Do It Yourself Changing Your Cars Spark Plugs
If you drive a car with a gasoline engine, the spark plugs will eventually need to be changed. Diesel and electric engines do not have spark plugs, so the owners of those vehicles will not need to worry about this maintenance item. Older cars, made in about 2000 and earlier, will need the spark plugs replaced more often. The interval is approximately every 30k-50k miles. Most cars built after 2000 don’t need the spark plugs replaced as often. Most can go up to 100k miles before needing their spark plugs replaced.
If you don’t replace the spark plugs at the correct interval, misfires and pinging can occur. Misfires will cause unburned fuel to go through the engine into the catalytic converters and cause them to wear out prematurely. This also causes poor fuel economy and wasted money. Pinging, or preignition, , can cause holes to form in the pistons which usually means engine replacement if left for too long.
Replacing the spark plugs on some cars can be done fairly easily, while others can be extremely difficult. Most four-cylinder engines are pretty straight forward. The spark plugs are usually easy to get to, and the job can be accomplished in about 45 minutes. Most V-6 and V-8 engine spark plug replacement jobs will take more skill. Many times, other components will need to be moved out of the way to get to the spark plugs. In some severe cases, the engine may have to be partially lifted or completely removed to perform this task.
If you are going to do this job yourself, make sure you consult a workshop manual to ensure that the job will be done right. Before you start, make sure the new spark plugs are the correct part. Spark plugs come in different lengths and if the incorrect part is installed, severe engine damage can occur when the engine is started. Make sure the engine has cooled down before removing the plugs or the cylinder head could be damaged if the spark plug hole threads detach and come out with the spark plug. When this occurs, the only proper fix is to replace the head, or use a special kit that is made for repairing this issue. Many Ford truck engines can have this problem, or their spark plugs break off in the head.. This should definitely be taken to a qualified repair shop for a proper repair.
After you get the spark plugs out and you have made sure you have the correct replacement plugs, apply a small amount of anti-seize to the threads and thread the new plugs in by hand to make sure they are not cross threaded. Check the manual for the correct torque value. You’ll need a torque wrench for this part. If the plugs are under torqued, they can spin loose and cause misfires. If the plugs are over torqued, they can strip out the threads in the cylinder head and cause damage to the point where the head has to be replaced, which is very costly. if the car has spark plug wires, make sure they are installed in the correct order. If the car is equipped with coil-on plugs, it’s much harder to mix these up, although I’m sure someone has done it.
Follow these tips and you’ll be on the road to a better performing, more economical engine.