It’s definitely a consideration for ej255 valve cover gaskets: gray 3bond is sparingly applied to the corners and convoluted areas as per the diagram in the FSM procedure.
There’s a lot of related considerations to successfully doing a valve cover job so I kept notes on the pitfalls:
Valve cover gaskets
Gray 3bond as per FSM instructions, don’t go overboard with the it.
In Australia, Burson stock 3bond products.
Inspect the rear lower corners for seated gasket after offering it up, but before tightening the bolts, failure to check will lead to a leak plus replacing the gasket.
Very carefully inspect the gasket is seated with torch & mirror before *nipping* up the location specific *shoulder* bolts in order as per FSM, again.
Prep with solvent or brake clean prior.
Ideally you’d let it sit and cure for a while on completing.
Iirc, the 3bond is required at the corners and convoluted areas, where it’s needed to help the rubber gasket seal.
If you have time, the trick is to offer up the gasket to the rocker cover, place it on a clean flat surface and let the 3bond set a little before offering it up to the head.
Using a torque wrench on accessible bolts will help calibrate your feel for nipping up the more inaccessible bolts.
The bolts have specific lengths and being shoulder bolts, specific locations on each head. The FSM has the locations and torque specs, or use a written diagram on cardboard and punch the bolts in their locations on the diagram.
Grind down a spare 10mm 12pt socket is in the plan for next time, plus assorted ring spanners.
Links to all year model market FSM workshop manuals:
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