300TD Injectors

[Shaun_wells]

Hi All, The good old merc has just failed it's MOT on something I would have never thought off..

I've just been told that injectors on my 93 300TD, are leaking.

The question I would like to ask is ?

Can I replace the injectors myself, is it a matter of removing and replacing the old injectors with newer ones.

Any idea on how much an injector costs ??

All advice welcomed..

Thanks.

 

[jibcl500]

Injectors dont leak unless cracked, the seals at the base of the injector fail, easy enough to do, new seals, and stretch bolts but if the top of the engine is covered in back tar that needs to be cleaned before hand.


jib

 

[rpe2]

Hi All, The good old merc has just failed it's MOT on something I would have never thought off..

I've just been told that injectors on my 93 300TD, are leaking.

The question I would like to ask is ?

Can I replace the injectors myself, is it a matter of removing and replacing the old injectors with newer ones.

Any idea on how much an injector costs ??

All advice welcomed..

Thanks.

If it is a non CDI engine then the injectors screw in. I would guess that any residue is from the supply/ return pipes leaking. Can't see why this on its own is a MOT fail.

 

[Number_Cruncher]

A fuel leak where the MOT inspector can actually see fuel leaking will and should attract a fail.

Is this an OM603?

It's important to find the *exact* source of the leak;

it could be the leak off pipes (very common), and this would cost a few pounds and half an hour's time to fix.

it could be a failed / cracked injector body, which is much rarer, and more expensive

it could be a failure near the union of the high pressure metal injector pipe - these are about £30 each, and failure is quite common, but very common if the injector pipe clamps have been damaged or left off - the pipes vibrate and fail via fatigue.

To find the exact source of the leak, dry the area off with something like carb cleaner, and then run while watching.

It's definitely worth changing the leak-off pipes as a matter of course if they haven't been changed in the last year or two. The pipes become brittle with age, and can become quite troublesome.

 

[Shaun_wells]

This is very helpful, thanks for your reply.. I will investigate further.

 

[Shaun_wells]

Do you have a diagram to explain the below..

'It could be a failure near the union of the high pressure metal injector pipe'

Also do the injectors screw in or are they pulled out ?

Sounds to me if I have a seal problem, as I have a build up of black tar round the injectors.. Which has been there for a good year or two, so they could have failed now.. Injectors 3 and 4 if the numbering is from front to back don't have so much of a build up. Might as well replace all seals..

Cheers..

 

[Number_Cruncher]

If you're not sure where the leak is, first, clean the area off with some solvent or engine cleaner.

Wherever your problem is, replace the leak off pipes as a matter of course - these are the flexible pipes which go from injector to injector, and from No 1 injector to the fuel filter area. The rearmost injector has a stopper, or bung in its un-used leak off port; replace that too.

Leak off pipes cost a few pounds to replace, are almost always brittle and leaky if they have been in place more than a year or two, and simply aren't worth spending any significant time on - replacing them all shouldn't take much over half an hour, and shouldn't cost much over £10 - £15 for the new pipe.

The high pressure fuel injector pipe is metal, and fastens into the top of the injectors with a nut - the pipes can fail close to this nut, and leak lots of fuel out. If you engine isn't awash with fuel, it's unlikely that this is your problem.

Unless you KNOW that you need to take an injector out, leave them in place. It's unusual for the leak to be the injector itself.

 

[Parrot of Doom]

My engine has a minor issue where oil vapours sometimes collect at the back of the engine, at the rearmost injector, forming a puddle of 'oily stuff'. Not diesel. Worth checking.

 

[Shaun_wells]

I've eventually got round to cleaning up my injectors and then revving the engine to see what happens.. I can clearly see a drop of fuel now and again leak coming from injector1 pipe but nothing from injector 2 as stated in the MOT failure notice..

So I will replace all the flexible pipes between each injector.

Just phoned my local GSF car parts.. £2 for a metre of pipe.. So that pretty cheap.. Will get this done at the weekend..

Last question, when I remove these pipes.. Will I end with loads of fuel ****ing everywhere continuosly...Or will it just be what's left in the pipe ?

 

[Number_Cruncher]

>>Will I end with loads of fuel ****ing everywhere continuosly.

No - a mere dribble!

 

[Parrot of Doom]

IIRC you need 1.1 metres.