glow plug fuses c250

[pivers]

hi
i'm in the process of changing a glow plug on my 97 c250 td.
while testing each plug [the present ones have only been in for about 20,000 miles] I accidentally shorted out one of the it leads which is now dead. From the forum I have learnt that the relay has a fuse but i can't find it. all the other leads are working ok so I presume that this model must have 5 seperate fuses rather than one big one,assuming, that is, that the relay isn't broken. I've checked all the usual places i.e. under the bonnet and next to the battery in the boot....
Also, the plug which I am attempting to remove refuses to budge. A mechanic friend of mine says that the only thing he can suggest is refitting the manifold etc and warming the engine up and trying again. seems a bit of a chow to me but i'm open to any advice that anyone can give.

Grateful for any assistance,
pete

p.s.
there is no inlet manifold to cylinder head gasket fitted. is this normal and if so should i use paste when refitting?
thanks again
pete

 

[exeng]

stuck glow plug

Your mate is right but you can use a high quaility release oil but generally it is the element on the bottom of plug that causes the plug to sieze and unless you can get it to turn a little the oil will not get past the taper seat of the plug.There are loads of info on this on the forum any more info needed just ask

 

[Bolide]

On the 606-engined cars you can run the engine without the inlet manifold. On your car it wouldn't see any boost but I can't see there being a problem running it up subject to the usual caveats

The fuses are inside the relay

Nick Froome
www.w124.co.uk

 

[pivers]

thanks a lot guys. I didn't expect a reply so promptly although I was hoping for one. I'll be working on the car first thing in the morning and I'll let you know how I get on.
In retrospect I suppose I should have known that the relay fuses would be in the relay but I have to confess It didn't even occur to me.
thanks again
pete

 

[pivers]

checked the relay but no serviceable fuses as it is a moulded assembly. nick didn't actually say that they were serviceable so perhaps thats what he meant. noticed that there are six leads coming from the relay so i've used the spare one. don't know if this will work though as, when i was warming the engine up to remove the glow plug [which sailed out] i noticed that the glow plug light did not go out at all.

 

[Parrot of Doom]

It may be moulded but that won't stop you cracking it apart. The fuses will be inside and likely will look a little bit like this:

Just get a hacksaw and cut it open down the seams. Once you're done, glue it back together or wrap self-amalgamating tape around the seam.

 

[Parrot of Doom]

BTW, if they're the same you can have the old relay in that picture for a tenner + postage. I have no need for it. There are 3 working fuses on the other side:

They're soldered in.

 

[pivers]

thanks P if they are the same and i can't fix mine tenner sounds great to me. wish i'd known this morning about splitting relay though. pouring now and i'm working on the drive.
cheers
pete

 

[pivers]

been snowing heavily here so didn't get round to fixing relay fuse till last night. couldn't source any of that thin copper strip but works sparky says try 30 amp domestic fuse wire. did this,put everything back together and it worked perfectly... once. after that the warning light came on as per dead glow plug i.e. came on for 2 minutes then went off. I took the relay to bits again to ensure fuse was holding, which it was, then tried again and it worked again but only once as before. the plugs are all definitely working so there's no real problem except I'll be selling the car shortly and this type of thing tends to put off potential buyers.
thanks again pod, nick and steve.

 

[Parrot of Doom]

I wonder if the fuses are rated at less than 30 amps, and by putting 30a fuse wire in something has blown on the board?

I have some glowplugs somewhere, I'll see if I can work out what the current flow is normally.

 

[Bolide]

Glowplugs are somewhere between 1.7 and 0.9 Ohms, from memory, so would draw 8 - 19 amps each at 13.5 Volts. The battery voltage will be pulled down by the load so you won't see that much current

If a glowplug is a short-circuit it'll pop a 30 amp fuse with no problem at all. If it's not then it'll be the right resistance or open circuit - I can't see any other options

Based on this, assuming all the glowplugs are within spec and there are no wiring shorts, the problem most likely lies in the relay

Nick Froome
www.w124.co.uk

 

[pivers]

thanks for the tech info guys. I'll just have to leave things as they are for now. at least I don't have the warning light on constantly now.
cheers
pete