so today i decided to perform a tune up on my disco II and I was only able to get 7 of the spark plugs out. The eighth (no 3 plug, second back on the drivers side) I was able to turn it about afull revolutionand then it got harder to turn I tried to screw it back in order to work it free but it would not go back. Ive got it soaking in penetrating oil right now but I fear that the previous owner may have cross threaded it.I need to drive it to work in the morning and im fairly confident its going to stay put, but I need to get it out at some point. Would getting the engine to temp help, I saw online that some people suggested that, but it doesnt make much sence to me as aluminimlike all metals expands when warm. My only other option is to force it out and hope and pray to the land rover gods that it doesnt sheare off leaving me with just a stump. If it came out and was crossthreaded I would need to retap it right? what should i do about and shaving that would end up in the cylinder? Any input would be greatly appreciated. I dread taking this to a repar shop but I'm willing to bite the bullet if thats the best option.

Thanks

 

May be that the plug, being a different metal will not expand at the rate that aluminum does...

 

If it does strip and you have to tap the hole dont worry about the shavings, they will disinigrate in the combustion chamber.
I think that you need to just apply more force to it. Make sure that the socket is on good and put a pipe on the end of your ratchet and apply more power. It will come out.

 

spray some PB blaster on the threads and let it soak as long as possible...the longer the better and re-apply a few times if possible.

 

If you do get it out, you can buy a plug thread chaser at most parts stores that you can thread back into the block and clean out any old threads, try to recover as much of the loose metal as possible.

 

I've seen manuals that say to take the plugs out when cold, I'm not sure why though. I've always had a much easier time getting stuck plugs out when the engine was warm. I'll also say that I've taken out quite a few spark plugs that I've been real nervous about because it took a scary amount of torque. They always ended coming out fine in the end though. If it started coming out already, you're probablygood to go. If you're wrench is less than 12" I'd bet you can't get enough torque to hurt anything, just be careful with a breaker bar though. Don't forget anti-sieze with the new plugs!