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How to Repair & Replace a Blown Head Gasket

Car trouble is one thing we wished never existed. A blown head gasket, to be exact, is what we dread the most. It can amount to thousands of dollars in repair, not to mention all the stress and frustration we’re bound to feel.
That’s why it’s no surprise that many want to pull off a DIY instead. However, it’s always best to be knowledgeable and possess a certain level of experience and confidence to do all the repairs yourself.

The good news is we’re about to give you a lowdown on how to repair and replace a blown head gasket. We’re also going to let you in on some of the common mistakes others make when trying to fix it, as well as other tips worth mentioning.

Head Gasket Failure

Before learning how to repair it, it’s critical for you to know how to spot a faulty head gasket. There are various warning signs the problem already exists. One of the most common of which is overheating. You will also notice how your car takes a longer time to start or won’t start at all.

Other signs and symptoms you should watch out for are external leaks, your coolant and oil mixing as well as two or more of your cylinders malfunctioning. Once you’ve conducted enough tests to determine that you have a blown out head gasket, it’s time to repair or replace it.

3 Ways to Repair a Head Gasket

There are three primary ways to mend a head gasket. First is to provide a quick and temporary fix, which is a head gasket sealer. Second, fixing how the head gasket is installed by fixing the bolts and finally, replacing the head gasket with a new one.

1. Use of Head Gasket Sealant

Head gasket sealers come in all brands and quality, mostly in the form of paste, spray or glue. They cater to various car models whilst taking into account the number of cylinders present in your vehicle. It’s the most common way to fix a blown head gasket, as it holds the gasket in place as well as prevent any further seepage.

Using a sealer entails a number of benefits, which makes it a popular choice among repair shops and car owners. First, they’re a lot cheaper. Gaskets are in itself, inexpensive but it’s the effort of dismantling your car parts that will break the bank. The good news is sealers don’t require such a grueling process. This fix is also quick and rock solid, particularly if you have old cars that are close to living its full life.

Tips to Apply a Sealer

Here are a few things you need to keep in mind when applying a sealer:

  • Make sure the cooling system is clear, clean and free flowing.
  • Remove the thermostat and flush the cooling system using a flushing agent or a couple of gallons of water.
  • You can then fill the cooling system with water but make sure you leave enough space for the recommended amount of sealer (check label).
  • Pour the sealer gently while your engine is idling. Let it idle for 50 more minutes with the cap on.
  • Before installing a new thermostat, it’s crucial to let the engine cool completely.
  • Pour in the right amount of compatible anti-freeze afterwards.

There are a lot of brands to choose from, some of the best are Blue Devil, Steal Seal and Bar Leak. It’s just a matter of choosing which one is right and best for your vehicle.

2. Re-Torque of Head Bolts

Sometimes, it’s how the head gasket was installed in the first place that causes it to become faulty. When you’re an average DIY person, it can be tricky to make this work. That’s why it pays to learn more about it first.

This method is at its best, both a prevention and quick fix to hopefully saying goodbye to a damaged head gasket right away.

First and foremost, the head bolt should be 100% clean and undamaged. We never recommend re-using TTY (torque-to-yield) head bolts, as they are meant to be tightened in a certain way only once. It’s also best to clean and lubricate the bolts before installing them.

From here, use an accurate wrench to tighten the bolts in 3-5 incremental steps. Make sure that it is holding the right reading. Otherwise, it could mean trouble.

3. Head Gasket Replacement

If fixing the bolts and using a sealant don’t cut it, then it’s time replace the head gasket itself. This is where your wallet is about to cry a river but if you are experienced and confident enough to do a DIY, then follow the step-by-step procedure.

Steps in Replacing the Head Gasket

  1. Be sure to mark and label each components as you remove them. Be sure to disconnect the battery and drain the cooling system while you’re at it. If it’s the first time you’re doing this, you’re going to need that service manual beside you throughout the process.
  2. Check the evenness of the cylinder head and block. It should be as flat as the service manual indicates. While doing this, inspect for cracks as well. If the head or surface isn’t flat, it’s best to take it to the machine shop for resurfacing.
  3. Clean and inspect the mating surface. Never use anything that can compromise the metal and try not to scratch anything as you go along. Ensure there is no presence of oil, gas or grease.
  4. At this point, correct any torque readings as need be. You should also use compressed air to remove any stragglers. Any form of interference between your new gasket and other parts will compromise it.
  5. Place your new gasket with the right side facing up. Ensure all holes and openings line up with the cylinder head and block. Don’t use a sealant unless otherwise required.
  6. Position the gasket in place by using the right and new bolts, tightening the sequence and coating the bolt threads before installing. Remember to check and follow the torque reading instructions to the dot.
  7. Reinstall everything you removed, refill your cooling system and reconnect the battery.
  8. Crank the engine up and if you did everything correctly, you’ll be on your way to driving with a new gasket.

Repairing and replacing a blown head gasket takes skill, knowledge and experience. If you are not confident enough to do this on your own, it’s still best to bring it to a shop. However, if you are planning to do a DIY repair, check back on this guide to make sure you’re doing it right.

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