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2002 Chevrolet Silverado, Platinum vs. iridium spark plugs?

Recently bought a 2002 Silverado 2WD with 104K and engine does not run smoothe when idling, not bad though. Haven’t pulled plugs yet but figured I’d start there. OEM is iridium but most choices at parts store are platinum. Any recommendations or must do’s and dont’s?

If OEM is iridium, I would hesitate to change that, unless I intended to use a much shorter interval on plug changes. Doesn’t Chevrolet spec either 100K or 120K intervals on the iridium?

Stick with what the manufacturer used.

Besides,. irridium being some eight times harder than platinum it’s much less subject to erosion from the discharges and provides a strong spark longer.

I would use the exact same plug that the engine was built with. If necessary, go to a chevy dealer parts deptartment.

Be sure to change the plugs when the engine is cold. If they are very difficult to remove, use penetrating oil. Put antiseize on the new plugs and torque them to spec.

Who told you the OEM plugs were Iridium? I’m roughly 97% sure that the OEM plugs are platinum. No way the GM bean counters would spring for Iridium plugs from the factory. I’m not even sure if Iridium plugs were even widely availible back in 2001/2002.

Iridium, double platinum, platinum, copper…pay me now or pay me later.
cost less -replace more often…cost more - replace less often, it all comes out in the wash.

Best to stick with o.e. recommended for proper operation, therefore avoiding unforeseen problems which will then cost even more.

ridium, double platinum, platinum, copper…pay me now or pay me later.
cost less -replace more often…cost more - replace less often, it all comes out in the wash.

Be careful about using fancy plugs to give you longer life on the plugs. I would not leave a plug in over the recommended change time because they can become frozen in the engine and cause a lot more problems than just using OEM and changing them as instructed in the owner’s manual.

I have an 03 blazer and was looking to replace plugs at 90k, 100k recommended by manual, and the parts guy at a nationwide chain said I’ll order the GM plug, we have had too many sad tales of people having to put the old plugs in after buying something else to get back here to complain after buying a supposed replacement. I was not used to $8.67 per plug but bought the GM plugs. The part number I ordered had been superceeded by a new part number but they are doing well. Moral of the story don’t go for the glitz, splitfire whateveridium, go for OEM parts.


As to the part number, the replacement plugs listed by even the OEM manufacturer will often be a slightly different part number. In my tC, the one character that varies is (on the originals) a “special elactrode” designation that cannot be bought. The reason is that Toyota has “spec controlled” the drawing, a common design practice. The exact replacement comes with the same irridium electrode, but under NGK’s part designation.