Recently acquired 1999 Mk 2 Mondeo 1.8 Petrol and in process of doing first oil change. Apart from the, so far, immovable filter all going well.

I bought a new sump plug washer which is brass, the current one appears to be rubber and recessed into the plug.

Should I pick out and use brass one or re-use the one fitted ?

The copper one is just a universal one, it won't work with your sump plug, it needs a flat surface to mate to.

Keep the o-ring over that copper washer (or ideally buy a replacement).

The rubber O rings are reusable. I did manage to source some new ones for my mk3, as much cheaper than buying a new plug. Inspect it, and if it's not damaged just reuse it. Don't add the copper one as the sump is very thin and might distort around the sump plug hole if you use it. 

Thanks, I will reuse for now but buy new plug for next time.

2 minutes ago, nicam49 said:

The rubber O rings are reusable. I did manage to source some new ones for my mk3, as much cheaper than buying a new plug. Inspect it, and if it's not damaged just reuse it. Don't add the copper one as the sump is very thin and might distort around the sump plug hole if you use it. 

I assume the O ring is specific to the job and standard O's will not do ?

If its like on my mk3, It's a special shape not just an O... this sort of thing :

 

Brilliant, Thanks