Iknownothing

Coolant level Is fine . Oil looks fine (as in not contaminated)

still Waiting to get it in garage . Hopefully should be today . Really hoping it’s not the head gasket 

Hi. New to site and very limited/ zero knowledge of this issue . 
 

Owned the car (2007 a6 2.0tdi auto) for around a year . Had zero issues apart from oil min warning light twice and topped up within a day or so ....

however. Last week it came on again on way to work. I topped up 2 days later . Went to work next day no problem.

on way home around 1.5 miles from home the red “low oil pressure “ warning came on .

So close to home and the car went into limp mode the (I’m assuming) turbo made an awful whining noise . As it struggled the last 100yards the break peddle went stiff and really struggled to come to a stop outside my house . 
 

got the car recovered to a mate of a mates garage who checked it and changed the hex key balance shaft . He said once the oil pump was going again all seemed well.

drove around 5 miles and the white smoke the car is belching out looks horrendous. Also got a massive drop in power . 

would this be a blown turbo as suspected? Like I say I have little knowledge but I definitely know it made a horrible sound . And now white smoke ? 
 

sorry if I’ve missed anything but would love to pick your brains .