A leak from the engine head gasket is a rather serious inconvenience. If you don't want to take the car to the workshop for a professional replacement you can try to repair the damage yourself using an engine sealant. This product provides a temporary or permanent solution to the problem. If the break is too serious, however, you must have the piece replaced by a mechanic.
Steps
Part 1 of 3: Diagnosing a Leaking Engine Head Gasket
Step 1. Check under the oil tank cap
When the engine head gasket has a leak, the common symptom is the formation of a viscous, mayonnaise-like substance under the oil cap.
- The substance is white, creamy and accumulates on the lower part of the cap; this is a clear indication of a gasket leak.
- However, the absence of this "mayonnaise" does not automatically rule out that the garnish does not leak.
Step 2. Look for white smoke from the tailpipe
When the gasket is damaged, the coolant enters the cylinders and is burned along with the air and fuel, producing a different colored exhaust smoke than usual; it typically turns gray or white instead of the usual dark shade.
As the loss worsens, the smoke becomes whiter and whiter
Step 3. Drain the oil from the engine and look for traces of coolant
When you change the oil, inspect the old one to see if there is also radiator fluid. A leak at the engine head gasket allows the coolant to seep into the oil; since these are two substances with different consistencies, the liquids tend to separate.
- If you see clear circular streaks inside the oil, they are probably coolant.
- If there is enough radiator fluid to be able to see its color, remember that it is usually green, orange or pink.
Step 4. Pay attention if the engine stalls
When it has difficulty starting you can feel and hear a strong vibration that resonates throughout the vehicle. You may also notice a jolt in the speedometer and tachometer needle at the vibration. This reaction is triggered by the radiator fluid entering the cylinders and preventing the fuel from burning.
- A combustion problem often causes the engine failure light on the dashboard to come on.
- An engine head gasket leak is one of the problems that trigger this warning light to come on.
Step 5. Use an OBDII scanner
If the engine light comes on, use an on-board diagnostic PDA to check the vehicle's computer error message. The error code can make you better understand what the problem is with the machine.
- If the error indicates a combustion problem, the gasket may be responsible.
- Many auto parts stores use the OBDII scanner to check for error codes for free.
Step 6. Monitor the temperature gauge
When the engine head gasket is malfunctioning, it prevents proper temperature regulation. If the engine gets hotter than normal or starts to overheat, it could be a symptom of a gasket leak.
- If the car overheats, pull over immediately and turn off the engine.
- Driving an overheated vehicle causes severe damage to the engine and cylinder head.
Part 2 of 3: Draining the Old Coolant
Step 1. Lift the vehicle
In order to access the lower point of the cooling system, you must lift the machine to an adequate height to be able to work under the body. Raise it with a jack by inserting the latter into the appropriate notches and pressing or turning the lever.
- When the machine is raised enough, insert jacks under it to support its weight.
- If you do not know where to find the points to pry the jack, consult the owner's manual of the vehicle.
- Never work under a car supported only by the jack.
Step 2. Place a container under the radiator
You need a container large enough to hold twice as much refrigerant fluid leaking from the system. If you don't have a large enough container, get a bucket with the same capacity as the plant. After carrying out the first antifreeze drain, you will need to pour the contents of the bucket into another sealable container.
- Place the container under the radiator near the drain valve.
- Consult the user manual of the machine to know the capacity of the refrigerant system and, consequently, that of the container you need to use.
Step 3. Open the drain valve
Use a wrench to unscrew the nut located on the bottom of the radiator; in this way you allow the liquid to flow into the container. Wait for the system to drain completely before closing the valve.
- Be careful not to spill the liquid on the ground: it is highly polluting.
- Open the radiator cap to speed up the process.
Step 4. Close the valve and fill the radiator with water
When the system is empty, use the same wrench to tighten the drain nut; at this point you can open the radiator cap and pour plain water into it to fill the system.
- If the cap is badly worn or damaged you should replace it with a new one that you can buy at an auto parts store.
- If you can't locate the radiator cap, consult your car's maintenance manual.
Step 5. Unplug the thermostat
This is the element that keeps the operating temperature constant by opening the cooling system, so as to allow the liquid to pass through the radiator and dissipate heat thanks to the air flow, when it gets too hot. Disconnecting the thermostat prevents it from activating as you add the sealant.
- Detach the tube that joins the top of the thermostat.
- If in doubt, refer to the instructions in the maintenance manual to find the thermostat accurately.
Step 6. Start the engine and set the heating system to maximum temperature
When you have filled the system with water, turn on the vehicle to circulate the liquid in the system and be able to wash away the residual refrigerant when you open the valve again.
- Leave the engine running for about 10 minutes.
- Check the temperature and turn off the vehicle just before it starts to overheat.
Part 3 of 3: Fill the Cooling System with the Sealing Mix
Step 1. Open the valve to let the water out
When you've run it all over the cooling system, unscrew the drain nut again to get rid of the water as well; wait for it to drain completely before closing the valve.
- This is the same process you should follow to drain and flush the cooling system.
- The water carries away the antifreeze residues that remained in the system even after the first drain.
- During this step, plug in the thermostat again.
Step 2. Fill the radiator system with water and coolant
Use a mixture of equal parts water and antifreeze. Ask the auto parts store clerk what type of coolant is right for the vehicle you own.
- You can buy a ready-made blend or make it yourself.
- Pour the coolant through the radiator opening and wait a minute to allow it to reach the entire system; then continue to top up until you have transferred a quantity of fluid equal to the capacity of the system.
Step 3. Pour in the sealant for the motor head gasket
Put it in the system through the radiator opening; Read the instructions for the specific product you bought, as they may vary by brand.
Typically, it is sufficient to pour the sealant into the radiator along with the water and coolant
Step 4. Drive the vehicle for 15-20 minutes
The sealant must travel the entire cooling system and reach the gasket. Start the engine and let it idle or take a test drive for 15-20 minutes to spread the sealant.
- Also in this case, make sure that the engine does not overheat and if necessary switch it off immediately.
- After 15-20 minutes, turn off the engine and let it sit for a few hours.
Step 5. Re-evaluate the condition of the motor head gasket
Use the same criteria described in the first part of the article to first understand if there is a problem; in some cases the sealant can provide a definitive solution, but in other situations it can be completely useless.
- Monitor the car closely for signs of a gasket leak.
- Having it replaced is the only truly permanent solution.
