It is most unfortunate that VW (the manufacturer of your engine) didn't build these engines as stoutly as we all would have liked. They built them to a certain price point and they were used in light delivery trucks and some were obviously sold to Volvo. You may be at just the tip of the iceberg here as far as the maintenance needs of your engine (seals, gaskets, hoses, etc., etc.) and sound like you are at a very steep part of your learning curve wrench-bending wise as well. If your go for it approach doesn't get you where you want to go, and you like Volvos as cars, there are a bunch of gas powered ones out there that get reasonably good mileage, you can find parts for, and may suit your current mechanical expertise better. Just steer clear of any gas V-6 cars, as they share similar traits with the Diesel as far as being mostly a red-headed stepchild for parts and maintenance support.