AudiForums.com - A4 B5 Turbo Replacement DIY without removing front end!

This is a relatively easy job, but it is time consuming. The first time i did this is it took about 5-6 hours. I suggest you drain your oil (required) and coolant (recommended) before starting as it will save alot of mess. Jack the car up enough to get under freely and set up jack stands. Make sure you buy all the gaskets necessary (Manifold to turbo, turbo to cat, oil return line to oil pan, return line to turbo). Feel free to ask any questions!

List of tools/parts:
Manifold to Turbo Gasket
Turbo to Cat Gasket
Oil Return line to oil pan gasket
Oil return line to turbo gasket
17mm wrench
17mm socket
10mm socket
Ratchet (with extensions and swivel)
6mm Allen key/socket
8mm Allen Key/socket
15mm wrench/socket (two of these)
Screwdrivers of various sizes
Adjustable Wrench

1. Remove your air box and unscrew this check valve:
Attachment 25103

2. Remove the corner light by first pressing down on this tab and pulling the corner light out (this is option but it makes everything much easier, skip if you have one-piece headlights):
Attachment 25104

Then remove the three bolts holding the headlight in place, two on the top, one on the side:
Attachment 25105
Attachment 25106

3. Disconnect the n75 sensor by clipping the zip tie circled and taking out the metal clip holding it in place:
Attachment 25107

4. Disconnect PCV valve by removing the hose clamps at both ends:
Attachment 25108

5. Disconnect the two lines connected by hose clamps to the n75 valve (one is already removed in this picture):
Attachment 25109

6. Disconnect the diverter valve hose:
Attachment 25110

7. Unscrew the turbo inlet pipe and pull it out of the way:
Attachment 25111

8. Unbutton the coolant feed line heatshield:
Attachment 25112

9. Using a 17mm wrench, unscrew the oil feed line (have a pan under the car ready to catch any fluids):
Attachment 25113

10. Using an adjustable wrench, unscrew the coolant feed line:
Attachment 25114

11. Using a 17mm wrench, remove the three bolts holding the hot side to the catalytic converter. The one closest to the engine, slowly work it off with the 12 point end. The bottom one (not pictured) is a royal PITA, using a ton of extensions, a 17mm socket, and a swivel to work it off:
Attachment 25115

12. Get under the car and locate the flex pipe on your exhaust, right next to it should be this:
Attachment 25116
Hold one side with a 15mm wrench and using a 15mm socket/wrench to remove the nut, the exhaust will be free now.

13. Remove these two 10mm bolts holding the oil return line to the oil pan:
Attachment 25117

14. Remove these 3 bolts holding the turbo to the exhaust manifold, spray them down heavy with some pbblaster or brake kleen to break down some of the crap holding them on. Use a 17mm wrench and remove them.
Attachment 25118

15. Remove this bolt with either a 6mm allen key or socket, be careful as the turbo will be free when you do.
Attachment 25119
Attachment 25120
Then on the other side of the support bar, loosen the 8mm allen bolt:
Attachment 25121

16. Move the turbo towards the passenger side of the car and remove the hose clamp on the coolant return line and pull it off the block:
Attachment 25122

17. Now the fun part (NOT!), get under the car and with your right hand grab the turbo and with the left grab the oil return line. Slowly move the oil return line up and out, it will take some time and is much easier with one person above the car and one below trying the maneuver it around everything. This is where the loosened turbo support bar helps, you can move it around so it is one less thing you need to go past. I don't have pictures as it is a very hands on job. Good luck

And that's it, you should have the turbo and the turbo oil return line removed, simply remove the two 6mm bolts holding the return line to the oil turbo and reconnect to the new one if you are not replacing it.