There are two coolant lines running to the throttle body. One of them comes from the coolant rail on the back of the heads, located behind the Bank 2 head (Driver Side). As for size, I’m fairly certain it’s 1/4”. The other hose to the throttle body extends down under the intake boot, running along the heater core pipe along the side of the engine above the exhaust manifold. There are two sections to the PCV System. The valve itself is located on the intake side of the Bank 1 valve covers, on the back of the valve cover. It is a small plastic piece that is inserted into a rubber grommet, on the 2001 VQ. The valve itself is rather fragile, and if the hose back there has dry-rotted, you’ll have some difficulty removing it. This valve feeds the crankcase gases into a tube under the lower intake manifold, and exits into the intake near the butterfly valves above cylinder 4. The secondary part of the PCV is an extension of the chambers within the valve covers. The valve covers on the 2001 VQ are large and typically made of aluminum, having chambers at the top for the gases to collect. On the Bank 1 side, there is a large outlet (about 1/2”) that utilizes a hose along the top of the timing cover to reach the other valve cover. The inlet on that side is roughly the same position as the Bank 1 side, but mirrored. There is then a large outlet on the back of the Bank 2 valve cover, on the exhaust side, which feeds directly into the intake boot, before the throttle body. It is a rather efficient PCV system, and I don’t recommend tampering with it. The VQ is quite sensitive to crankcase pressure, and will often react with oil seepage, misfires, or moisture buildup in the oil. It’s cumbersome, but it works. Above is a picture of my engine stripped down to the heads. I highlighted the PCV path along the valve covers with yellow.