oil return hose

[87quest']

ok so im not postive if its the oil return but its the hose on the passenger side of the car. iv had someone explain it to me but is it possible that i could get a piture

[mikec]

The oil return from the turbo comes out the bottom/center of the turbo - in the center of the cast iron "cartridge" portion between the two snail-shaped wheel housings. Look for a metal tube bent at a shallow angle... this tube bolts to the bottom of the turbo and goes into a braid covered rubber hose about an inch in outer diameter. This hose extends forward a few inches and then turns to plug into a port on the side of the engine: look for a fat port just above the water pump hoses in the silver cover at the front of the engine, just below the valve cover.

 

I'm guessing though you are questioning the funny looking "oil return" pipe sticking up from the oil pan itself on the exhaust side of the engine? If so, that has nothing to do with the turbo's oil. It's part of the "oil separator system." Indiana has posted diagrams from the factory manuals many times on this system. Basically it is 3 hoses and one tank:

* A metal cylinder/tank screwed to the side of your air filter box; it's about 3 inches in diameter. Many folks remove this thinking "it's an emissions part I don't need, I'll clean up the engine compartment by removing it." Very bad/stupid thing to do. Anyway, it should have 3 pipe ports on it: one on top, one on the side, and one on the bottom. This tank is the oil separator tank.

 

1: The oil separator side/center port connects to a half-inch or so diameter hose, about a foot long, that in turn connects to the metal pipe running along the top of the valve cover; this pipe is screwed to the valve cover and the turbo. The other end of this pipe connects to a rubber 90 degree elbow hose which plugs into the port at the very back corner of the valve cover. If your car has a stupid breather filter there... get rid of it. Somebody tried to "clean up" the engine bay improperly.

 

2: The top port of the oil separator goes to the hole on the front of the heavy-duty ribbed "accordion hose" that connects the air filter canister to the turbo. There should be a metal pipe sticking out of the accordion hose.

 

3: The bottom port of the oil separator runs to that pipe sticking out at an angle from the side of the oil pan.

 

Look on www.starquestgarage.com for the various manuals and files you can download - factory service manuals and parts lists/diagrams. On the parts list diagram, engine file, look at page 21 of 36 for this diagram. The next page has the part numbers for the various bits. You'll notice a clip (part #8 in the picture); this is a white plastic piece attached to the car chassis/frame rail in the engine compartment below the air filter canister and the oil pan pipe... it's supposed to keep the rubber hose from flopping around too much. The diagram doesn't show the metal pipe running along the top of the valve cover (that I described in #1 above); it shows what looks to be a long rubber hose. That'll work fine - as long as you route it so the turbo doesn't melt it.

 

mike c.

[87quest']

so what if you dont have the stock air box but the hoses are still there?

[Indiana]

What year car? The oil separator hooks up the same way, the reason for that hose there is to provide the low pressure source for the crankcase as it filters through the separator.

 

There is a bypass hose from the MAF on the 88/89 cars.

 

There is a port for the charcoal canister to vent fumes from the fuel tank.

 

There is a water drain hose off the underside of the can to the frame rail, its there and not open so that bugs don't crawl up in and next in the filter but they can if they enter through the fender apron but its supposed to be dry in there.

[mikec]

Factory air filter canister or not, you need the oil separator tank that normally is bolted to the side of it. Attach that tank somewhere in that general area, with the top of the tank about even with the top of the radiator so it can do it's job. If you have aftermarket "hard pipes" or elbows or whatever in place of the factory accordion hose you'll need add an approximately quarter inch diameter port to connect to the oil separator's upper port.

 

The oil separator system basically takes over for the Positive Crankcase Ventilation (PCV) system during boosted driving. The PCV normally uses intake manifold vacuum to "suck out" the engine's crankcase of blow-by gas fumes which would otherwise a) gas fumes collect and can be an explosion risk, are corrosive to some of the engine's guts, and c) would build up pressure blowing out gaskets & seals. Folks that try using old-style "breathers" on the valve cover end up finding pressurized air shoving oil mist through the breather.

 

During on-boost driving, there is no intake manifold vacuum so the PCV system can't function. But there IS vacuum in the ribbed accordion hose thanks to the turbo sucking so hard... so the oil separator system "channels" this vacuum to the valve cover to suck out the crankcase pressure. The oil separator tank itself traps/catches any oil mist picked up through the valve cover and instead drains that oil back to the oil pan... instead of having that oil mist whack the turbo compressor wheel and then be ingested by the intake manifold... so you don't "burn oil" on boost.

 

mike c.

[87quest']

thanks mike your pretty smart at this stuff and yea the kid that had it before me prolly through away that tank so i know where a few parts cars are around here so ill to take a look to see if they still have them and the car is and 87 Edited April 13, 2010 by 87quest'