[crew1992]

My car started shaking at idle and I took it to a shop that only deals with BMWs. They thought it was a bad coil or spark plug in the #6 cylinder but the coil checked out fine. They then took out the old spark plug and said it had a piece that was broken on it. Well, the old spark plug was taken out and they tried putting in a new spark plug and it went about halfway and is now stuck there. The shop also did a compression check and all checked good expect the #6. The rest were less then 8% and the #6 was 60%.
The shop then quoted me $7100 to repair the valve. I am thinking of taking it to another shop to get a second opinion on it. What do you guys think? Any advice?

[Noz1974]

I think your engine is shaking because you have low compression on 6, this means that your no 6 piston is in effect dead weight being carried round it's cycle by the other cylinders causing an imbalance. I suspect you have a broken or damaged valve or maybe the piece of the spark plug is stuck on the valve seat stopping it closing after the air/ fuel has entered the cylinder, hence low compression. The price you have been quoted sound ridiculous. Buy a workshop manual and remove the head yourself or get another garage to do it, then you can find out what the problem is, an engineering shop can help you get the valve seat re cut, replace the valve guide and fit new valves, sounds like you need them to re thread the spark plug too, did the garage cross thread it, that is usually the only reason it will stick half way, it is quite easy to do as the thread is quite fine, they should be started off by hand before using a wrench, but get the head off, you also need to check the piston and it's bore for damage if there has been debris in there, hope this helps!

[Bmoney2K4]

my dad's ok 525i has the same issue. The car has been to the dealership many times but nothing has been solved. I think it is a faulty engine especially considering it was in its first year of production for the 06 models of the 325 /525