I’m changing the spark plugs on a 2005 Ford Expedition XLT, 2wd, automatic transmission. The spark plugs are notorious for breaking when you try to remove them. Is Deep Creep safe to pour into the cylinder head to soak and try to help loosen the spark plugs? Is the small amount of Deep Creep that I use on the spark plugs safe for my engine?
Thanks for the question, Serg.
First off, yes, Deep Creep is safe for that.
My advise for this style spark plug (I’ve done many in my 20+ years as an ASE Master Certified Auto Technician) is this:
Get the vehicle up to operating temperature and remove all the ignition coil assemblies. Once those are out of the way, saturate the spark plug area with Deep Creep and let it soak for at least 2 hours. After the soak time, slowly start to remove the spark plugs, going back and forth until you know that they are loose, then remove them. If they are going to break, they will break in the first 1/4 turn. Be patient and gentile. If they do break, you can purchase a removal tool at most parts stores.