There is only 1 large O-Ring for the cooler. You need to remove the oil filter first, and then using a Deep Socket to remove the NUT that is holding the cooler to the block. There is no need to disconnect the coolant lines that are attached to the cooler. Note those are COOLANT lines. Took me less than 1 hour when I last did the work.

Here are some youtube videos:

(For the outback, it is sideways mounted vs vertical for the Forester).

 

Oh Thank you Jesus! I have a slow leak starting at 190K with a non-turbo engine. I saw some videos out there with multiple seals and and requires lots more work. I thought this seemed different from my engine. Thanks for the video links.
I just did this on my Mazda Miata and it was fairly painless and made everything dry again.

 

Thank you.

I've actually watched both of those. There are a couple of others that mention "all 4 seals"...those videos are all for turbo models, just wanted to confirm I only have one.

For example, this one:

 

So the O-Ring that is the main culprit is just that 1 O-Ring(The Orange One). He is talking specifically about other O-Rings that are not known to leak, and also maybe specific to his TURBO vs your NON-TURBO engine. Pretty much most owners on here that have fixed this issue have only replaced just the Orange One and nothing else.

Look here, this might help:

1998-2005 Subaru Forester Oil Cooler 21311AA010 | Subaru Parts Store

1998-2005 Subaru Forester part # 21311AA010 - Oil Cooler

www.subaruparts.com

Parts diagram of the oil cooler. Makes no mention of "those" other O Rings.

 

Ok got it now. Many thanks

 

I replaced mine two years ago. Just look at the difference between old (left) and new (right) upon inspection. Shocking.

 

Quick followup question:

I'm only about 1000 miles into the current oil change. Is it possible to change this seal without draining all the oil from the oil pan? I will obviouly lose some when I remove the filter but I thought I might be able to get away with only draining a quart or so...I think the filter is higher than the pan.

 

@SmokeyBee Yes you can do the gasket change without an oil change, just add back in the missing Quart/Liter when you're done. The other choice is to leave it alone until your next oil change.

Remember the oil cooler is screwed into the block and not the drain pan and therefore sits higher than the pan. So you only lose what's in the oil filter.

 

That's what I was hoping for, thanks

 

Others are correct, order up that one orange seal and the leak will be gone!

I had the same observation comparing the old/new seal as SueBrew, and now mine is no longer leaking.

I ordered MAHLE B32074 $3.72 from Rockauto. The Mahle part is made in Japan so it is possible it is an OEM part.

 

I bought one that claims to be OEM from Amazon. No one ever lies on Amazon; what could go wrong?