Leaking copper drain gasket

[y_p_w]

Had a slow drip leaving oil on the garage floor. On my last change I
decided to use a copper gasket that was the right size although I had
some hollow steel Subaru washers. I'd bought it years ago for use in
a Honda manual transmission fill bolt (same 18 mm internal as Subaru
bolts).

After removing the underspoiler, it was pretty obvious it was leaking
from the plug/gasket. So with a quick motion, I removed the plug and
covered up the hole with my gloved thumb. Then with my free hand I
removed the copper washer and placed the new steel one on and returned
it and tightened it. I couldn't have lost more than 3 oz of oil -
probably less. It was Mobil 1 5W-30, and I didn't particularly want
to pour the drained oil back, in case there were large metal shavings
in the pan.

I looked at the copper washer, and the crush marks were all around the
circumference except maybe for a 5 mm section that didn't seal (no
mark). I was rather surprised, as I had really cranked it tight.
Anyone ever have a washer not seal even when cranked nice and tight?

 

[Rick Courtright]

I looked at the copper washer, and the crush marks were all around the
circumference except maybe for a 5 mm section that didn't seal (no
mark). I was rather surprised, as I had really cranked it tight.
Anyone ever have a washer not seal even when cranked nice and tight?

Hi,

Seems odd to me--I've used copper gaskets on a variety of cars,
including my Subie, and never (knock on wood) had one fail to seal. In
fact, back in the days of air cooled VWs, we used to re-use them until
they were nearly paper thin and they'd still seal!

Next time you do an oil change, I wonder if a careful inspection would
reveal an ever so slightly damaged section of either the pan or the bolt
causing your woes?

Rick

 

[y_p_w]

y_p_w wrote:




Hi,

Seems odd to me--I've used copper gaskets on a variety of cars,
including my Subie, and never (knock on wood) had one fail to seal. In
fact, back in the days of air cooled VWs, we used to re-use them until
they were nearly paper thin and they'd still seal!

Next time you do an oil change, I wonder if a careful inspection would
reveal an ever so slightly damaged section of either the pan or the bolt
causing your woes?

Definitely wasn't the bolt. Leak came from the side against
the pan.

I thought it was strange. It should have sealed properly.
I really cranked it tight too. Here's a picture. You can
see where it crushed and where it didn't (at the top).

<http://img58.imageshack.us/img58/3617/washerap6.jpg>

 

[Mike Copeland]

Definitely wasn't the bolt. Leak came from the side against
the pan.

I thought it was strange. It should have sealed properly.
I really cranked it tight too. Here's a picture. You can
see where it crushed and where it didn't (at the top).

<http://img58.imageshack.us/img58/3617/washerap6.jpg>

Could you have cross threaded it?

 

[AS]

It does looked as if it had been damaged on installation. Are u using
the subaru seals? The originals are not copper, are they?

Good luck!