Hi, I had B service done on my 2001 ML 270 CDI. I had my glow light coming on after I start the engine but it would go off after 40 sec. I told that to the mechanic and after checking everything he said that one of my (5th) glow plugs is not working. He tried to replace all five of them but he couldn't remove plugs on 4th and 5th cylinder because they are stuck. He also said that the car is working on 4 glow plugs and that I'm better off leaving it the way it is cause if the plugs shears it's gonna cost me a lot of money to fix the car. The only thing now is, after I start the car the glow light comes on and stays on and it doesn't go off until I turn off the ignition and when I start again it comes up and goes off after 40 seconds. I don't know what to do. Can somebody explain what is going on, how and where can I fix the problem and how much are we talking about? I live in Ireland if you can recommend anyone. Thanks.