All fuel engines have spark plugs to ignite the combustion that drives the engine. Diesel engines don’t have any spark plugs; they ignite “automatically”.
There are spark plugs in all engine cylinders, one for each cylinder. A 4-cylinder engine, therefore, usually has 4 spark plugs.
The plugs are located inside the cylinder head, which is located on top of the engine block. They make sure to ignite the spark at the right moment, which is when the pistons almost reach the top of the cylinder. At this point, the mixture of fuel and air has been compressed enough for combustion to be possible with a spark.
The smaller explosion then presses the piston back down in the cylinder, which in turn makes the crankshaft rotate. The crankshaft is basically what drives the car’s many parts.
It’s the spark coil - or ignition coil - that makes sure the spark plugs are “activated” at the right time. The ignition coil is connected to the timing belt, which makes sure to align the spark plugs with the pistons’ movements. This results in continuous ignition!
Some bigger Mercedes or Alfa Romeo models might have two plugs to each cylinder to ensure a more accurate ignition and higher efficiency; this is called a twin spark.
If you make sure have your car serviced with regular intervals, adhering to its service manual guidelines, the spark plugs will be changed every 4th year or so by the mechanic. That’s part of the service inspection, and you just have to pay for the spare parts themselves.
However, if you experience any trouble starting your car, you might check up on these things:
Some car owners ask mechanics if they can do with just cleaning the spark plugs. But it’s not really a question of how to clean spark plug. The cost and ease of replacement means that this is always a more viable option!
If you are in doubt about whether your spark plugs are faulty, you can ask if your mechanic can use a spark plug tester. They will then let you know what needs to be done.
If you want to try and change the spark plugs yourself, it’s easy to buy good quality plugs online. Iridium spark plugs are stronger than platinum and have a higher melting point.
| Make | Compare and save* | You save on average* | Ratings | |
|---|---|---|---|---|
| Audi | £139 | 25% |
5.0
(6)
6
0
0
0
0
Read the reviews
|
|
| BMW | £139 | 28% |
3.5
(2)
1
0
0
1
0
Read the reviews
|
|
| Citroën | £172 | 23% |
5.0
(1)
1
0
0
0
0
Read the reviews
|
|
| Ford | £152 | 24% |
4.7
(10)
8
1
1
0
0
Read the reviews
|
|
| Mercedes-Benz | £135 | 24% |
4.8
(4)
3
1
0
0
0
Read the reviews
|
|
| Mini | £173 | 30% |
3.7
(3)
2
0
0
0
1
Read the reviews
|
|
| Peugeot | £154 | 25% |
4.5
(8)
7
0
0
0
1
Read the reviews
|
|
| Renault | £183 | 24% |
5.0
(1)
1
0
0
0
0
Read the reviews
|
|
| Vauxhall | £138 | 25% |
5.0
(14)
14
0
0
0
0
Read the reviews
|
|
| Volkswagen | £156 | 26% |
4.8
(8)
7
0
1
0
0
Read the reviews
|
|
| Make | Save on average* | |||
|
Audi
5.0
(6)
6
0
0
0
0
Read the reviews
|
£139 / 25% | |||
|
BMW
3.5
(2)
1
0
0
1
0
Read the reviews
|
£139 / 28% | |||
|
Citroën
5.0
(1)
1
0
0
0
0
Read the reviews
|
£172 / 23% | |||
|
Ford
4.7
(10)
8
1
1
0
0
Read the reviews
|
£152 / 24% | |||
|
Mercedes-Benz
4.8
(4)
3
1
0
0
0
Read the reviews
|
£135 / 24% | |||
|
Mini
3.7
(3)
2
0
0
0
1
Read the reviews
|
£173 / 30% | |||
|
Peugeot
4.5
(8)
7
0
0
0
1
Read the reviews
|
£154 / 25% | |||
|
Renault
5.0
(1)
1
0
0
0
0
Read the reviews
|
£183 / 24% | |||
|
Vauxhall
5.0
(14)
14
0
0
0
0
Read the reviews
|
£138 / 25% | |||
|
Volkswagen
4.8
(8)
7
0
1
0
0
Read the reviews
|
£156 / 26% |
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