Strange noises after driving more than 30 km
 

Well, hello everyone. I'm a bit at a loss because my mechanic just can't find the problem and we have a long trip to Germany coming up. I'm in Switzerland myself.

Anyway, the problem is this: When we drive short distances, everything seems to be fine, although it's possible that the issue exists but just isn't audible. As soon as we drive longer distances, I'd guess 30km and more, especially when we drive beyond 80 km/h, we get this strange noise that sounds as if the transmission was running on higher RPMs than it actually is. Or as if some fan was running in overdrive or something. This is mostly audible as soon as we leave the highways and speeds come down to 50 to 80 km/h.

The strange thing is, this seems to have an effect on the steering as well, because as soon as more turning is involved (in villages and cities), the steering will produce creaking sounds as if from a bad spring when turning 90° corners or more. It doesn't happen, at least as much, just by driving curves.

Since everything goes back to normal after driving around 50 for 10 to 15 minutes, I assume it could be an overheating problem of some kind. Perhaps something generates too much friction? But what could that thing be? The tension pulley on the engine has been changed, and some of the noise has gone away but not all of it. I believe the water pump has been changed as well.

Does anyone have an idea what to look for here? Any advice is highly appreciated.

Regards,

Marco

Perhaps I should add that it's a 2002 Voyager 3.8l AWD. :)

Seriously? Nobody ANY idea?