low add some water for the time being until you can get some antifreeze to put in. Keep a sharp eye on the temp gauge to ensure it doesn't go too high as you continue to travel.