We get this question a lot: "Should I change just the head gaskets on my Vanagon?"
Changing only the head gaskets is usually impractical on a high-mileage/older water-boxer for many reasons:
1. Oftentimes, the cylinder heads are too corroded, and spending time and money on them may not be logical (especially if they are the original German heads).
2. Even if the cylinder heads are not too corroded, they may be cracked—and that could, in fact, be where the fluid is leaking. Please read our article regarding cylinder heads here.
3. The cylinder is often stuck to the cylinder head, making it impossible to remove the cylinder head without at least one cylinder coming along with it.
4. Even assuming that no cylinder is stuck (unlikely)—all the cylinders are going to be disturbed, since it is the cylinder head that holds them in place. When the cylinders are disturbed, you'll need to deal with the area between the cylinder and the engine block at the bottom. If the cylinder is stuck to the cylinder head and debris gets in the lower contact area, you'll be required to remove all of the cylinders.
5. Close examination of the cylinder head studs (4 long, 2 medium, and 2 short per side) often reveals one or more corroded stud. It is almost impossible to replace one of these studs without completely disassembling the engine.
The bottom line is this: If you are paying a professional to do the work, it may quickly become very non-cost effective to pay them to do just the head gaskets. Be prepared to pay at least 4 hours for your shop to get to the point of knowing one way or another. The chances are about 50/50 that it can be done at all. Therefore, you should also be prepared to bite the bullet and simply replace the entire engine long block with a fresh GoWesty unit.