Wow. Why in the world did they weld the cap to the intake!
For other engines you can remove the cap, see picture in link, clean the dried oil and replace the parts.
This is such an inexpensive maintenance item that if left unchecked can result, as stated, in damage to the front, usually rear main seal that I would recommend changing it at 50K or both if a V8. When I check my E70 the red diaphragm looked fine and I almost put the cap back on. But when I removed it to clean the entire circumference of the red diaphragm was fatigued and cracked.
https://www.ecstuning.com/b-genuine-...t/11127547058/