What causes a Subaru B4 twinturbo engine develop oil problems in the turbo?

i want to purchase one but my friend's has developed such problems requiring engine overhaul. Is it a common problem. his has done 89000km and is regularly serviced.What causes a Subaru B4 twinturbo engine develop oil problems in the turbo?
Inexpensive turbochargers are not pressure lubricated to the turbocharger bearings by the oil pump. Even when they are a common problem Alignment, suspension . When you turn a hot engine off the turbocharger bearings get no oil pressure or oil circulation. A promlem called ';oil coaking'; takes place. The small amount of oil literaly bakes on the bearings because the hot cast iron side of the turbocharger soaks heat eventually causing failure. If he's determined to keep the car the bearings inside the turbo need to be replaced. His only saviour is switching to a full synthetic motor oil of the recommended viscosity. Synthetic oil has the ability to stand much higher temperature before flashing to fire.What causes a Subaru B4 twinturbo engine develop oil problems in the turbo?
If the turbo ain't any better than that, steer clear of car!
I have a turbo Jetta. A lot of times turbo owners do not use Synthetic oil for their engines. This creates a lot of problems in the long run. Synthetic oil will help keep the turbos a little cooler and is less prone to choke the oil lines, since it is a thinner base oil. Remember that turbo engines breaks down oil much more faster than a regular non turbo car. Also make sure if you do buy the car to have a oil cooler installed to help prolong the life of your turbo.
For future reference synthetics will hold up alot better in a turbo car, the heat resistance is outstanding. Amsoil synthetics: http://www.amsoil.com/redirect.cgi?zo=14鈥?/a>


Also let the car idle a few minutes before turning it off to allow the turbo to cool.