glow plug light

[LeeW]

Hi,My C250 1996 shows symtoms of glow plug failure (runs rough for a few seconds after startup,clouds of smoke) yet the glow plug light does not come on afterwards to indicate a problem.Could it be something else,or is it not unusual to have plug failure and the dash light not to come on?The light comes on and off to show pre-heating.

 

[television]

Faulty glow plugs will show up on fault code read out with the 605 engine

Malcolm

 

[Ian Brown]

Hi,My C250 1996 shows symtoms of glow plug failure (runs rough for a few seconds after startup,clouds of smoke) yet the glow plug light does not come on afterwards to indicate a problem.Could it be something else,or is it not unusual to have plug failure and the dash light not to come on?The light comes on and off to show pre-heating.

Does the car start easy or does it take a lot of turning over before it starts doubt its a glow plug when light doesn't light after it is started.

 

[LeeW]

Thanks for replies,the car starts ok Ian, just runs rough for a few seconds afterwards.However if the temp drops to near or below zero then it does take a lot of turning over before firing.

 

[Cooky]

Thanks for replies,the car starts ok Ian, just runs rough for a few seconds afterwards.However if the temp drops to near or below zero then it does take a lot of turning over before firing.

This could be a symptom of air leaking into the fuel lines around the filter/fuel heater. Apparently it is a known problem with the 250/300 diesels. I had exactly the same symptoms with my 250 Turbodiesel (I had to call the AA out twice and the car would only start by spraying easy start into the intake).

Mine ran OK for a week until the temperature got down to around freezing, and then failed again. I took it to an independent MB specialist in Bristol and he changed all the plastic pipes, O rings and fuel heater, and the problem has gone away.

It seems that this may recur in about 6 years time.

I hope this helps.

Cheers and beers

 

[tjo]

if only 1 glow plug is faulty warnin light will come on aftr start but if more than 1 is faulty light works normally again just to confuse the issue, certainly sounds like a glow plug prob

 

[Ian Brown]

if only 1 glow plug is faulty warnin light will come on aftr start but if more than 1 is faulty light works normally again just to confuse the issue, certainly sounds like a glow plug prob

It doesn't matter how many glow plugs are out the light will illuminate after the engine is running I put 4 plugs in a friends 190 2.0 diesel as the old plugs were us 4 and light was back to normal. With the old plugs in it took very little time for the glow plug light to go out.

 

[tjo]

hi ian your talkin about an old 601 engine on the later m'valves in our experience light acts normal if more than 1 plug is faulty

 

[LeeW]

thanks

Thanks for helpful replies guys.I'll have a go at changing plugs,normally a straight forward job but as I'm sure you know on this engine you have to remove inlet manifold.Cheers Lee.

 

[Dunx]

I seem to remember reading somewhere that the glowplug check function (on my W210) checks the plugs in pairs. If an odd number (1,3,etc) of plugs are u/s then the glowplug light will illuminate after the engine has started. If an even number are u/s, the light will behave as if all is well. Not 100% sure this is correct, but I as I said i remember reading that somewhere.

 

[tjo]

you can check how many are faulty by pulling off multy plug off relay on n/s wing and check resistance, the wiring goes straight to the glow plugs, the number of each cyl is also marked on the multi plug but look carefully its tiny print. you relay may be under washer bottle