My wife's 05 CDI, with 88,000 shows a Check Engine light and the glow plug symbol stays on after start. My scanner shows a P0672 fault, which is the #2 Glow Plug failure. I re-positioned the wire on the plug and the fault still remains. The car is under the extended warranty. I read a DTB that seemed to indicate that if one fails, they are supposed to replace all of them. One dealer I called said they only replace the failed one. Any thoughts?

 

Called my regular service MB dealer and he said they usually replace them all. Also, for non-warranty DIY work, I am quite nervous. There is a procedure where if the NM exceeds a certain amount when you are taking them out, you are supposed to heat the engine to help loosen them! Plus, they go into an extended procedure in case they crack ( ceramic ) and you have to drill them out. I think I will always let the dealer do this kind of work.

 

if it is a benz extended warranty they will repace all of them. if not then they may only do the failed one.

 

Dealer found #2 Glow plug had failed and others had some bad resistance. All were replaced. It was submitted for the extended warranty and refused. I had to pay $625. 3 hours labor@354, parts$226, tax and shop supplies. It was an MB extended warranty and the dealer said that it was a "consumable".

 

Ouch!

Is this reasonable?

 

Well that is kind of hard to say. The dealer price is in line with what other forum members have paid at various dealers. What is kind of interesting is that the parts cost about $225 and the rest is labor. I guess if you are careful and get lucky, you can get the glow plugs out without breaking them. You then have to clean the recesses with a brush to get the carbon out. Benz has some kind of brush kit they are supposed to use. If you get unlucky and break one or two, you have to have a kit to get them out. My original glow plugs lasted about 4 1/2 years with a lot of starts. You have to balance the risk of doing it yourself vs paying the charge maybe once each 4 or 5 years. The failure code also lights up the Check Engine light which has to be reset. I have an Autoenginuity diagnostic program that can reset the light, but I did let them do the job this time.