Spark plug damage ?.

Hi all,

Just lately i noticed my car emissions smells a bit strong while sat in traffic with the windows open.
So thought i would give it the once over today.

I removed all the Spark plugs and inspected them. (NGK BP7EFVX) Platinum.
They were only fitted approx 2000 miles ago.
I noticed at the bottom end of the ceramic there is a small amount of brown burning. Or at least what looks like burning.
The platinum tip and the electrode gap were all spot on.

I refitted all the plugs and took it out for a drive to bring it up to max temp.
I checked the mixture and got 1.20% at idle, and exactly 1% CO when the Breather cap is removed. So the idle mixture appears spot on.

Any ideas what would cause the browning of the ceramic insulator after so little miles ?. Should i replace them again ?.

Cheers,

Sounds fine to me!

Where is the part number for the washer jets you fitted??

Hi Paul

Have a look at this link to NGK
http://www.ngkntk.co.uk
Go to Technical Centre - spark plugs - corona stain

By the way the car sounded nice when pulling away from the French peage on the way down to lemans

regards Derek Gordon

LOL I'm a rocket scientist!!!!

Normal condition

An engines condition can be judged by the spark plugs firing end appearance. If the firing end of a spark plug is brown or light gray, the condition can be judged to be good and the spark plug is functioning correctly.

Bl00dy h3ll I shold be charging for my replies!

.. well now, to be technically correct, the colour indication is most accurate at the root of the ceramic

But you can have an A+ for good behaviour

Ahh so its a Corona Stain.. apparently caused by oil particles sticking to the insulator. Nothing to worry about then....


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A brown stain - often mistaken for gas leakage - is sometimes observed in a ring around where the insulator joins the metal shell of the spark plug. This discolouration is generally called Corona Stain and is the result of oil particles present in the air around the engine adhering to the insulator surface.



The Corona Stain is often seen on spark plugs that are installed deep into the engine such as on many four valves per cylinder engine applications. This is because oil particles are not blown away by air circulating around the engine compartment and thus adhere to the insulator surface. It is important to understand that Corona Stain causes no deterioration to the function of the spark plug.
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(Simon) I cannot find that invoice for the Washer Jets.. So ive sent an email to my local Dodge Parts Dept.. Should have a number for you soon.
I was thinking of getting another set for the wifes Astra. At under £10 its a cheap and usfull mod.

Sounds fine to me!

Where is the part number for the washer jets you fitted??

Simon, as requested.

Dodge Nitro, windscreen washer jet.
55157319AA ...2 .............NOZZLE.
£8.74.

Availible from any UK Dodge dealer.
Apparently, its the same washer jet on ALL current Dodge models.
It produces a fine spray in a fan pattern that covers the entire windscreen. Rather than a jet blasting in one spot.

COOL!

Thanks for that!