How to Replace a Valve Cover Gasket

[whitefish]

I found this video really helpful when I did mine.

https://youtu.be/lTY17bq6LkM

I replaced the valve cover gasket about 20,000 miles ago and it instantly didn't work. At first it was a slow leak that progressed to leak everywhere (especially the spark plug holes). I just replaced the gasket again and no leaks anyhere. I think the following made the difference:

- REALLY clean the mating surfaces. I used brake cleaner and light sanding with 220 grit aluminum oxide paper to get the metal nice and shiny. I cleaned the valve cover well and let it dry. I followed this by scrubbing the gasket recesses well with rubbing alcohol.

- I used an RTV sealer (Permatex Ultra Black) on all the surfaces. I know one isn't supposed to do this, but I was making damn sure this thing wasn't going to leak. I used a very small bead on most of the surfaces, but a heavier bead on the spark plug holes and in the cam corners. The RTV oozed out slightly in the areas with a heavier application and not at all everywhere else. I had a look inside with my inspection camera and there was no RTV where it shouldn't be.

- I tightened the valve cover bolts using the technique described in the above video (I couldn't find any reference to a GM tightening sequence in my shop manual). Final torque was 89 in/lbs.

While I was doing this repair, I cleaned all the oil and debris out of the spark plug holes and replaced those as well.

I'll report back after a few hundred miles on whether this worked and its still leak free.