I am taking notes on the proper installation of a valve cover gasket. I plan on using Permatex Ultra Black RTV silicone in the process. One suggestion I read is, after applying the gasket, silicone and cover to hand tighten the cover, then wait an hour before torquing to specifications. Is this necessary or even a good idea?

  • Welcome to Motor Vehicle Maintenance & Repair! With non-critical parts, such as valve covers, if I use RTV I'll usually tighten them down until the goo starts squishing out, then leave them to cure. Then I'll tighten it down to hand tight. These are parts you don't want to over tighten because they can and will warp. Then you'll almost never get them to seal. Nov 18 '18 at 2:10
  • Proper fastening technique depends on how the valve cover is held down. Some systems just squish the gasket, while others have shouldered bolts that are tightened to the shoulder only, and torqued to very low figures. Without knowing the kind of vehicle and design of the valve cover fastenings, it's impossible to answer. Nov 18 '18 at 3:03
  • David. This valve cover tightens with four large nuts around spark plug tubes with a hard gasket under each nut. This squishes the valve cover gasket when tightened. The torque is listed at 33 ft-lbs but many people under tighten them.
    – J. Wilson
    Nov 18 '18 at 20:08
  • @J.Wilson 33f ft-lbs sounds really an overkill for me, for a valve cover! I would: a) apply RTV silicone to the gasket, spread with the fingers to a light, thin, even layer...like painting it b) wait a few minutes until the RTV hardens a bit before handing, positioning and securing the gasket and then c) hand tighten the cover in X pattern from center to outside, two or three passes, so the gasket gets flat evenly. I never "draw" a thick bead of RTV ever, useless and it can penetrate into the assembly. Jan 3 at 3:25

The idea of just hand tightening is to make silicone more like rubber. When you tighten it without waiting for silicone to rubberise it with squeeze the silicone in and out. But when you wait silicone gets like rubber and then you can tighten the gasket bolts to create better seal. Make sure to tighten the bolts to proper spec and not over or under tighten them.

  • So, AsenM, you do think this is a good idea to wait an hour and then torque the valve cover?
    – J. Wilson
    Nov 18 '18 at 20:11
  • Yes that will be good.
    – AsenM
    Nov 18 '18 at 20:14
  • Thanks, it makes sense to me. This engine is notorious for oil leaks.
    – J. Wilson
    Nov 19 '18 at 6:03
  • Hand tightening also help spread the gasket bead to a uniform thickness.
    – user16128
    Dec 13 '19 at 13:17

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