spark plugs problem

[momo-yx]

what causes this problem ???
this brown color in all 4 plugs
Is it big problem or not ???

[mr_miles]

I've always thought it's burnt oil, but i could be wrong. is your engine clean or does it have grime?

[barryware]

that is the result of hot gas's leaking between the metal spark plug body and the ceramic center part.

It is normal and should not be an area of concern but your pictured plugs have more discoloration than I have seen before. It is seen more and more on the "high mileage" spark plugs because they are in service much longer compared to older designs.

How many miles are on the plugs?

[Geoff Peace]

Originally Posted by momo-yx

what causes this problem ???
this brown color in all 4 plugs
Is it big problem or not ???

This is caused by minute oil particles suspended in the atmophere sticking to the plug because of high voltage. No gas is escaping and it is no detriment to the performance of the plug. If it is very bad (much worse than yours) the spark can track up the face of the insulator, known as corona discharge. Can best be seen as blue flashes in the dark.
Regards Geoff Peace.

[momo-yx]

Originally Posted by mr_miles

I've always thought it's burnt oil, but i could be wrong. is your engine clean or does it have grime?

I'll show you picture, give me some time

Originally Posted by barryware

that is the result of hot gas's leaking between the metal spark plug body and the ceramic center part.

It is normal and should not be an area of concern but your pictured plugs have more discoloration than I have seen before. It is seen more and more on the "high mileage" spark plugs because they are in service much longer compared to older designs.

How many miles are on the plugs?

5000 miles or less (Always on hi speed )

Originally Posted by Geoff Peace

This is caused by minute oil particles suspended in the atmophere sticking to the plug because of high voltage. No gas is escaping and it is no detriment to the performance of the plug. If it is very bad (much worse than yours) the spark can track up the face of the insulator, known as corona discharge. Can best be seen as blue flashes in the dark.
Regards Geoff Peace.

I think you mean it's not big problem

[A-Dingo-Ate-My-Baby]

Originally Posted by Geoff Peace

This is caused by minute oil particles suspended in the atmophere sticking to the plug because of high voltage. No gas is escaping and it is no detriment to the performance of the plug. If it is very bad (much worse than yours) the spark can track up the face of the insulator, known as corona discharge. Can best be seen as blue flashes in the dark.
Regards Geoff Peace.

I was waiting for this post.

if it was blow-by, it'd have carbon black on it.

[Geoff Peace]

It is not a big problem because it is no problem at all! It is worse on cars where the plugs are buried deep in the engine which is most cars these days, and covered either by HT lead caps or as in the case of the Yaris coilpacks. Also as stated the service interval for plugs is being extended, in some cases to 100,000 miles whether plugs are serviceable at this mileage remains to be seen.

Regards Geoff Peace

[momo-yx]

Originally Posted by Geoff Peace

It is not a big problem because it is no problem at all! It is worse on cars where the plugs are buried deep in the engine which is most cars these days, and covered either by HT lead caps or as in the case of the Yaris coilpacks. Also as stated the service interval for plugs is being extended, in some cases to 100,000 miles whether plugs are serviceable at this mileage remains to be seen.

Regards Geoff Peace

thank you so much