2004 Tino smoking??

[dcd1979]

Hi my father has a 2004, 2.2 diesel Tino, about 2 years ago it developed a problem with heavy grey/blue smoking he had it diagnosed as a turbo fault so sent it to a garage to have a new turbo fitted and all was well until a few months ago when it started smoking again, this time I took the pipes off the turbo and they where full of oil so suspected turbo again, as the new 1 was just out of warranty decided to buy a good second hand turbo and fit and was great until we started it and it was no different so spoke to the seller and he supplied another turbo free of charge fitted that and all was good for about a week then started smoking again, is there anything else to look at that could be causing the problem? Also when removing the oil return pipe from turbo to engine it was dry is this right?

Thanks in advance for any help given