I haven't heard of an oil leak causing a turbo failure, but it can cause issues with some plastic and rubber parts. I defininitely would get the cam tensioner gasket replaced and fix the coolant flange and breather hose issues at the same time. As long as you are using a high quality synthetic oil, your turbo should be fine. Other than that, I'm not quite sure what you are asking. I don't know what Volkswagen's responsibility would be beyond the 4/50 warranty period. If you can't afford to have everything repaired immediately, I would definitely fix the coolant flange to avoid an overheat. If I can help you with anything else specifically, let me know.
- Craig
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