Defender 300tdi leaking injectors

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the_wolf

the_wolf

Well-Known Member
Posts
16,791
Location
Stonehouse, Scotland
Wonder if anyone can help me get to the bottom of this. I've had a leak from my injectors and I finally got around to replacing the copper washers. When I removed the injectors 3 of them were covered in sooty diesel whereas 1 was bone dry. I cleaned them up, fitted the new washers and refitted. I'm now just getting a leak from the rear 2 injectors. I can see diesel on the head around the injector studs and clamps. Its definitely not the leak off pipes as those are tight, the pipes are in good condition and the banjo bolts are bone dry. I've tightened the injectors up more than enough yet I can't figure out how I'm still getting a leak. Surely the only way diesel can be getting out that way is a poor seal and with new washers is that even the case? If I sit at idle in my driveway I get nothing and I don't know if it's actually leaking while I'm driving but if I drive somewhere then park up you can see it starting to drip underneath onto the ground. The fact it does that when I stop suggests leak off pipes but as I said that's not the case.
Is there another problem or am I looking at getting my injectors refurbed?
 
My thoughts are seats(might need recutting?) Old sealing washers still in place, can be hard to see them when they are dirty. Or injector body seal has failed, they come apart and it's possible to disturb that joint if the injectors are turned anti clockwise whilst trying to free them.
 
You sure its not the leak off pipe banjo bolt seals that are leaking?

Item 9,
Screen Shot 2021-05-15 at 17.51.47.png
 
I'll double check the leak offs but I'm positive it's not those unless there is a hairline crack somewhere but it seems unlikely given that I'm getting the leak from 2 injectors and not just 1. I'll pull them out again and double check that there's not old washers in there, I did remove all 4 old ones when I took the injectors out so it seems unlikely but wouldn't hurt to rule that out. What do you mean by the body seal of the injectors? It does seem odd that diesel is somehow making its way back up and not only leaking out past the injector but coating the injector too. If soot is mixing with the diesel then that would imply that the injectors aren't fully seated? Or would it?
 
Pic above.
Look at the join in the injector between 6 and 14. The injector screws apart at that joint, don't know what goes there though, suspect a copper washer.
 
Could anyone suggest whether or not it would be a case of just taking the injector up and making sure it's screwed together tightly enough? I can't find much info on taking them apart but a YouTube video showing someone cleaning 300tdi injectors seems to suggest there's no sealing washer between the two halfs
 
the_wolf said:
Could anyone suggest whether or not it would be a case of just taking the injector up and making sure it's screwed together tightly enough? I can't find much info on taking them apart but a YouTube video showing someone cleaning 300tdi injectors seems to suggest there's no sealing washer between the two halfs
Click to expand...

They are normally quite tight, no washer inside.

Are you sure the sealing washers you fitted were copper, there seems to be a lot of copper coated steel washers floating around.

IMG_0544.JPG
 
neilly said:
They are normally quite tight, no washer inside.

Are you sure the sealing washers you fitted were copper, there seems to be a lot of copper coated steel washers floating around.

View attachment 238357
Click to expand...

The only thing I can think of is they're leaking from there, otherwise why would the body of the injector be covered in sooty diesel? The front two injectors are absolutely fine and I replaced all 4 washers with what I'm sure we're the correct copper ones. It's just the two rear injectors that I'm seeing leaking.
As for the injector seat I had the cylinder head completely refurbished about a year or so again so I'm happy that those are fine
 
the_wolf said:
sooty diesel?
Click to expand...
If it is sooty then I do not see how it can be coming out of the injector.

I would pull them and make sure your washers are OK, they are cheap enough to replace with good new ones, check they are not steel, and anneal them if you want to.

Cheers
 
Silly question,

It has been a while since I took a set of injectors off of a 300tdi, but iirc the injector clamps have a bend to them which has to be fitted correctly to apply force to the injector as the bolt is tightened,( Unless I am thinking of a diffent set up.)
Have you checked to make sure you did not make an oopsie when refitting them.

Cheers
 
I wasn't sure, that's where I'm confused. When I take the injectors out again I'll check the washers, I did buy them new as my first thought was the old ones were done. The injector clamps do have a bend in them and I think they are orientated the correct way to push the injectors down when clamped. I had been unable to find anything online about how they should be fitted for some reason.

These are the washers I bought and they are copper https://www.ebay.co.uk/itm/Defender...-/290389182102?_trksid=p2349624.m46890.l49286
 
the_wolf said:
I wasn't sure, that's where I'm confused. When I take the injectors out again I'll check the washers, I did buy them new as my first thought was the old ones were done. The injector clamps do have a bend in them and I think they are orientated the correct way to push the injectors down when clamped. I had been unable to find anything online about how they should be fitted for some reason.

These are the washers I bought and they are copper https://www.ebay.co.uk/itm/Defender...-/290389182102?_trksid=p2349624.m46890.l49286
Click to expand...

When you pull them, put a magnet on them to make sure. If it was something this easy then although a PITA, it would be a simple fix.



Yes if the injector clamp was a U then it would be fitted upside down.

Cheers
 
neilly said:
When you pull them, put a magnet on them to make sure. If it was something this easy then although a PITA, it would be a simple fix.



Yes if the injector clamp was a U then it would be fitted upside down.

Cheers
Click to expand...

That's the way I've got the clamp fitted as that's what made most sense to me. I took a photo of the leak after I pulled into the drive. I kept the engine running this time and checked it. Oddly enough nothing underneath at all, no drips. However you can clearly see diesel around the base of the rearmost injector. When I did turn the engine off that's when it started to drip onto the ground but even with the engine running and with it off the leak off pipes and leak off banjos are totally dry
 

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Don't have a small torque wrench, only a big one but they're tight. The leak off pipes are still in good condition, I replaced the crappy old braided ones with good quality fuel hose.
I removed the injector again and sure enough the body was covered in diesel but the actual tip was bone dry. I did manage to tighten it up a bit so I'm not sure if the thread joining the two half's together had been very slightly loosened. I ran the engine for a while and let it heat up but it didn't show anything although it doesn't normally unless I've actually driven and put it under load.
 
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