Not sure which vehicle you are referring to. Most modern cars are not fitted with a radiator drain plug. To drain the system, you usually have to loosen or remove the bottom hose.
No.
if its a 300 tdi it will be in a round pot at the front of the engine next to the radiator
You have to take off the belly pan and it is in the big silver pan!
Define 1997 Jetta: GL, GT, TDI, GLS or GLX model?
Take the skid plate of the bottom of the engine compartment. The oil drain plug is located on the back center of the oil pain. It's a 19mm bolt.
tdi200 gearbox[ie LT77] is better than tdi300
A TDI doesn't have spark plugs. It has glow plugs.
To change the oil on a 2006 Saab 93 1.9 TDI, start by raising the vehicle and securing it on jack stands. Remove the oil drain plug and allow the old oil to fully drain into a container. Replace the drain plug, then remove the old oil filter using an oil filter wrench and install a new one, applying a bit of new oil to the gasket. Finally, refill the engine with the appropriate type and amount of new oil through the oil filler cap.
Sealed unit- you can't. However there is a drain plug/level indicator toward the rear of the gearbox. Here is a good description. http://forums.tdiclub.com/showthread.php?p=288052
http://www.fishh2o.com/Misc/Misc/Passat%20Radiator.html
rtrt
In a 2005 VW Passat TDI, the engine block heater plug is typically located near the front of the engine, often on the passenger side. It may be found near the oil pan or under the hood, close to the radiator or grille area. Look for a cord with a three-prong plug that is usually secured with a clip or strap. If you're having trouble locating it, consulting the owner's manual can provide specific guidance.