V6 CDI glow plug light ...

[BTB 500]

OK I have the glow plug light coming back on after the engine has started, then going out after a minute or so. Is this likely to indicate a problem with a plug? The engine starts and runs fine, no faults listed on the cluster display. It's only done approx. 35k miles.

TIA

 

[corned]

I believe so. You would be very unlucky to get any real starting problems though, even in the depths of winter, because you still have five to pull on. One down out of six is not enough to cause problems. However, if a second one joins it...

 

[Jukie]

And if it comes to it, remember the maxim: "replace one, replace all".

 

[Danny DeVito]

I think on my vehicle when this happened i left it and then the plug shorted and now has damaged my relay again. I am soon to check plugs and hopefully repair the unit again. Thats my best guess anyway, Happy Halloween, too late but anyway

 

[Danny DeVito]

And if it comes to it, remember the maxim: "replace one, replace all".

Add on the end of that, test the new ones before you fit them too.

 

[crockers]

The plugs are around £15 so not expensive. It's the labour that's the killer. You're looking at around £150. So it makes sense to change them all. Then they all come with a 2 year warranty.

I'm assuming your car is out of warranty.

 

[Oteda]

My car has the same problem, but Mercedes have changed the glow plugs and the light still behaves the same way.

 

[prm]

Had one of mine renewed by MB main dealer for £53 all in. When i asked if they all needed doing, he said not to bother, the others might last for ages. I had exactly the same symptons as you.

 

[mobeyone]

Mine had this light but the garage changed them all and the relay, problem solved.

Noticed mpg suffered as I was getting mid 25s but after 30s round town.

 

[BTB 500]

Thanks guys. It's on the Vito, 4 years old so out of warranty.

 

[Danny DeVito]

My car has the same problem, but Mercedes have changed the glow plugs and the light still behaves the same way.

Doesn't that prove that you should test them first ? 2mins vs how ever long it takes

 

[jaymanek]

The relays often go with the plugs on these. Not too expensive though.

 

[Oteda]

Doesn't that prove that you should test them first ? 2mins vs how ever long it takes

They tested them and said they were fine.

 

[Oteda]

Mine had this light but the garage changed them all and the relay, problem solved.

Noticed mpg suffered as I was getting mid 25s but after 30s round town.

On my W221, I am getting 25mpg round town, should I be getting more?

 

[mobeyone]

On my W221, I am getting 25mpg round town, should I be getting more?

I have a heavy foot and easily get 28mpg in moderate stop start traffic... it does dip to around 26ish in heavy traffic but as long as I am moving 28 is the norm.

I had over 40mpg on a run to Birmingham and that was at 80ish all the way.

 

[effbee584]

OK I have the glow plug light coming back on after the engine has started, then going out after a minute or so. Is this likely to indicate a problem with a plug? The engine starts and runs fine, no faults listed on the cluster display. It's only done approx. 35k miles.

TIA

Had this on my IL 6 320cdi for over a year, Star showed the faulty one, changed for £45 by local indie just to stop it happening.

Easy fix

For MPG, 40-45 on long runs, see my album 'My Mercs'

 

[Paul64]

What gives the glowplug system the instruction to turn off - the light to extinguish on the dash before starting?
I have the W124 300D lamp that stays lit for perhaps 15 seconds whatever the temperature of the engine though the engine starts perfectly after 5 secs pre-heat.
I swapped the relay with a mate's with little difference so I guess perhaps there's some sensor that detects engine temperature that's gone West???

Thanks

Paul

 

[john b]

2006 Merc 320 CDI.
Glow plug light staying on for about a minute after initially going out.
This was happening to my car so I had my local merc garage change all 6 glow plugs, that has cured the problem.
Cost 6 x £14.40 for the plugs and £72.00 for fitting, all plus VAT of course, but well worth it as I have read that sometimes the plugs are difficult to remove

 

[panason1c]

The relay, which is a sealed unit, has fusible links inside...........if the g/plug light is still coming on after replacing the plugs just open up the relay and solder some fuse wire across the broken link. (as i have done to mine).........far cheaper than buying a new relay!

 

[tonywashere]

OK I have the glow plug light coming back on after the engine has started, then going out after a minute or so. Is this likely to indicate a problem with a plug? The engine starts and runs fine, no faults listed on the cluster display. It's only done approx. 35k miles.

TIA

Had similar with my 2002 bus 90k miles, no problem with starting but replaced all four plugs anyway.