Hi all changed my cat that was bad in my 4.2 yesterday. As I undid the two nuts that tighten it to the manifold one came out great the other fell off after half a turn with all the thread on the stud due to being so rusty.

Anyone successfully removed and replaced the stud? I’d rather not risk it snapping and just tap it down to an m5 if the success rate is low

Cheers Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Last edited by Danwilderspin on 9th Aug 2021 2:53pm. Edited 1 time in total

Only ever had luck if you have some oxyacetylene and can get it cherry red then use a proper stud extractor that will grip as much of it as possible...  Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Hmm might be worth trying to cut an m5 thread first Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Haylands,

I am getting a lean code on the bank with only one nut holding to the manifold I’m guessing this is expected if it’s slightly blowing?

It looks like this

Do I just need an inverted torx sockets for removal or something more special? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Yes, you will need the torx socket to fit the new bolt.
To start with, as above you may need to put some heat into the original first, this will also destroy or soften the thread lock compound if on the thread.

You could try locking two or three nuts on the thread, IF the there is any good thread left.

You could also try one of the below - lots of different tools around, the fourth one down is excellent for removing good studs with minimal damage.



https://www.machinemart.co.uk/p/17232-seal...installer/

https://www.machinemart.co.uk/p/draper-556...ce-stud-e/



Lots of shiny stuff to collect, hope this helps

Edit - If you already know all this stuff, please excuse the advice, I am still learning who has the spannering knowledge and who hasn't, on here.

What he said......

Leaking exhaust up stream from O2 sensor can give a lean code as it can draw in air from the blow then the O2 sensor thinks it's running lean..  Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand Sold
2002 L322 Vogue 4.4 V8 Epson Green (Fatty Offroader) Sold
-Click for Project Fatty off roader-