Hairline cracks in valve cover '82 300SD

[lwbdriver]

I have been having some oil leakage (who hasn't?) on my 82 300SD. I decided to take a closer look and it looks like I have several hairline cracks on top of the valve cover between the oil cap and the pcv valve (is that what that is?) They are very slight, but you can catch a fingernail on them. Has anyone else seen anything like this? Very odd, in my opinion.

I spread some JB Weld around like peanut butter and it seems to have helped somewhat, but still some leakage under the oil cap, as well. I guess a new one is in the future.

Just wondering if this is a common ailment? My car has 124000 on it and runs like a proverbial top. I have had it for about 6 months now and couldn't be happier.