VALVER COVER GASKET LEAKS OIL 91 300SE

[steve3656]

I changed my valve cover gasket 3 times, by 2 different mechanic and it still leaks oil, I am planning to change it again myself this time, can anyone with a similar problem offer any suggestion. Someone suggested that maybe the Valve cover itself is bent and not level, so I purchased a used one and will replace the original one. I was thinking of using a sealant like VICTOR REINZ Sealing Compound or YAMABOND LIQUID GASKET MAKER but my mechanic advise against using sealants, any suggestion would be appreciated