no. A very thin layer of thermal grease is GOOD.
The gunk is just mean to fill the microscopic gaps, not act as an inch thick buffer.
And if you installed the heatsink correctly you should have zero problems.
<b><font color=purple>[Rik_]</font color=purple> I wonder how many people have made their own phasechange system?
<font color=blue>[LHGPooBaa]</font color=blue> I get phasechange whenever i eat a hot chillie