W221 glow lights stays on for longer

[ScoobyDooLondon]

About 2 weeks ago, the glow light indicator came on the instrument panel after starting the car.

Usually, it comes on initially and then goes away after 2 or 3 seconds.

Lately, it goes away but then returns a few seconds later, and stays on for about a minute or so. After this point, once the car is warmed up it doesn't return until the next day.

From what I've read, it could be either:

i) a single or multiple glow plugs that are faulty
ii) the relay could be faulty

I intend taking it to an indy, but from the above, is it possible to work out which of these scenarios it is?

If its a faulty glow plug, should I change just the faulty plug(s) or is it better to change all 6?

Whether its plugs or relays, what's the likely cost?

 

[sallison1504]

This usually ends up being the relay. However could still be one or more faulty plugs.

 

[ScoobyDooLondon]

I'll have to book it in to an indy.

If its glow plugs, what's the likely cost of replacing all six? And typically how long should they last? Something that should be done annually perhaps?

And how about the relay - again, what's the estimated ball park costs.

thanks all

 

[BIG_G_1979]

Had this problem on my w211 and it was a faulty glow plug. I changed all six for peace of mind. I bought oem beru plugs from ECP and at the moment they have a sale on whixh reduced each plug from 17 quid to 10.85 so it wasnt that bad cost wise I changed the plugs myself as it wasnt that hard to do

 

[t-dawg1]

Had this problem on my w211 and it was a faulty glow plug. I changed all six for peace of mind. I bought oem beru plugs from ECP and at the moment they have a sale on whixh reduced each plug from 17 quid to 10.85 so it wasnt that bad cost wise I changed the plugs myself as it wasnt that hard to do

Can you send me a howto instructions to removing glow plugs on these

 

[ScoobyDooLondon]

Actually, I've noticed that the engine struggles a little before it turns - does that point to a glow plug or relay problem?

 

[BIG_G_1979]

Actually, I've noticed that the engine struggles a little before it turns - does that point to a glow plug or relay problem?

Yes that would indicate plugs as fuel is not heated and wont burn hence a delay in starting

 

[BIG_G_1979]

Can you send me a howto instructions to removing glow plugs on these

Hi tdawg, I dont have a how to but it is fairly easy (mines a v6) its just a matter of removing the Y air intake from center of engine then disconnecting the glow plug connectors u will need to use a long deep 8mm socket on a extension bar its a bit fiddly but diy doable. Just make sure u soak them with wd40 prior to trying to remove them as they can snap.

 

[KeithJG]

I had the same problem glow plug light coming back on after starting for one minute then go off while engine running.
I ordered a new relay but when getting the car just serviced number 5 glow plug was faulty ...it was changed and now the light is only on for 5 secs and it starts straight up with no light .....so i have returned the relay!