I don't on my 2006 2.0T. The 0W-40, being a multi viscosity, will become a 40W at higher tempertures. However, I'm no expert, especially when talking about your era 1.8T, so.....I'd check your manual, or look around e-bay to find a manual if you don't have one. In the meantime, using the oil you just put in is probably good insurance as it will definitly be as good or better than what is called for. The only down side is it might be more expensive than something else that might be specified for that engine.