There is no o ring or copper washer used on the 90 fitting up top. As you can read below you can use some loctite thread sealer if needed on the fittings threads going into the turbo. The fitting going to the line is an taper seal needs nothing. If you over tighten they will leak from cracking the line seal inside. You can get bad lines also so Bd would replace this I had it happen before. You need to contact the person that sold you your kit to help you.
Install the JIC – NPT 1462321 oil inlet fitting into the turbo oil supply port facing in the same direction as the compressor outlet. DO NOT USE TEFLON TAPE OR PIPE DOPE FOR SEALING PIPE THREAD. IF SEALANT IS REQUIRED, USE LOCTITE 592 p/n 59241
Thread the upper oil line 1462325 into the exit/output of the check valve 1462327. Thread the lower oil line 1462324 into the entry/input of the oil line. Both these threads are pipe threads, so do not use Teflon tape. A very small amount of liquid pipe dope may be used. With the line assembled, oil should be able to flow to the turbocharger but should not be able to drain back. With the vehicl e on the hoist, locate the oil filter/cooler assembly. Just to the right of the assembly on the block you will be able to see a 19mm bolt that leads to the engine oil rail. You will need to remove this bolt. Once the bolt is removed, clean the taper area and thread in the M14x1.5 adapter 1462323. Be sure to remove the outer washer that holds the O-ring in place . lubricate the tightening. O-ring Also, before tightening.