For anyone reading this having the same issue, it was solved by replacing the oil filter housing.

Here is a good youtube video on the steps to replace the part.

I'm going to purchase the oil filter housing. Would it be a good idea to replace the 'PCV hose' as well? (links below).

https://www.fcpeuro.com/products/volvo- ... g-31338685
https://www.fcpeuro.com/products/volvo- ... vo-8670008

This seems to be the issue! When i take the oil cap off, the sound stops and you can feel a large amount of air being sucked in where i took the cap off. Is the actual part that needs to be replaced the "oil filter housing" or could it be a different part of the PCV system that is clogged ...

I recently popped a few codes on my '2012 Volvo S60 T5' and there is a strange hissing sound coming from the car. I recorded the sound and uploaded it to youtube (link below). The sound only start after the car is warm (about 30+ min of driving) and is only present at idle or very low RPM. Once i ac...