spark plugs

[benny 61]

Hi all, how do spark plugs deteriorate, and how quickly.
Is it mainly a milage thing or will they go off with age also.
Any spark plug experts

[LuS1fer]

Take them out and inspect them, at the very least, otherwise you risk them corroding in there and snapping. It depends on the plug - some will last 80k, some are recommended to be changed every service. Inevitably, having a look is the way forward.

[P Nuts]

The best advice I could give, is just spend some time removing them and checking yourself, it would be hard to say exactly. I normally change my every service to be honest

[lufbramatt]

the electrodes burn away, making the gap too big to get a reliable spark. Incorrect mixture, incorrect gap setting or the wrong grade plugs will accelerate the rate at which they degrade. Bigger gap means the spark needs a higher voltage to jump the across, putting more load on the ignition components.

You can get a good idea of how well the engine is running by looking at the colour of the plugs. they should be a nice uniform, matt caramel brown colour. Any black oily deposits or a white glazing means something is up.

A broken electrode floating around inside a cylinder can do a lot of damage. I've seen pics of a ford cosworth engine with a destroyed piston and exhaust value due to a plug dropping an electrode. Worth checking them if in doubt.

ETA: http://www.clubgti.com/showthread.php?266022-2-0L-...

Edited by lufbramatt on Thursday 26th September 08:49

Edited by lufbramatt on Thursday 26th September 08:51