Hello, My name is jim and I've joined this forum for help fixing my 2000 jetta tdi 5spd black. I bought the car in september for 4800, and it drove well for about 3500 miles. One day I took off if the morning, I got about 1 mile down the road and the coolant light comes on, the engine was still relatively cold, but the coolant system had quite a bit of pressure built up. The coolant was discolored and definitaly contaminated and of course if was low. I topped off the coolant and kept driving the car. Every 400-500 miles if would lose about a cup of coolant, this is how much I put in when the light came on. This went on for another 2000 miles. I did the sniff test on it, and it did change color but only if the engine was revved up over 3000 rpm. The car has a vnt-17 and a mild evry mod (witch was turned off when coolant issue started), So i figured the higher boost (19 psi) may have been lifting the head slightly under high boost so I installed arp studs with little luck, altough it did help. So thats why im here I think I can figure it out by searching thanks!