I'm in the process of giving my C4 a Tune-up, I need opinions on Spark plugs... AC Delco are the most logical choice . But  from what my  local parts folks say ,is that I can only use platinum plugs on Aluminum heads.....is there any truth to that?  The Cap & Rotor seems to be a tight fit , Is there anything I need to removed other then the  Aluminum cover?   Also I plan on changing the fuel filter .....Were would it be @ under the chassis & how hard is it to get too & swap? Any and all Advise & opinions will be  appreciated

Thanks


|UPDATED|5/2/2013 10:33:16 PM (AZT)|/UPDATED|

What year is she?

|UPDATED|5/3/2013 7:18:11 AM (AZT)|/UPDATED|

The material the head is cast from don't know what material the center electrode of the sparkle plug is made from....nor does it care.
You can use platinum plugs if you want, but it is NOT mandatory....someone is just trying to sell you higher priced plugs....that's all.

The fuel filter should be on the passenger side, bolted on the inside of the "frame", just behind the pass side front wheel. You'll have to jack the car up to get to it. Be sure to use jack stands before getting under the car. 

Whatever plugs you use is up to you.  Regardless of heads (aluminum or iron) use anti-sieze compound on the threads.  Mandatory on aluminum but just smart on iron.

Mike

If you use anti-seize on the plugs, be very careful about getting it on the taper or gasket. It may make the plug come loose.

I work on boats and yachts. I've removed thousands of plugs from engines. There are various combinations of plug shell material/head material. Some are more prone to corrosion and seizing than others. Here's a list in descending order of combinations most likely to have seizure problems. I don't bother with anti seize on the last two. They never seize.

Stainless plugs in aluminum heads.
Steel plugs in iron heads.
Steel plugs in aluminum heads.
Stainless plugs in iron heads.