Originally Posted by OMMB

Hello,

My stock om603 turbo is leaking from the oil feed line where it meets the block. The flare is messed up, and sadly there is not enough material left to cut and reflare.

Getting a replacement steel line turns out to be not as easy. Most used ones are trashed or just too expensive.

I saw that -4 AN lines with adapters to block and turbo are readily available. I am favouring this approach, but I have a few concerns that I hope someone here can shed light on.

I am mostly concerned with oil flow. The original line is quite big in diameter, an -4 would lower that. Is there a restrictor in the line or in the oe t3 garret?
If so what size restrictor. If no restrictor is used, will a -4 line starve the turbo?

If someone has information on this or has done this I am grateful for any information.

Thank You