Spark plugs are essential to the proper functioning of your gasoline vehicle’s engine. They play a catalyst role since, thanks to their electrodes, they cause a spark which allows the explosion in the engine thanks to the combustion of the mixture of air and gasoline.
Each spark plug has a different thermal degree, you need to know the correspondence of the spark plugs depending on the brand. In this article, we explain what the thermal rating of a spark plug consists of and list a spark plug correspondence table.
What does the thermal degree of a candle consist of?
Spark plugs have different thread types depending on their thermal rating . They have two main missions: to dissipate the heat produced during combustion between the air and the fuel and to burn the residue present in the system after the explosion.
The thermal degree, often also called heating value , must be calculated according to the type of engine your vehicle is equipped with. Thus, it is with this thermal degree that it is possible to define how the spark plugs will be used and therefore to choose the corresponding models. However, if you install spark plugs with the wrong thermal rating on your engine, two situations can occur:
- A spark plug with too high a thermal rating : it will destroy very quickly and, when melting, will fuse with the engine piston. If this happens, engine parts such as the piston or valves can become seriously damaged, even leading to complete breakdown of your car’s engine;
- A candle with a thermal degree that is too low : it will not be sufficient to cause combustion of the air and gasoline mixture within the combustion chamber . You will have difficulty starting your vehicle and you may possibly notice excess fuel consumption .
Spark plug mapping table

This spark plug correspondence table allows you, with its reference number, to find an equivalent among the brands NGK, Beru, Bosch and Champion.
Reference number | NGK | BERU | BOSCH | CHAMPION | EYGUEM |
---|---|---|---|---|---|
07450 | A7 | 18-4A1 18-4A2 18-5A 18-5AS 225/18 225/18S 240/18 | M4A M4A2 M4AC M5A M5AC M7AC | K9 | K750M |
07451 | B4H | 14-10A 95/14 | W9A W9AO W10A W10AC W12A | L14 | 200 502 MOTORCYCLE |
07815 | B4-LM | — | W9E0 | J17LM | — |
16555 | B5ES | 14-8C 14-9C 125/14/3 145/14/3 | W8C W8CC W8CO W8CP | N288 | 450L |
07452 | B5HS | 14-8A 145/14 | W8A W8AC W8AO W8AP W9AC W9ACO | L90 L288 | 50M 500M 705S MOBY MOTO |
07460 | B6HS | 14-7A 14-7AU 14Z-6A2 175/14 190/14Z D175/14 | W7A W7AC W7AO W7AP | L7J L9J L10 7 L82 L82C L85 L86 L86C L86CC | 70M 75M 700 700MOTO 755 755MOTO 755M 775X |
07453 | B6S | 14-7E 175/14/5 | W7E W7EC W7EP W8E W8EC | H03 J6 J6C J6J J7 J7J J8 J8C J8J UJ6 UJ8 | 500CM 700CM 755CM |
07471 | B7HS | 14-4A2 14-4AU 14-5A 14Z-7AU 225/14 240/14 | W4C3 W5A W5AC W5AP | L4J L5 L77J L77JC L78 L78C L81 UL4J UL81C UL81J | 850 850 MOTORCYCLE |
07454 | B7S | 14-5E 225/14/5 | W4E2 W5E W5EC W5EP | J4 JAC J4J J5 UJ4J UJ81C UJ81J | 1000CM |
16556 | BCPR5ES | — | FR8DC | RC12YC RC14YC | RFC52LC |
07817 | BCPR6ES | — | F6DCOR F7DCOR FR6DC FR6DP FR7DC FR7DP FR7LC2 | RC9Y RC9YC RC9YCC | — |
07455 | BM6A | — | WS7E WS8E | CJ8 CJ11 CJ86 | 500CT 755CJT |
07457 | BM6F | — | HS8E | DJ7J DJ8J | 500CJR 755CJT |
07456 | BM7A | — | WS5E | CJ3 CJ4 CJ6 | — |
07461 | BM7F | — | HS5E | DJ6J | — |
07781 | BMR4A | — | WSR9E | — | — |
07462 | BMR6A | — | — | RCJ8 | — |
07470 | BMR7A | — | — | RCJ6 | — |
07782 | BP5ES | 14-8D 14-9D 125/14/3A W8DCO 145/14/3A 14-6D 14-6D1 | W8D W8DC W8DP N11YCC W9D W9DC W9DP W6D W6D1 | N11Y N11YC N12Y 580LS N12YC N12YCC N13Y N14Y N8Y | 550LS CLNY C52LS 600LS |
How much does it cost to change the spark plug?
The price of changing a spark plug may vary depending on the type of spark plug your vehicle has and its model.
On average, it costs between €45 and €60 with parts and labor included to change a single spark plug. If several spark plugs need to be changed , this price range will have to be multiplied.
You now know the thermal rating of a spark plug and what the different correspondences are from one model to another brand. If the spark plugs in your vehicle seem defective, you must intervene quickly to avoid damaging the engine or any other part linked to the combustion chamber.