1G Oil return line cause low oil pressure?

[Streetsweeper21]

I just installed a t3/t4 turbo and I have a small leak in the oil drain custom line I made. When I start the car it goes to

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Then at low idle it slowly goes to the L if I don't rev the engine. Before the install it use to go about 1/4 above the mark circled but now doesn't. Would a small leak in oil drain line cause the oil pressure to fall to the L? Because If not I don't want to spend 80 bucks on a oil return line kit for nothing when I can just order a oil pump. Also I have enough oil in the engine.

 

[DSM90AWD]

Would a small leak in oil drain line cause the oil pressure to fall to the L?

No. the turbo oil drain is many x's the size of the feed and should not have any oil pressure in it at all.

Did you check the oil pressure swich on the filter housing as is likely that it is loose/damaged. The "idiot light" is wired separately than the oil gauge so (if working) will let you know if you truely have low oil pressure.

 

[Streetsweeper21]

Okay so I installed a new oil pressure switch for the dash light and changed the oil pressure sender unit this time the gauge stayed a little bit past the mark that's circled above and the pressure mantained normal. I Reved it up a couple times than the pressure went a little low but still pretty much normal. Than when I reved it til 6k than the oil prsesure went sky high pass the H I let the car run a little than turned it off. Would that be the gauge or a bad oil pump? If I get an aftemarket gauge should I get electrically or mechanically? If I let is stay past the H mark what could happen?