Sealing surfaces of the crankcase and cylinder heads are provided with
an 0.8 mm thick silicone layer (Loctite 5900) during standard factory
assembly. Silicone sealant should be applied during repair assembly
only if sink holes exist in the sealing area.
When cleaning sealing surfaces of the factory applied silicone sealant,
during cylinder head reassembly, extreme care must be taken in order
not to scratch or damage the sealing surfaces.
DO NOT use any gasket removal materials that are abrasive. Failure to
follow this procedure could result in severe and permanent engine
Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.