Diesel fuel leak rear engine. Not injectors or head gasket

[Timelourd]

Hi there. Help me find my fuel leak? I just replaced the injectors and the head gasket, and used new bolts on the head gasket. Top of the engine, including the fuel injector pump are all dry, but underneath, every time I stop, there's a new funtime puddle of diesel rainbows polluting every driveway or parking lot we stop in. I've checked all around the head - it's all dry, including the rocker cover.

The bottom sort of pan-like structure underneath, which covers the union between the engine block and transmission, is soaked in diesel though. At least, I think it's diesel - it doesn't have a very strong diesel smell though. It's clear, though, so it can't be motor oil as that just turns black as soon as it goes in.

It's getting frustrating, because I haven't delved into the underside of the engine, or the seal between the engine and the transmission. I'm hoping that's not it, because I'm assuming that requires an engine lift.

So, if it isn't the injectors, the fuel pump, or the head or the rocker covers (all new), then what are the remaining culprits?

I know enough to have changed the head and all peripheries, but not enough to know the transmission and underside of the engine.

Any help would be appreciated. I'll be going a deep dive under the van next week, so would be great to get a couple ideas.

[dumper]

Have a look at the injector leak off pipe where it goes round the back of the engine I can’t remember if it goes to the return line to tank filter head or pump

[twin wheel camper]

Have a look at the injector leak off pipe where it goes round the back of the engine I can’t remember if it goes to the return line to tank filter head or pump

It goes to the return line, that’s where I would think your leak is coming from
Work your way back from the injector leak pipe(it’s a small rubber pipe 3-4mm (inside) approximately coming from either the front or back injector) and running to the return diesel pipe at the very back of the engine just up above the gearbox, it t,s into the return pipe and is probably split and leaking diesel at the joint.
If the leak off pipes are looking even a little iffy you should just change them they only cost £5-£6 for a meter length of pipe.

[gotgcoalman]

Just a silly idea.
When you did the head gasket you didn't trap the fuel return pipe and put a hole in it?

[Timelourd]

Have a look at the injector leak off pipe where it goes round the back of the engine I can’t remember if it goes to the return line to tank filter head or pump

It goes to the return line, that’s where I would think your leak is coming from
Work your way back from the injector leak pipe(it’s a small rubber pipe 3-4mm (inside) approximately coming from either the front or back injector) and running to the return diesel pipe at the very back of the engine just up above the gearbox, it t,s into the return pipe and is probably split and leaking diesel at the joint.
If the leak off pipes are looking even a little iffy you should just change them they only cost £5-£6 for a meter length of pipe.

I'll have a look. Fingers crossed it's this, guys. Thanks for the idea. The return from the rear injector>fuel line> fuel filter looks fine, but I haven't checked the return to tank.

I'll update later.

[Timelourd]

Just a silly idea.
When you did the head gasket you didn't trap the fuel return pipe and put a hole in it?

The back of the head was pretty clear when I mounted, so I doubt it, but it's not impossible, and I'll check.

[Keef]

Might also be worth checking the lift pump and push fit fuel line connectors?

[Timelourd]

Still unable to locate the source of the leak. Checked back of head, fuel lines and they're all dry.

It's puddling just underneath the injector pump, but that's dry all over. Pipes are all secure with no leakage. I can't fathom where this leak is coming from. The only thing that isn't solid steel is a big, fat bolt on the engine block. (That's somewhat visible as a dark blotch in the most zoomed in picture.)

I have taken pictures of fuel leak locations.

Further notes:
- The fluid in question smells like diesel, but it's not extremely pungent. I'm assuming that's due to the relatively small amount of it. But, it is oily, and still smells like diesel, though faint.
- The clutch cable just snapped today. The clutch engagement arm that the cable attaches to under the vehicle is somewhat free, so I should be able to replace it and drive, but it has been sticking in 1st and 2nd rather badly lately. I'm including this just in case it's relevant.

[Chug]

When I've had tricky to find leaks I power wash it all down and then when dry wrap paper towels around the injection pump and injectors, filter, etc, run the engine for a minute at a time and keep checking the paper towels for signs of dampness.

[Tpaynter]

Still unable to locate the source of the leak. Checked back of head, fuel lines and they're all dry.

It's puddling just underneath the injector pump, but that's dry all over. Pipes are all secure with no leakage. I can't fathom where this leak is coming from. The only thing that isn't solid steel is a big, fat bolt on the engine block. (That's somewhat visible as a dark blotch in the most zoomed in picture.)

I have taken pictures of fuel leak locations.

Further notes:
- The fluid in question smells like diesel, but it's not extremely pungent. I'm assuming that's due to the relatively small amount of it. But, it is oily, and still smells like diesel, though faint.
- The clutch cable just snapped today. The clutch engagement arm that the cable attaches to under the vehicle is somewhat free, so I should be able to replace it and drive, but it has been sticking in 1st and 2nd rather badly lately. I'm including this just in case it's relevant.

I have the same leak!! Any update? X


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[dumper]

Not on a transit but on a Bosch pump on a Cummins engine it’s been a coming from a injector pipe with a weep so small that it takes time to build up under pressure if you slacken the pipes off on the pump and retighten them it may re seat them and seal them if that’s the problem we used to get this a lot when changing pumps and it worked but sometimes it needed a new pipe.the throttle spindle was another point that’s possible

[cherniy_chack]

This could be a coolant leak.
It tastes sweet.
I liked the idea of cleaning the engine dry from the traces of leakage and, after starting the engine, use paper towels to find the place of the leak.

[V184]

side plate/ 0 ring

[Timelourd]

Hey guys - an update years later.

Turns out it was, in fact, my front injector leaking. I had replaced it on the beach in Spain, but I must have bumped it during install and it had somehow been leaking the whole trip across europe.

Brought it into a Scottish garage when I got home, and when the MOT was halted, I asked the guy what he thought the leak came from, and he looked at it for about 2 seconds, shrugged, and said, 'Might be the front injector.'

I ordered yet another injector, installed it... and... wait for it...

no leak.

So yeah. Just recording this for posterity.