Hello, I have a 99 Forester that has a small oil leak. Heres where Im getting confused. The leak seems to be coming from what I believe is called the "water Bypass Hose" The hose that comes out from the oil filter area. There are 2 rubber hoses connected to this pipe on either end which are secured by hose clamps. Im confused becuse as its name is the "water bypass hose" this leads me to believe that coolant should be flowing through the hose (Please correct if Im Wrong). So if coolant is flowing through the line why would I have an oil leak seeming to originate from this line?

 

Thanks

Edited March 19, 201412 yr by bubbalee30003

Oil is leaking from above the oil cooler where it seals to the block.

 

The cooler is a heat exchanger......oil flows through the middle to and from the filter.......and coolant flows through the other passages in the cooler and cools the oil.  There is a small possibility yours has corroded through, and is mixing oil and water.....which could then leak from that hose.........

 

But more likely the oil is coming from the seal above where the cooler mates to the block.  (where the oil filter would mate on engine without coolers)

 

Easily fixed with a few extra minutes work next oil change.

 

What you need is a 15/16 deep well socket, and the large orange O-ring from subaru for sealing the cooler.  Dealers ussually stock them.

 

 

So.....remove the filter.......then use the 15/16 socket to remove the tube/bolt in the center that the filter threads too.  Once you do that, the cooler will flop away from the block...You may need to remove a 10mm bolt that supports the coolant line running over to the water pump........clean the mating surface, install the new o-ring and reinstall the cooler to the block.  tighten the tube securely.  Install new filter and change oil.

Thanks so much! however both ends of the hose appear to be leaking even the one furthest from the oil filter. I assume the appearance of the oil leaking from there could be running down the line from the oil cooler gasket. Im sure ill find out once i get into it. I just wanted to find a good place to start. Thanks

Uhm. I would start by checking the coolant and/or oil to see if there's any evidence of cross-contamination. If the oil looks milky avoid starting the engine until everything is corrected or your engine will go belly up.

If the lines are leaking at the hose connections it's time for new hoses. Water coolant line rubber isn't oil resistant and breaks down when coated with oil. The resulting mess looks cross contaminated. 

the correct name is oil cooler pipe, The bypass pipe goes from water pump  and tees into the IACV and heater input.

see

Edited March 20, 201412 yr by ocei77