Spark Plug Condition

Maintenance/Repairs
1

I’ve just changed the plugs on my '91 LeSabre, with the 3800 V6. All six plugs came out in the same condition: a white kind of powder on the electrode and insulator. See a pic here: http://www…G_9828.JPG



When compared to the pictures in the Haynes manual, it doesn’t quite look the “normal” or “worn” pics, but more like the “too hot” pic. Is there anything to look into at this point? The engine was running perfectly before the change, and fired up just fine with the replacement plugs. The plugs that came out were NGK V-grooves. The new ones are basic AC Delcos.

2

There can be several reasons for a whitish color on the plug tips; gasoline additives, air leak, coolant into the combustion chambers, or ignition timing that is too far advanced. The latter is not likely and I’m also leaning against coolant into the combustion chambers since all 6 are affected.
An air leak could cause a rough idle, surging, or lowered fuel economy depending on the source and severity of the air leak. This could be verified with a vacuum gauge.
Offhand, this may be more related to the gasoline blend and probably is not something to worry about at this point.

Those plugs are definitely pure junk and should have been changed long ago though. JMHO and hope it helps.

3

Thanks ok. I bought the car in March '06 and hadn’t changed the plugs until now. Don’t know the previous history either. Figured I’d finally do it before it started messing up. The engine has been running perfectly, so at this point I don’t think I’ll worry about anything else. Good idle, no surging, fuel economy’s good.

4

To me it looks like it might be just ash buildup from plugs that have been in an engine using a normal small amount of oil for a very long time…well past the recommended change interval.

There are a number of sites that have comparison photos. Try googling “reading spark plugs”.

5

just drive the car it is not a $80.000 car enjoy it

6

That’s ash deposits. This comes from either the gas or from oil burning.

If all the plugs look the same, I’d say it’s from the gas you’re using.

Tester