Could any of you kind people tell me what size socket or spanner I need to use to remove the oil sump bolt.

Thamks

24mm.
Hex (6 sided) is much better than 12 sided.
If it hasn't been removed for a long time it can be very very tight and a real PITA to crack.

Do yourself a favour and replace it with a 380 sump plug.

Thanks guys

Do yourself a favour and replace it with a 380 sump plug.

I quickly searched but got too many results, so - what is better?

Does it take a smaller socket than 24mm?

It would make life a bit easier if it did.

Yep, the 380 sump plug is much smaller than 24 mm, it's 14 mm IIRC.
But the main thing is that it has a long land, plenty for a socket to get a grip on, whereas the stock Magna plug has a very small land.
Combine the small land with a slightly recessed hole and it's very easy to round off the stock plug, I've done it and it took many hours and a visit to a mechanic to then crack the plug.

I've had a quick look on Ebay using Mitsubishi 380(obviously) sump plug as the search term.

I am seeing lots of results with "14x1.5" thread.

Without me taking out my own sump plug on my TL(I just changed the oil 2 weeks or so ago - not due again for a while) and measuring it with my pitch gauge, is this the correct size thread?

I should be able to find plenty at the wreckers on my next trip, without having to buy anything specific, or is it necessary to find one that has an "O" ring like my current TL plug?

Fortunately, I didn't have extreme difficulty(only some) in taking mine off, but I was just lucky I had a 24mm thick wall socket....the only 24mm tool I had.

22mm or less.....lots of choice.

The 380 sump plug thread is the same as the stock plug thread, it fits perfectly.
Don't worry about getting one from a wreck or over Fleabay, they are cheap as chips brand new from a stealership, around $4 IIRC.

Yep, the 380 sump plug is much smaller than 24 mm, it's 14 mm IIRC.

Its a 17mm head, but I agree, its a worthwhile swap from the original. I was always weary of rounding off the larger ones before fitting a 380 sump bolt in its place.

The 380 sump plug thread is the same as the stock plug thread, it fits perfectly.
Don't worry about getting one from a wreck or over Fleabay, they are cheap as chips brand new from a stealership, around $4 IIRC.

Yes, that's much more like it.

Thank you.

Whatever plug you use put some anti-seize on the thread - makes life so much easier next time - and won't cause a leak.

That's a good idea which I have not heard of before.

It just so happens that I have a tube of Permatex anti-seize that sees not much use other than for spark plugs.

380 plugs also usually available from Autobarn, Repco etc.

That's a good idea which I have not heard of before..

My other car is a Jaguar XJ-S - sometimes I need antiseize on my brain dealing how rusted, busted or stuck bits can get on that car - so it becomes a bit of a habit to add a smear of Antiseize to anything metal on metal.