Simple oil change question - 156 2.0 TS (2000)

[MattK]

Hi all,
It's hard to believe but I have never done a full oil change on a car. I bought some Nulon full synthetic 10W-40 from Repco and a filter for my 156 2.0 TS. I'm expecting it will be a matter of removing the undertray, removing the fill cap, undoing the sump plug, draining into a pan, removing the oil filter, dribbling a bit of the new stuff through to wash out the old, then replacing filter and plug and filling normally.
Where I am a bit stuck is that I expect I will need to replace the copper washer on the sump plug but I can't figure out what to buy. Seeing them online in the UK, they're like 50p for a M18 x 24mm x 1.5mm (but postage is nuts). But putting my model number into the Repco site shows up a 22mm washer as "suitable". And the Supercheap Auto site seems to want either $40 for a copper sump washer which is ludicrous (I am probably looking at the wrong thing) or there are multipacks which may or may not include that size.
On the other hand on eBay I can buy what looks like the correct size along with a magnetic sump plug from the UK for $15 ish, thought that may be worth it.
Any advice?
Also - before I do something dumb - I've heard that sump plugs can be a little tough to remove. I wondered if putting a hex bit in an impact driver would offer a better shot of unsticking the thread, or is that likely to do something helpful like crack the sump?
Thanks for your patience with my newb questions.

[johnl]

Do you have a blow torch, or even a gas stove or a gas BBQ? The old copper washer can be annealed to make it 'fully soft' again. The old washer will have been partially work hardened due to being slightly crushed when the sump plug was originally tightened (copper is very soft in an annealed state). Annealing will allow the washer to readily 're-crush' and seal as it should, good as a new one.

To anneal the washer just heat it until the entire washer becomes red hot (don't worry too much about melting it, you'd have to get it very hot indeed for that to happen). It can then be 'quenched' in water while still hot, or just allowed to slowly cool. 'Quenching' doesn't really make it any softer, but will 'shock' the copper oxide off, making it clean (oxide will form on the surface while the copper is hot, you'll see it, it's black). If you don't quench then the oxide will need to be removed manually, say with Scotchbrite or emery paper.

It's also possible that you could just re-use the washer as it is. As I said it will be partially work hardened from having been crushed a bit by the sump plug, meaning it's most likely still relatively soft (enough), unless it's been re-used like this a few times already. Added insurance would be to use some non hardening sealant on the plug threads and on the washer itself (e.g. 'Aviation Gasket No3', one of my favourites...).

I'd be very wary of using an impact driver. Maybe as a last resort at the risk of rounding off the internal hex in the plug (if the plug is very tight). But before that just see how you go with hand tools and gentle force...

A magnetic plug wouldn't be a bad thing.

Regards,
John.

[MattK]

Very helpful - thanks John!

[bazzbazz]

Just take the sump plug to ANY bolt specialist and they will sell you a handful of copper washers for about $1.

As for the sump plug it will be either a 8mm hex drive or similar large size star torque tip. As long as it hasn't been stripped by some clot previously, a short piece of pipe on the end of your ratchet wrench will be more than enough to undo any sump plug.

[MattK]

Awesome, thanks. Told you I was a complete bunny.

[bazzbazz]

And I didn't disagree . . . . . 

[johnl]

a short piece of pipe on the end of your ratchet wrench will be more than enough to undo any sump plug.

I've encountered a few sump plugs that were ridiculously tight, tight enough to require using a breaker bar. In at least one case it was so tight that the hex head rounded off when attempting to undo it. From memory this was either a Kent or Pinto engine in a Ford Escort, which had a rather small hex on the end of the plug...

Regards,
John.

[Citroënbender]

I also recommend acquiring the filter end "socket" to suit, it saves much grief when removing.