I believe that it is 9 litres. Don't put just any coolant in it, use G12 plus. And definitely DO NOT mix regular coolants with G12, it could make you very unhappy.
2000 Jetta VR6 has a timing chain, NOT a timing belt
it has 2
VR6 12v-175hp around 170lbs of torque VR6 24v-200hp around 180lbs of torque
Capacity is 5.3qts., and calls for a 5w-30.
6 qts 6 qts
No different exhaust lengths and bends that's like saying can a limo exhaust fit on a pinto
Under the coolant bin, on the right top side of the hood.
90 bucks for part
You can buy a Jetta VR6 for example on eBay or carsforsale. Or search a carshop near by you and asked for a Jetta VR6. I am sure you will find you dream car.
VR6 drive belt pathway
pretty sure that they are 12 valve
Your battery is bad, your alternator is bad or you have a wiring problem.