Time to step it up. How to change a Head Gasket: HowTo blog #5

A common problem that I see in older cars is they tend to have old and worn out Head Gaskets. While replacing a head gasket is by no means an easy fix, having one replaced by a mechanic can cost between $1100 and $1500, so if done correctly you can save thousands in automotive repair bills. Before we begin, I think you should know what you are going to be doing beforehand. The head gasket, as its name implies, sits between the head of the engine and the engine block. The size of tools you will need varies from manufacturer to manufacturer, but a basic set of sockets, a ratchet, and an extension, a torque wrench, and a plastic scraper should be enough to do the trick. As for parts, you will need a Valve Cover Gasket(s) depending on engine size, Head Bolts, and Head Gasket(s) depending on engine size

Basic 4-Cylinder Head Gasket

The first thing you need to do to replace a head gasket, is to remove all of the extra stuff that is in the way. Again this varies from manufacturer to manufacturer, but the most common things that need to be removed are sensor plugs and wires, spark plug wires, spark plugs, throttle cable, alternator, exhaust manifold ( and heat shield if equipped), and depending on the type of engine, (over head cam or over head valve) you may need to remove the serpentine belt as well. you need to make sure that there are no wires, or parts covering the valve cover and that no parts can get in the way after removal. Depending on the size of engine, ( I-4, L-6, V-6, V-8) you may need to remove parts covering two valve covers.

Engine Bay of a Basic I-4

The next step is to remove the Valve Cover and Valve Cover Gasket. If the Valve Cover Gasket does not come off in one piece, use the plastic scraper to remove what you can't get off by hand. Here is where the two types of engines spit off for a bit, If you have an Over Head Cam engine then you need to remove the camshaft. Before you do this, make sure you take note of where the notches are on the camshaft pulleys so you won't get it out of time when you are putting it back together. there should be one notch on each pulley that lines up with a notch on the crankshaft pulley. After that is done you can remove the camshaft(s) by unbolting and removing the camshaft baring, making sure to note which baring goes where. If you have an over head valve engine this part is going to be much easier, but much more tedious depending on how many cylinders your engine has. You need to unbolt every rocker arm and pull out every push rod (usually 2 to 4 of each per cylinder).

Over Head Cam Setup

Over Head Valve Setup

Last step is to remove the Head and the Head Gasket. To do this, remove the head bolts and throw them away. Most head bolts can not be used twice and will likely snap if torqued down again. This is why it is recommended that you get new head bolts every time you take the head off of the engine. If the head gasket does not come off in one piece, use the plastic scraper to get off what you can't get with your hands. You should be down to the engine block and should be able to see the top of the pistons at this point.

Engine Block with Head Removed

I am going to stop here, come back next Saturday for the rebuild HowTo blog. Until then, if you have any questions, post them down in the comments and I will try to answer as quickly as I can and to the best of my knowledge, and as always, if there is something you want me to cover, leave it down in the comments as well.