Even the best gasket cannot seal a poorly prepared surface. Many gasket leaks after a repair come from surface preparation, not from the gasket itself. These best practices apply to head gaskets, intake and exhaust manifold gaskets, and most other engine gaskets.
1. Remove Old Gasket Material Carefully
Remove all old gasket material and sealant without gouging the surface. Use scrapers and gasket removers that are suitable for the surface material. Be cautious with abrasive discs, especially on aluminum: they can remove metal unevenly and leave abrasive debris that can enter oil and coolant passages.
2. Check Flatness
Use a precision straightedge and feeler gauge to check sealing surfaces for warpage in several directions. Compare the results to the manufacturer’s specification. Surfaces that are out of specification should be resurfaced by a machine shop.
3. Confirm the Surface Finish
Some gaskets, including multi-layer steel (MLS) head gaskets, require a specific surface finish to seal properly. Confirm the requirement in the gasket instructions or service information, particularly after machining.
4. Clean the Bolt Holes
Chase threads to remove dirt and old sealant, and make sure blind bolt holes are free of oil and coolant. Fluid trapped in a blind hole can prevent the bolt from reaching the correct clamping force and, in some cases, can damage the block.
5. Clean and Dry Before Assembly
Wipe sealing surfaces clean and dry with a solvent that leaves no residue. Do not apply sealant unless the gasket or engine manufacturer specifies it, and use only the type and amount specified.
6. Follow the Torque Procedure
Tighten fasteners in the specified sequence and stages, using the specified torque values or torque-angle method. Replace torque-to-yield bolts when the manufacturer requires it.
Evergreen Gaskets and Sealing
Evergreen gaskets are manufactured by an IATF 16949-certified sealing manufacturer and are configured by application. Use the Evergreen eCatalog to find gasket sets and sealing components for your engine.
