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Discussion Starter #1
Would it be too restrictive & therefore hurt the flow to the turbo to put a cooler in this line? Isn't that the hottest oil in the whole car? It just occurred to me that it might make sense for it to be there. I'm ditching my water based cooler & looking at oil cooler alternatives.
 

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Can't put a cooler there. The oil drain from the turbo needs to be a free-flowing path for the oil to take to get to the pan. Putting any type of restriction in that line will make the oil back up instead of draining out of the turbo.. which will make the oil push past the seals in the turbo cartridge and make a nice smoke show.

Not to mention, the oil drain isn't under pressure, it's just a drain. You have to run oil from a pressurized source through an oil cooler.

The easiest way to set up an external oil cooler on a 6bolt motor is to get a 90 oil filter bracket. It has two 16mm x 1.5 threaded holes on the side that go to an external oil cooler. There's some other threads on the board about that if you search for them.
 

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Discussion Starter #3
The oil TOO the Turbos under some kinda pressure but I cuncur the return from a cooler may need to under some kinda suction - that may be how it's ported at the Oil Filter housing. Of course the oil in the sump is beiing pulled by the pump... I just wish someone else had tried this - I don't want to be the guinea pig.
 

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The oil drain isn't under any kind of suction, it's drained by gravity. That's why turbos are installed with the oil drain on the bottom... gravity is the only thing that lets the oil drain out of the cartridge. If you installed the cartridge with the oil drain on top it would never drain, and you'd get oil pushing past the turbo seals. The oil pump does pull oil from the crankcase, but that doesn't result in any kind of vacuum in the crankcase that would "suck" the oil out of the turbo cartridge. Gravity does it.

Yes the oil feed to the turbo is under pressure, but again, not a good place to put a cooler. Typical oil feed line to the turbo will be 3AN or 4AN size, while a typical oil cooler is anywhere from 6AN to 10AN size. In order to get good oil feed to the turbo, and have large enough lines for your oil cooler, they need to be separate systems.

If you get the 90 oil filter bracket, you can run a 4AN oil feed line to the turbo, and set up an external oil cooler properly as well, since that oil filter housing is made to have an external oil cooler. It has a built-in thermostat and 2 ports on the drivers side to hook your oil cooler up to. Real simple (you know 90 DSMs came with an external oil cooler from the factory, right?)...
 

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Discussion Starter #5
Got it - I'm on the hunt for a 90 housing - I picked up on the Oil Cooler differences when I went thru my Oil Filter blew off crisis.
 
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