CLK 270 CDI pre-heat glow plugs, advice please

reggie musson

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I have no user hand book for my lovely 2004 W209 so can anyone tell me if I should turn on the ignition and let the glow plugs warm up for about 5 seconds before starting the engine, as with other diesel cars I have owned?
I notice what looks like a pre-heat glow plug orange symbol in the anolog clock face comes on after I have started the engine and then goes out once I have covered about a mile.

Any advice please, Reggie
 

Cabe

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I usually let the glow light go out, this usually takes between 5 and 10 seconds depending on the ambient temp. I don't think yours should be on for that length of time, I think you need to get it into a specialist for a proper STAR diagnosis.
 
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R2e

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That means (at least) one of your glow plugs needs replacement, I had exactly the same with my C270CDI. A new set of plugs solves the problem.
 

SPX

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You have at least one glow plug that needs replacing.

I've known some Sprinters with the same engine as yours go a year without replacing the plugs that needed to be renewed.
 

gtvlusso

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I think that there is a glow plug tester in the engine bay - in the fuse box. You can test to see which one is knackered and replace it. Nearly always the most difficult plug to reach at the back of the engine, of course!

Just remember that they have probably been in there a while and will need a bit of teasing out. If you are not sure, take it to a good mechanic. Glow plugs can get jammed in and then strip the threads on the head when removed - rare, but it is a nightmare to fix!

Are you saying that the "piggy tail" glow plug light takes a while to go out, or the little orange light within the speedometer takes a while to go out? They are 2 different things....
 
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reggie musson

reggie musson

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When I turn the ignition on the glow plug light doesn`t come on, its only comes on when the engine has started and stays on for a mile down the road as I mentioned.
Reggie
 

WG M-B

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Trouble is the glow plugs very often short and blow one of the fuseable links in the control relay. If this has happened then the light will remain on afterward replacing the plug. Its best to get someone to check the relay as well. Its very simple and can be done with a multimeter set on ohms by testing across the pins which are the outputs to each plug
 

gtvlusso

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When I turn the ignition on the glow plug light doesn`t come on, its only comes on when the engine has started and stays on for a mile down the road as I mentioned.
Reggie
Definitely a duff plug!
 
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reggie musson

reggie musson

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Thanks everyone, having the plugs checked next week with a service.

Reggie
 

Jas johal

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I'm having this problem too had plugs and relay checked garage said all fine, they said is a more complex electrical fault. Please help I'm new to this site
 
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reggie musson

reggie musson

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The garage found a fault with No 3 & 5 glow plugs, so I had the whole set changed and has solved the problem:thumb:, if it didn`t I would of had to go to MB.
Reggie
 

Robert-Black

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Sorry to piggyback, but just wondering if my glow plugs are ok also, never having owned a diesel before.
On with ignition after about 4/5 seconds the glow plug light goes out, then on start it usually but not always comes on again for about 10 more seconds before blinking off again.
 

Dieselman

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That sounds like you have a blown plug, check with a multimeter.
 

Robert-Black

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Thanks Dieselman, i will check the warranty, if its not covered i'll read up and fix it.
 

Jas johal

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So 9 times out of 10 is it normally just the glow plugs???
 

Bobby Dazzler

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Were the replacement parts from MB or somewhere else?

I recall that in a small number of cases the light comes on as a different part in the pre-heating system fails, but it's much less common than glow plugs.
 

Jas johal

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And normally I always go to main dealers in derby but funds were a bit tight so I used a Benz specialist for glow plugs, can't remember the brand but they were still meant to be good ones cost £145
 

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