Didn't know it was a cast sump, from a photo there is obviously something wrong, bolt doesn't look right in the hole.

I would maybe get a new sump plug from the dealers, then at least you will know whether what you have is right or not

You may then be able to identify the thread to maybe helicoil. Regards
Royston

2008 4.2 Supercharged Autobiography
1994 Classic Vogue SE
1999 Rover BRM
1987 Rover Vitesse Twin Plenum

Hope that the old threads aren't just floating round the sump!

That is not the right bolt, it does look like someone has had a problem before and just bodged in a standard bolt. There is nothing that can't be fixed with a hammer😜😜
FFRR 4.4 SDV8 Autobiography Santorini Black.
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My thoughts exactly about it being the wrong bolt & this is the first time I've even looked at a L322 sump bolt. I'm now in two minds what to do, the bolt is back in & tight & I need to get the car moved off the drive ASAP to bring my classic back to go on the drive. But at the same time I hate things being bodged & it will bug hell out of me & also if I just put oil in to move it then if I do decide to sort it then that's a waste of a load of new oil. 2004 RR 4.4 V8 Autobiography

Put oil in and fix it when its next due an oil change

Yes I think that's what I'll do

I'll drop a little oil in first to see if it leaks as a test, don't want to fill it right up to discover it's now leaking  2004 RR 4.4 V8 Autobiography

I can't remember the thread of the Bmw engine - but I bought a clever magnetic tipped sump bolt a while back. I think I got it on eBay for about £4..... I googled the engine type to find it. This has a magnetic pull on your engine oil to hold swarf to be cleaned off at oil changes. -so you could buy another size up from the one you have, and tap a thread, using tap cutting grease. - that bolt in the pic looks very 'foreign' I think your stripped threads are on the end of the new bolt, stopping it from dropping out.

That is an ordinary 8.8 high tensile bolt / setscrew which some idiot has put two copper washers on.

I'm guessing its M12 so you could tap it out M14 and repair it that way or get the nearest helicoil size up from it.

^^ Wot he said, or you could tap it to 3/8" BSP which is 14.25mm ish, at least you'd be able to get a blanking plug in the bsp size. First I'd see if you can get an M14 blanking plug as that will require less material to be removed from the hole. Oh and be warned that metric treads come in different pitches, there are 4 14 x 1.00, 14x1.25, 14x1.5 and 14x2.00 Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

You could try this

http://www.malpasonline.co.uk/itm/Metric-H...amE8J.dpbs Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

I was thinking if you have to go to the effort of recutting you sump thread how about going whole hog and fitting a quick drain plug ?

http://www.quickvalve.co.uk/ 2008 MY Supercharged
Rimini Red / Jet
four zone climate
remote park heater
and no ugly kid windows.
magnus satis quod turpis satis

never seen one of those before, neat idea

The only draw back that I can see, is that it does not swivel, but in hind sight, that will turn out to be an advantage in this case, as you will have to glue the drain plug in the sump at the correct angle. If any of the threads have survived the assault from the chimp that bodged the sump plug, and presumably ate the original plug ( ), there would be no need to re-tap the sump. I would suggest the use of JB Weld to glue the plug in the sump, and you will have to use some de-greaser to clean the hole. Here I would recommend an aerosol of brake cleaner or carb cleaner, which will be an industrial alcohol based solvent, in a squirty can, so no problems with application

The only other issue that I can foresee is, you will need to raise the car at an angle so that the sump plug hole is above the sump, otherwise the de-grease will take a life time as you clean out the whole sump

And obviously you'll have to do without the use of the car for a day while the glue sets , but it's a small price to pay for never having the a55 ache of removing the sump plug again, and oil running down your arm will also be a thing of the past

I think that I will look in to fitting one of these, as I can only see advantages, and no draw backs. Does anyone know the original thread size used in the BMW sump (TD6)? Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

^^ Don't answer that, they have an application list that includes all the ffrr models

LOOK http://www.quickvalve.co.uk/f109n_details.htm

Even better, you fit a hose and make the old oil go where you want, and not where the wind will take it  Yesterday I couldn't spell Engineer... Today I are one!
Inventor of the 'Guide-o-Matic automatic wheel alignment tool'
Former long term L322 owner, Up/Down graded to a Classic Tractor!

That quick valve looks a good solution. I've actually screwed the plug back but it leaked slightly so I used jb weld RTV silicone round the plug for now. Was going to tackle it next time as lots more issues I'm trying to sort out but I may order one of those. 2004 RR 4.4 V8 Autobiography

I would sort this as a TOP priority - If that fails and the bolt comes loose you could be in a world of s***

So, if you fit a quick drain valve, what is to stop you knocking it very time your under the car doing maintenance? And covering yourself in engine oil???