Most Volvo Spa (Scalable Product Architecture) models are the same — XC90, S60, V90, V60 — and as most Volvo SPA owners have come to notice, opening the hood gets more difficult as time marches on.
The problem and resolution lay under the hood. Under the yellow release knob (as shown in the photo) is a part called the Hood Safety Catch Bracket (Anchorage; A component to which the Hood Safety Catch or related component is mounted; Part#: 31479077) which holds the release cable in place. This part corrodes over time and / or the plastic simply breaks and the cable disconnects as, seen in the attached video, and as a result, opening the hood becomes a serious problem.
If you notice that the yellow knob under the hood of your Volvo starts to become stiff, or hard to push, or move, then it is time to bring it in to Swedish-Auto and have the problem resolved before accessing the engine compartment becomes impossible and the part breaks off completely. Imagine being stuck and not being able to top-up critical fluids, like oil, coolant, or even just windshield washer fluid so you can see out the front of your Volve!
