Sump Plug Fubar'd

[16_Valve]

So the Clio is long over due for an oil change... Took her to a local garage and put her up on the ramp. Had a look at the sump plug and it would seem that some grease monkey has over tightened it without using the proper tool. The female square insert (8mm iirc) is completely burred, stripped, messed up etc. Tried tapping various hex & torx bits into what was once a square hole, but it won't budge.

I've got a new one so that when I do eventually get the wrecked one out, there's a decent one to replace it with but don't want to go too mad getting the old one out because I think the sump is a soft alloy and I don't want to cause any hairline fractures being to brutal removing it.

Any ideas about the best way to get the old one out? i.e. heat? mole grips? etc.

Thanks in advance!

 

[pingpong]

Grind a slot or edge on one side of the bolt head so that you can get purchase with a punch or chisel and attempt to shock it loose?

 

[JoshE]

I used a screw extractor kit on a damaged sump plug on a bmw 5 series, worked a treat.

Something like this...
http://www.halfords.com/motoring/garage-equipment/tool-kits/laser-6-piece-screw-extractor-set

 

[16_Valve]

Thanks ^^^

Tried blow torch & grips to no avail. So I pushed the studded end of a long bolt with a 17mm hex head, into the fubar'd square hole of the sump plug & welded it to the sump plug.

Result! With the new bolt welded to the messed up sump plug, I just turned the bolt (and sump plug) free

Drained off the oil, fitted new OE sump plug & washer, new filter & filled up with 4.7 litres of fully synthetic 5w30 oil. The book say's 4.9 litres for the mk2 ph2 1.4 16v but I prefer to under-fill and top up if necessary than over-fill and and have the hassle of draining off the excess. Thanks for the replies!