Contrary to what many people believe, cylinder head replacement is not a complicated process. You can do it yourself, provided you know what is required and the steps involved. This article focuses on the procedure to follow when replacing a damaged cylinder head. To start us off, a look at why a cylinder head in a car may need to be changed.
Reasons for Cylinder Head Replacement
A cracked cylinder head can be welded, and a warped head resurfaced. Voids can also be filled with a sealing material. However, refurbished cylinder heads often do not last for long. There are also situations where cylinder head repair will not work. Such instances include:
- End of lifespan- Aluminum heads last for around five years, cast iron heads a few more. Besides the type of cylinder head material, allowing the engine to overheat can cause irreparable damage.
- Past resurfacing- There is a limit to the number of times you can carry out cylinder head resurfacing. Machining removes layers of metal. You cannot do it too many times.
- Extreme Cracking- you can fix cracks easily by welding them. If they are too large, cylinder head replacement could be the only option available.
- Excessive Warping– a badly warped head cannot be machined to create a flat surface. It can only be replaced.
Cylinder Head Replacement Procedure
You will need: a wrench set, ratchet and socket set, screwdrivers, new oil, coolant, rags, and new cylinder head.
PART 1: Cylinder head Removal
Drain the Coolant and Oil
Unscrew the radiator’s drain cap to release coolant out of the system. Remove also the oil pan’s drain plug to pour out the oil.
Remove the Engine Intake and Exhaust Manifolds
Deconstruct the intake and exhaust manifolds. Use a ratchet or wrench to separate them from the cylinder head. You will also need to remove the valve covers. Again, use the ratchet and socket set to do the job. Remove also the timing belt.
Detach the Rocker Arm
Next, remove the rocker arm. If the engine uses two heads, take out the two rocker arms.
Take off the Old Cylinder Head
Remove the mounting bolts following the correct cylinder head bolt removal sequence. The information about the sequence can be found in the car’s manual.
Next, lift off the old head from the engine housing. You may use a screwdriver to pry it loose at the edges.
PART 2: Install the New Cylinder Head
Mount the new head and replace the mounting bolts. Follow the manufacturer’s specifications for both sequence and the bolt torquing.
Replace the Components
Install the other parts following the order you used to remove them: rocker arm, timing belt, valve covers, and intake and exhaust manifolds.
Refill Coolant and Oil
Finally, replace coolant using a 1:1 ratio for water and antifreeze. Refill the oil pan with oil that your car’s manufacturer recommends.
Head Gasket Replacement
Before installing the new head, check the head gasket, if it is blown. You may need to replace it also. Blown head gasket symptoms include:
- Engine overheating too quickly
- Air bubbling in the radiator even after bleeding it
- Excess pressure in the coolant system and the radiator blowing out coolant
- White smoke coming out of the exhaust
- Coolant mixing with engine oil
Replacing a head gasket is not as intensive a process’s as repairing it. To change the gasket, follow the cylinder head replacement procedure up to the point where you have access to the gasket. Then, unmount it and put in a new one.
Cylinder Head Replacement Questions
Question: what is the cylinder replacement cost?
Answer: the cost amounts to $500 roughly. That includes the amount you spend to buy the component and installation expenses. If you carry out the replacement yourself, the only cost will be the cylinder head price, which would reduce the amount by up to $300 or more.
Question: how long does it take to replace a cylinder?
Answer: it depends on whether you are doing it yourself or have taken the car to a cylinder head repair shop. As a DIY project, cylinder head replacement time can be several hours.
Question: how do you remove a stuck cylinder head?
Answer: a cylinder head may be difficult to remove due to tightly mounted bolts. Here is how to remove stuck head bolts. Use a breaker bar to increase leverage, taking care not to use too much force. You may also use penetrating fluid to loosen the bolts.
After you have removed the bolts, here is how to remove a stuck cylinder head. Insert a screwdriver at the edges between the head and the cylinder block. Lift the screwdriver gently but with force to pry open the space between the two components.
Question: when should I replace a cylinder head?
Answer: bad cylinder head symptoms show that you need to replace the component. Most often, the signs also good indicate when to change the head gasket. Cylinder heads will serve you for five years or more, on average. The head gasket life expectancy is also around five years. That means the two parts may be replaced at the same time.
Question: can a fairly new cylinder head need replacing?
Answer: there have been instances where a cylinder head only served for a short time and required repair or replacing. Most of the time, the problem happens during the manufacturing process of the cylinder head. Impurities or gases in the casting material cause spaces within the head. The voids lead to what is called porous cylinder head.
Question: how hard is it to replace a head gasket?
Answer: replacing a head gasket can be a cumbersome process. You have several components to remove, including the cylinder head. If the gasket is damaged, that could also mean some other parts to fix.
Question: how much does it cost to replace a cylinder head gasket?
Answer: the amount depends on your locality and type of car or engine. Head gasket replacement cost can go up to $1000. While the price of the gasket may not be that high, it takes a lot of time to replace. You are dismantling almost half of the engine, which makes the process labor-intensive. Head gasket repair costs even more.
A damaged cylinder head can be repaired. However, there is no point in fixing a head whose lifespan is over. It will still crack or warp almost immediately after. Cylinder head replacement offers a better solution. But then, not many people understand how to do it, or even when. We believe this article answered questions you had concerning why and how to change a cylinder head.