leaking injector nut

[johnf]

I have just returned from a weekend on boat and noticed whilst motoring a small amount of diesel coming out around nut holding one of injectors in engine. it was probably about a teaspoon an hour and seemed pretty steady for the 10 hours motoring we did. I was tempted to give it a slight tightening, perhaps a quarter turn but did not for fear of damaging something inside injector, perhaps there is a washer failing and I could have made it worse??? We are due a big family holiday for 3 weeks next month and will probably do about 50 hours motoring in med, any advice welcome should I just to leave alone for now and dab off diesel as I did or tighten or get a mechanic to look at it. The engine is a 15 year old mercedes omc 636.

 

[sailorman]

I have just returned from a weekend on boat and noticed whilst motoring a small amount of diesel coming out around nut holding one of injectors in engine. it was probably about a teaspoon an hour and seemed pretty steady for the 10 hours motoring we did. I was tempted to give it a slight tightening, perhaps a quarter turn but did not for fear of damaging something inside injector, perhaps there is a washer failing and I could have made it worse??? We are due a big family holiday for 3 weeks next month and will probably do about 50 hours motoring in med, any advice welcome should I just to leave alone for now and dab off diesel as I did or tighten or get a mechanic to look at it. The engine is a 15 year old mercedes omc 636.

just "Nip it up " should do the trick

 

[vyv_cox]

Any mechanic you paid to look at it would do as Sailorman suggests as a first step. The question from your point of view is how much does nipping it up a bit constitute, and what happens if you nip it up a lot?

The worst you could do is strip the threads but you have to be pretty powerful to do that. I suggest you use a short spanner, 8 inches maximum, and tighten it firmly. Nowhere near the level of veins popping out in your neck, just a firm pull. That will almost certainly be enough, all you are doing is pressing two cones together to re-seal them.

If this isn't successful you may need to consider going further and having someone look at it. Don't be tempted to use any sealant.

 

[sailorman]

Any mechanic you paid to look at it would do as Sailorman suggests as a first step. The question from your point of view is how much does nipping it up a bit constitute, and what happens if you nip it up a lot?

The worst you could do is strip the threads but you have to be pretty powerful to do that. I suggest you use a short spanner, 8 inches maximum, and tighten it firmly. Nowhere near the level of veins popping out in your neck, just a firm pull. That will almost certainly be enough, all you are doing is pressing two cones together to re-seal them.

If this isn't successful you may need to consider going further and having someone look at it. Don't be tempted to use any sealant.

check the rest whilst you under the bonnet as well

 

[oldharry]

Agree with Vyv Cox, you wont do any harm unless you get a huge spanner and a gorilla to heave it. If you cant seal it, then take it off to see if gthe flanges are damaged. if so either a new pipe, or having the flare remade by a garage should solve it, unless the actual injector body is damaged, which is unlikely.

Thats assuming it is the nut on the injector high pressure pipe that is leaking. Some engines have a banjo type bolt usually on top of the injector for the return pipe, this is hollow, and should be treated with more respect as it can shear if seriously overtightened. Banjo bolts have either copper or fibre washers, which can easily be replaced if they leak. They are supposed to be replaced every time they are opened, but often they are not. Other return pipes are plastic and can split at the joint, causing a leak. Replacement is the only option here.

 

[misterg]

... whilst motoring a small amount of diesel coming out around nut holding one of injectors in engine....

I'm not clear where you mean.

Does your engine look anything like this?

If so, are you seeing the leak at 1, 2 or 3 (on whichever injector) or elsewhere?

One further possibility to be aware of is a corroded/cracked injector pipe that's just beginning to leak. If it's not just a weeping joint, then try using a powerful light to check for diesel mist while the engine is running - don't use your fingers!

Andy

 

[pappaecho]

I think I would run the engine and watch the leaking nut under bright light to see the weep. I would nip up with a fraction of a turn and see what happens

 

[johnf]

Hi Misterg

Engine looks similar to photo and is leaking at point 1. Thanks for help

john

 

[VicS]

is leaking at point 1.

The pipe union on top of the injector then.

Just nip, no more.

 

[misterg]

^^^ What he said.

Andy