1997 E Class 300DT: Glow Plugs!!

[Kevincent]

I would appreciate any feedback on Glow Plug performance. I am about to deliver my E Class 300DT with 125,000 miles to the servicing dealer who has already replaced 10 (ten) glow plugs over the last four years at a total cost of £750.
My symtoms are that the heat indicator on the dash re-lights after starting and the engine is very "lumpy" for a minute or two. In desperation I took the car to a local MB specialist who assures me the Glow Plugs are OK although these symtoms are the same every time. Specialist has referred me back to dealer for "proper" diagnosis.
Any ideas out there please?

 

[dieselman]

It sounds like there is a glow plug down.

At a long shot it could be the relay unit itself or a bad connection to a plug or one of the leads, but I don't think so.

Incidentally have the replacement plugs always ben the same ones each time ar random burning out.

If your dealer is replacing the plugs one by one then he is ripping you off as the labour is what costs.
Only use genuine plugs, which are about £20 each from MB dealer. A full set fitted is about £250.
The control relay is on the n/s inner wing behind the washer bottle. Each plug can be metered in turn from the big connector.

If you fancy doing this job yourself I have previously posted the instructions. search the posts. Come back if you need more info.

 

[Kevincent]

Glow Plugs

Many thanks for your help.
To answer your questions:-
Relay and glow plugs:
My MB specialist tested the relay and each of the exisiting glow plugs and reported them OK.
Which plugs fail:
The dealer only started keeping records after the last replacement when four were changed. I had asked that all six be replaced but they said that two were seized and working so only four were replaced - even though I was charged £120 to remove and refit the outlet manifold.
Thanks again for your comments and Yes, I have located your DIY instructions!

 

[dieselman]

Aha!
I think you have the answer in the two plugs not replaced.

 

[piestore]

heater plugs

Hi
you are correct in assuming that it is probably a heater plug fault as you say it is easyier to remove the inlet manifold when changing these, for this reason it makes sense to change all of them at them same time. One or two of the plugs can be changed without removing the inlet manifold (1,4 & 5 I think) if you have been useing MB parts they carry a 1 year warrenty,

regarding the seized heater plugs the best bet is to get the engine mad hot remove the inlet manifold quickly get a good single hex deep socket and try to undo, be prepared for the plug to snap. Next remove Cylinder head and send to engine shop to have plugs removed. I would guess that 90% come out if the engine is hot

 

[Kevincent]

Glow PLugs

Thank you for the advice.

I am hoping that the faulty plug(s) will be one of those replaced last may and will therefore be covered under warranty - although I guess sod's law will apply!

Thanks for the tip on heating the engine to remove the seized plugs. I won't try that myself but will encourage the dealer to consider it!

I have written to the dealer principal concerned to ask for his view on the matter - might be interesting?

 

[dieselman]

I'mm sure his view will be.

"Please bring the car in for an inspection and remedial work, then please bring in your cheque book / overdraft."