Ok here's where I look stupid but I just want to check.
Just changed my oil and a new fram filter which came with a large green o ring in the box.
Now nowhere is there a o ring like this that I can see on the old filter or filter cover?????
The only place I can possibly see it fitting is over the threads on the filter cover so it seals under the head is that correct??
And if so how the hell was it not leaking without one on before??