About to replace my condenser this weekend on my 2018 Sierra SLT.
Same issue in the same location. Mine even has the silver bandaid from the factory.
To add insult to injury I found out my truck has the new 1234yf refrigerant.
Thus I had to get new adapters for the fittings and can tap for my manifold gauges.
According to what I have seen, it takes 16oz of the 1234yf and 6.2oz of PAG-46 for a complete replacement. Not sure how much oil to add for the condensor replacement since most of it should be still in the system.