Glow plug light comes back on for 20 seconds

[fwb44]

When starting the car from stone cold I'll turn the ignition key so all the dashboard lights come on, wait till the glow-plug light goes out, start the engine (which takes 5-6 cranks), then after about another 10 secs the glow-plug light reappears, remaining on for a further 20 secs. approx. At all times the car seems to run perfectly normally but - what does this reappearing glow-plug warning light signify? If there's a connection, since a new MAF sensor was fitted at the last service 1000 miles ago, average MPG has dropped from 41.5 t0 37.7 under identical driving conditions. Any thoughts?

 

[psmart]

Check out the threads.....
http://forums.mercedesclub.org.uk/showthread.php?t=15996
and
http://forums.mercedesclub.org.uk/showthread.php?t=9776

Basically, a glow plug or two have gone. You can either do it yourself (read the threads to procedure and hazards) or get it checked into a dealer or indie with a glowplug rebore tool, just in case they snap one!

 

[fwb44]

Thanks psmart, that's exactly what I needed to know. I think this is one for my local indie ... the local M-B dealers, a complete bunch of clowns, sheared off two of a colleague's glow plugs recently and ended up having to give him a cylinder head replacement job and a loan car - but he had always had his car serviced there (triumph of hope over experience if you ask me)

 

[OlafMaxwell]

The glow plugs regularly shear/break. This is a very common comment here so its best to get that job done at the stealership.

 

[Coulsdon Eagle]

Being such a common (and potentially costly) fault, you'd think after all this time, MB would have come up with a solution to this wouldn't you? or is it left like this to extract as much money out of us as possible? after all, a reliable vehicle doesn't make them any more money, cynic? me?

 

[fwb44]

The glow plugs regularly shear/break so its best to get that job done at the stealership.

but my point was precisely that the dealership screwed up bigtime on this job for my colleague - ok he got a free replacement cylinder head & loan car for the duration out of this mess, but was that what he set out originally to achieve, especially given the supposed relationship of trust he thought he had built up by having his car serviced there every time ...