Gasket removal, especially on multi-layered steel (MLS) head gaskets may leave behind a residue that is difficult to remove from the sealing surface. Effectively immediately, two new cleaning products are released to the field for use in removing gasket and oil residue from aluminum cylinder heads. These products are available and are recommended whenever a cylinder head is removed from the engine. The purpose of these cleaners is to ensure a safe cleaning process is available which will not threaten the integrity of the sealing surface of the head.
If petroleum residues are left behind neither the MLS gasket nor RTV will adhere to metal and bond properly as designed. In this scenario, a gasket or RTV bead will only act as a "compression" gasket, which is insufficient to seal the area. Preparing the surface with the products listed herein will leave a clean, dry surface in which new replacement gasket can bond with the metal.
"Motorcraft Silicone Gasket Remover" (Motorcraft part number, ZC-30) is a softening and loosening agent which attacks RTV and residue left behind by a multi-layered steel gasket. It is packaged in a pliable tube in gel form. It sits on the residue build-up breaking down the bond between the RTV and the metal by working in a more concentrated form.
The second product which is used as a follow up to the Gasket Remover is "Motorcraft Surface Prep" (Motorcraft part number, ZC-31) and is packaged in a small can with applicator brush. This is used as a surface preparation to rid the sealing area of oil, coolant residue and residual RTV before installing the gasket and before RTV is applied to tee-joints.
Surface Cleaning And Preparation:
This is a crucial step in the success of a head gasket repair. The set-up time to soften RTV will vary, depending on the thickness of the residue left behind. Remove as much of the old material as possible with a plastic or wooden scraper without damaging the aluminum with score marks or depressions. Coat the surface liberally with Motorcraft Silicone Gasket Remover (ZC-30). Allow the softener to act on the remaining residue and remove it with plastic or wood scrapers only. Next, coat the surface with Motorcraft Metal Surface Prep (ZC-31), let sit for several minutes (depending on amount of residue) then wipe clean with a lint-free cloth. This will remove any remaining deposit or residue and prepare the surface to receive RTV and the MLS gasket.
Use of power sanding, grinding, and buffing equipment is unauthorized for warranty repairs. Use of manual grinding and scraping aids which include sandpaper, razor blades, or metal scrapers is not authorized. Resurfacing of aluminum machined head gasket surfaces is also unauthorized for repair by Ford Motor Company.
Plastic or wood scrapers in conjunction with the new gasket remover and surface preparation products identified in this bulletin are the only products allowed for servicing Ford aluminum cylinder heads.
For older engines using composite gaskets it is recommended that a steam application (power steam jenny or dip tank) be directed at the hard residue.
This will re-hydrate the material and soften it sufficiently to use a plastic or wood scraper for removal. It is still recommended to apply a coating of ZC-31, Motorcraft Surface Metal Prep, to rid the surface of all coolant and oil residue. RTV and silicone bead gaskets will not bond to the surface if there is a film left behind.