How to gap plugs
Why change your spark plugs ?
You may not need to change your spark plugs, but as part of looking after your car and servicing it, it is useful to know how to take them out and inspect them. Perhaps give them a clean and check the electrode gap.
Wire brush for cleaning off deposits if you refit the old spark plugs.
So how do I change the plugs then ?
We have selected some videos below that best explain how to do this job.
We recommend having a look at all of them, and also have a look at your cars user/owner manual or Haynes Manual where you should find the correct electrode gap for your specific car.
What to look for when the plugs are out of the car.
Even if you are fitting new plugs
and not renewing the old ones, it is important to inspect the old plugs as this will tell you how good or bad your engine is running.
Here are some images with explanations ;
This is how a good spark plug should look.
The colour (Grey-tan to white) shows that the engine is running well.
This plug is showing excessive electrode wear.
It could cause an engine missfire when accelerating and could also cause difficulty starting the engine. Old age is normally the cause, should have changed it sooner.
Notice that the insulator has cracked and chipped off. A common cause is incorrect electrode gap, but sometimes it can be caused by engine detonation. Detonation can be due to incorrect octane fuel being used or incorrect ignition timing.Source: www.carbasics.co.uk