Sump drain plug washer

I seem to be asking a lot of questions; och well maybe some day I will be able to give advice to others.
Going to change my engine oil and prefer to use a new soft copper washer with the drain plug but I do not know the correct size. Does anyone know? (Our nearest Suzuki dealer is quite far away).
As I have this daft thing about using only the best engine oil I hoped to use the preferred 5-30 and wanted a fully synthetic such as Castrol Edge. However all the containers say suitable for Ford, or Vauxhall etc. Hopefully that just means these makers have approved those oils but other makes can also use them.

Chilgrove.
(BTW how should I sign, my name or my nom de plume or does it not matter)

The drain plug gasket on my Jimny was plastic or nylon and I, like you, prefer a squashy copper seal. I had a VW Beetle copper asbestos on the shelf and it was perfect. you can get them from VW Heritage / Karman Konnection or a VW agent cheap and good.

I'm not sure if it is a good idea to switch to fully synthetic. I could be wrong and I'm sure wiser heads than mine will have the answer, so here goes. I seem to remember that it is OK to go one way and not the other with oils. For example old VW Beetles which have been run on normal single grade or multigrade oil and switched to Fully Synthetic have failed, because the detergents in F.S. dislodges accumulated sludge which has built up in the odd corner in the sump, which then goes on to block oil galleries. Perhaps it may be best to stick to what is already being used. I tend to go with what the OEM recommends.

Hi Chilgrove.
Only use the oil garde suzuki recommend in the hand book.
Or you might be look for a new Engine in two-year time
My jimny is a 02 with the same old nylon washer and it's still not leaking

Thank you for your advice. As this Jimny has not been serviced for a long time (before I bought it) I am using engine flush then new filter and oil. I have been pretty careful about the oil and have just bought Castrol Edge fully synthetic 5 - 40, the viscosity ties in well with the Suzuki recommendation.

I know what you mean about sticking as far as possible to the makers recommendation but nowhere does it say use semi synthetic, fully synthetic or even a more basic oil so I am fairly confident of not wrecking the engine with this stuff.
Chilgrove.

Hey

On the crush washer I recently changed the oil on my Jimny and tried to reuse the washer that came off, it immediately started leaking. I phone Suzuki and they posted me a new crush washer for a couple of quid.

I've now got the new part from Suzuki. It's not copper as I expected but appears to be aluminium or similar.
In case this is of use to anyone else the dimensions are approximately as follows:
o/d 20mm, i/d 14mm and about 1mm thick. Seems to have done the job nicely.

In case it helps anyone down the line arriving here from Google, for the Gen 4 the washer I just bought from Suzuki seems to be much the same:

aluminium or similar
o/d 20mm, i/d 14mm and 1.5 mm thick