Re: Valve cover leak...
I was reading some time back on this forum that some people were using stainless steel screws in place of the OEM aluminum screws. I warned that this may not be too smart due to galvanic corrosion and there was a reason why the factory used the special and more expensive screws.
I later found the chart that listed the various metals in order of there susceptibility to corrosion due to this phenomenon.
The stainless steel screws should not be used in magnesium and magnesium alloys. In severe conditions they should not be used in aluminum alloys either.
See the chart here.
You can see that under certain conditions the differential value of the materials anodic index (V) should not exceed a certain value. Engine blocks are not cheap and if you lived in some climates your engine could start to lose weight. 
You need an electrolyte and damp salty air counts.
Last edited by onehundred80; Feb 28, 2012 at 08:43 PM.