Have you tried an Allen key mounted in an impact driver, similar to getting disc screws out. The extra whack from the hammer on the driver may take the key further in to reach part of the hex that hasn't been rounded off.

If no good I'm with the others on the bigger hammer and harder whack. Shape your chisel with all the taper on one side so it bears at just the right spot at just the right angle without resting on the casing as well. Gently tap at it to raise a good lip that the chisel can get a good purchase behind and then as hard a whack as you can muster.

If you do need to drill; drill and tap the new thread before drilling right through the bottom, and use the smallest size drill to break through that is compatable with getting a filling nozzle through. Keep blowing off any swarf and have your drill covered in grease to catch as much as possible. A 3/8BSP taper plug looks about right to fit in if I'm scaling right, that's about 5/8" OD, and should give you a nice hex head for 60K's time on the next change!

I'd be going at that a bit more with the hammer and chisel. Alternative would be something like locking key remover - you'd get a suitable size on to that I reckon and with enough force it'll come out.

Hammer + Chisel should give you something resembling this:

See, that's why I love this forum. Loads of dead useful advice. Ask on the Kia forums and you just get tumbleweed blowing past...

No problem; you've contributed to the collective knowledge on here - this is our payback. A picture of the mangled remains of the plug and what finally worked always goes down well.

NikTheGeek said:

See, that's why I love this forum. Loads of dead useful advice. Ask on the Kia forums and you just get tumbleweed blowing past...

Click to expand...

How are you getting on? If you use a hammer and chisel to start with and then(if you have one of course) a blunt air chisel usually will do the job.