threaded glow plugs help

[muddydude]

Hi Guys.
Just a quick one for some advice.
Had my 2.2 dti for about 2 month now so i decided to change the glow plugs.The first 2 came out ok but the third turns but will not come out.I think this one is stripped the fourth one will not tighten so this must be stripped threads aswell..first of all is it ok to run the car like this untill I can get them fixed as the engine still works great and second how to fix the problem
Many thanks in advance
Chris

[Critch]

Wouldn't suggest running it like that for any length as it could cause more problems. But you need to get old ones out and get a helicoil insert in. Making sure no swarf goes into combustion chamber