I bought a used 99.5 jetta here in balmy Toronto, Canada last month, and i've had a rather interesting problem with it. So far i've been very pleased with its highway performance, driving it smoothly at
130-140 km/h (75-85?). Today, however, i was driving at around that speed for about 20 minutes on the highway with 3 other people in the car, and suddenly i heard the car making this very loud almost farting-like noise. At first i thought it was the plastic stone-deflector thing vibrating from a strong crosswind or something, as it was intermittent (not a constant noise) but about a minute later, i could feel a sudden loss of power to the engine -- i was now flooring the car and barely maintaining 120km/h!So i get off the highway... and the engine sounds a bit different. I rev up to 2000rpm -- NO turbo whistle, and the engine is extremely weak. I then turn the car off, wait about 10 seconds, restart it, and there goes the turbo again, as if nothing had ever happened.
a little bit later, i went on the highway for a boot up to about 145 and again that kind of plastic farting noise... i take the car out of gear, and the reduction in rpm down to idle seems to have _no_ effect on that sound. I even was trying to floor the car in 4th gear near redline for a while, but did not succeed in getting the turbo to stop working as it had done before, nor can i get that weird sound to happen with anything else other than high speed...
so my question is... do i just have a coincidental problem -- the plastic vibrating and the turbo overheating (?) or is that loud noise coming from the turbo?
can anyone shed some light? thanks