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Spark Plugs Replacement
Typical Cost: Low
Mobile Repair? Yes
Typical Lead Time: 2 - 24 hours depending on mechanic availability
What does a spark plug do?
The engines spark plugs provide the spark in the combustion chamber to detonate the fuel and air mixture in order to force the piston back down and thereby rotate the crankshaft.
How does a spark plug work and what are the components?
The spark plug is screwed into the engine’s cylinder head and protrudes in the cylinder bore. When the engine ECU deems that the piston is in the correct position for the fuel/air mix detonation (timing), it will send a signal to the coil pack that controls the voltage feed to the spark plug. The coil then amplifies the voltage and sends it to the spark plug and forces an electric arc to occur between the electrode and the earthing body of the plug.
This arc (spark) ignites the fuel.air mixture and causes an explosion which forces the piston back down and thus rotating the engine.
Typical symptoms that require spark plugs to be replaced.
The main symptoms that can occur when there is a faulty spark plug are;
- When starting the car is problematic.
- When the engine cuts out after starting.
- When the engine does not run smoothly (the engine misfires).
- When the car vibrates excessively.
- When the 'Check Engine' light on the car's dashboard is on.
What happens during a spark plug replacement?
Changing spark plugs is a routine repair for all mechanics and can be done both kerbside as well as in the workshop, providing it is safe to do so.
Whilst there are variations between manufacturers, the basics are pretty similar.
The mechanic will;
* Read the ECU for possible fault codes related to the ignition system.
* Inspect the ignition system and spark plugs.
* If necessary, replace the full set of spark plugs
* Advise if any other parts need to be replaced.
* Check if the ignition system works correctly again and will test drive the car.
What does this repair cover?
Unless otherwise stated, the quote for your spark plugs to be replaced will cover;
- The cost of the spark plugs
- Coming to you
- Fitting of the parts
- Disposal of the old parts (unless you request to keep them)
- VAT (if applicable)
- 12 months parts and labour warranty
What to search for on the ClickMechanic site?
Spark plugs replacement
Associated repairs
Ignition coil replacement
Ignition coil replacement (all)
How much does it cost to have the spark plugs replaced?
The cost of replacing your spark plugs depends on your car and which parts your car's manufacturer recommends.
Find out what you could save by visiting ClickMechanic
https://www.clickmechanic.com/bookings/car
FAQ’s
Can I supply my own parts?
No, we will not fit customer supplied parts unless they are a brand new item, purchased from a dealership with the receipt as proof of purchase. There is no flexibility over this due to insurance and warranty issues.
What happens if the mechanic finds that the spark plugs do not require changing and the problem is due to another issue?
In this scenario, the mechanic will provide a no obligation quote for the correct repair. Should you accept this, the mechanic can alter the booking accordingly. If you decide not to go ahead with the alternative repair, the mechanic can change the booking to a call out and diagnostic booking and charge according to the time spent with the vehicle and call out.