W211 Om642 Glow Plugs Question

[expandyman]

Had my glow plugs replaced this week for the 1st time in 10 years and 87k. Curious as to why the two remaining good ones (Resistance <1 Ohm) are still look bright and almost as new, where as the dead ones are quite heavily corroded. Is this normal or indicative of some other fault lurking ?

 

[wu56Shoozz]

It would suggest that the later two have been replaced recently hence still clean.. the good news is that you got all six out without problem as I'm told that they can be quite a Bar Steward to do and can break in the head... I don't see there being a problem to worry about just as long as it starts properly now in the cold.. I did mine too but was advised to change the relay also as its that that causes our problem......

 

[Jonesy161]

Is it not to do with the cleaner burn of the good plugs, hence the coke build up of the failing ones?