Thanks for that , there seems to be too many things that could be causing it , as the car is running well Yesterday, I rummaged through the gash box at work, found a 13mm bolt, stud sat in the hole, head sat against the plug. Welded onto the plug, the weld failed and the head just sheered straight off. Too much torque for 13mm. I used a chain strap wrench on it but it was slowly destroying the filter, I spent an hour or so trying to move it and eventually resorted to my home made sphere removal tool which uses double motorbike chain, eventually with a 3' breaker bar I got it to shift. However they had got it that tight I am at a loss to know.

This change of mind return policy is in addition to, and does not affect your rights under the Australian Consumer Law including any rights you may have in respect of faulty items. To return faulty items see our Returning Faulty Items policy. my citroen book recommends either TOTAL QUARTZ 7000 10W-40 Semi Synthetic or TOTAL QUARTZ 9000 5W-40 Fully Synthetic The worse job was on one of my recently acquired 406s, I say recently although I have had it for over a year but this is the first oil change I have done as it had just been serviced when I bought it (so I know who to blame). The sump plug came undone OK but I couldn't get the filter off, I only ever tighten them hand tight and you usually unscrew the by hand but this one wouldn't move. My Megane 1.5 dci is due it's oil change soon, so I thought I'd do it myself, the weather was nice, SWMBO was doing my head in, no better time to do it than this weekend.Last time I replaced the spark plugs I noticed the ignition cassette was corroded on the terminals under the rubber boots where it connects via springs to the spark plugs - I eventually replaced the cassette and noticed the new one had like spark plug top terminals at the springs instead of what looked like the end of brass bars. Prior to this fault code P1327 came up once which an internet search suggested could be the ignition cassette.

When the injectors failed it hardly ran, the misfire was very bad as you would expect if 2 cylinders were not working, so it is unlikely you have an injector failed. Suggesting to seal the washers was a preventative measure.Having a closer look, the plug was rounded out to the point where nothing works to get the plug out.