Lambda sensor hard to change

[rendoman]

Hi all and happy Holidays!

This night, 26 dec, I decided to change my lambda sensor of my Golf mk3, having bought a new fresh sensor from Bosch Germany (made in Usa ). Big trouble: 18mm thread (long about 5mm) welded to exhaust manifold!
I tried svitol, long poligonal wrench (22mm), nothing! So I decided to dismantle fuel manifold in order to gain some space over the sensor. Unluckily manifolds are close to windscreen, with no chance to work under the car or use an hammer or impulse screwdriver.

I'm thinking about warming manifold area with oxigen torch (cutting torch can be useful instead of welding torch 500lt\h?). There are some cooling system tubes around, maybe I can shield area with aluminum plates.
Last chance solution I think is to demount exhaust manifold and try bad things on the table... but I really don't want to do this

Any other good idea to disassemble the lambda from old manifold?

[olderdan]

Hi rendoman
I have had a lot of success with the boiling water method to free rusted items in the past. The idea is to expand the housing before the heat gets to the offending part, (this happens very quickly) if you have used penetrating fluid ( i'm sure you have) get a third hand to pour the boiling water around it while you apply any spanner you can get on it, you may have to try a couple of times after letting it cool right down each time.
At least this wont damage surrounding parts so worth a go.
I used to remove the the taper rear hubs on my Scimitar like this after reading about hydraulic pullers flying across the workshop and this way they would just fall of in my hand.
Good luck

[rendoman]

Mission accomplished!
I used 250lt\h cutting torch, I cooled the old sensor with fresh water during heating. Little force needed to unscrew the lambda. It took a bit of time searching position of some bolts, job done in 5 hours more or less.

I found also an old rubber tube (oil vapor recovery) a bit damaged, changed with a fresh one. Now the car is running as new! I had bad troubles with idle rpm, particularly with cold temperature and cold engine. I changed also coolant bulb temperature, cleaned throttle body and injector, settled idle step motor.
A good work!
Thanks for the method of boiling water, I'll keep in mind for next delicate work
Saluti
Stefano