If the current DV is leaking boost would I get a warning on the dash? Had my GTi 6 months now I was just wondering whether I should replace the DV or not as everyone seems to. Will I notice a difference even if the one that’s fitted is ok? It’s a 2006 model and I’ve no idea if it’s been replaced before
Probably not, unless it was losing so much boost it triggered a code. A DV can deteriorate over time, losing more boost as time goes on. So not only do you rarely get a fault code, it can be difficult to gauge a slow drop in boost over time from actually driving the car.
It's deemed good practice to replace the DV at service time, or perhaps every two services. At the very least it's a good idea to do a visual check of the valve from time to time (although not all DV faults can be immediately spotted by eye). Same goes for checking the cam follower too. That one is crucial.
When I test drove my GTI up I knew it was a bit down on power. Everything else about the car was perfect - big history, annual VW services etc. So I took the punt on it just needing a new DV. Few weeks later a new revision G went in, out came the old and obviously split revision C, and it felt like it'd had a mini remap! Boost restored.
Not everybody will gain that sort of power bump - there's a fair chance your DV is working fine. But it's a very good idea to get it swapped out anyway for peace of mind that you're getting full boost for the lifespan of the new DV.
