Comments on these plugs please.
 

Below are the six plugs I removed from my X this morning. I replaced them with the same kind (NGK Iridium). I am not a plug expert but these don't look too bad. Unfortunately I have no clue how long they have been in the X, they were there when I bought it. I do notice some carbon on a few, they all seem to have the tan color and no eroded electrodes. What do you all think?

If I had any brains I would have noted which cylinder each plug came from but I did not.

I probably would have put those back in. Nothing looks too bad maybe a little black around the outside but electrodes and insulators look ok and I would guess fairly new. Biggest difference seems to be from camera positioning/lighting/focus. For sure next time keep them in order when you take them out! ;)

Thanks for the input, I didn't think they looked too bad either. I just got the X about a month ago and I am slowly replacing/changing/renewing everything so I have a known baseline. The diffs, transfer case and tranny are lined up for tomorrow.

There lots of info on plug reading that can be used for engine performance analysis. I have few years in this field working for Champion Spark plugs in a previous life. Based on the images you have nothing to worry about. The carbon bild up on a few of the plugs, could be from lots of cold starts and short run drive cycles. If you look closely at those same plugs, the insulators, the porcelain type material in the center, are white meaning they are burning off the carbon at speed. All are burning clean so the ignition side is in good shape. I would do the following:
Replace with new (already done)
Run a container of injection cleaner through the system.
Change the oil
And take a road trip and enjoy the ride.

These plugs have about 80K on them.
Look at the prong side (not the Iridium side), you will see wear on the prong.

I posted some photos of Iridium plug "prong wear" in forum recently.

:iagree:

Below is a spark plug with 30K miles from my 1998 528i M52 engine.
Note the wear on the prong side.
Not a big deal, engine runs fine.
I regapped it back to spec.
These plugs now have about 60K.
I plan to change them at 70K or so.



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Thanks for the information. Did you gap to .045" or is that from erosion of the prong? Mine I left gapped at 030".

The recommended gap size is .032" for your application 05 BMW X5 3.0 engine
Use a fine wire gapping tool like the round one shown or a Bosch gap tool that has the calibrations for all applications.
As the gap wears, the energy to jump a wider gap is higher causing coil saturation (dwell time) to be higher, and the length of burn time as measured in mill secs, is shorter. All have consequences. Examples can be poor idle stability, tip in acceleration stumbles, high load (going up a hill) misfires. All will heat up plug wear, heat up coils, and shorten ign system life.
Bottom Line: Replace plugs as often as driving cycles demand 40-80k and use a little (a dot) Anti-seize on the treads, add a little Di-electric gel on the boot end that snaps on the plug. This two step process will allow you to remove the coil and plugs in the future as well as locking out moisture. Too much product is NOT better.
Plug manufacturers started to add a coating to some plugs to reduce the metal to metal transfers that happen when you screw in different materials together. Threaded Steel plug shells to aluminum heads for example. Adding a dot of anti-seize to the threads only enhances the abilty to seperate these two items in the future.
Oh add a little anti-seize to the back side of your alloy wheels will allow you to easily remove them for their annual cleanings, wash, IronX, clayings, and waxing too!

The 0.045" gap is from 30K driving.
I regapped it back down to 0.030" (not shown in the photo).

1+ to anti-seize (one drop on the spark plug, and yes I use anti-seize on wheel lugs and on the hub, where it meets the wheel).