Oil leaking from injector housing.. bad news??

discomania · May 8, 2018

LeftFoot said:
Two things I have noticed recently:
1. Starting on mornings (cold start) usually takes 2 attempts at swinging. Fires up on the second attempt each and every time. Compression issue?

The starting issue could be your leak-off pipes leaking diesel which means the system is needing to bleed a bit on start, which is your diesel leak. Go and inspect very carefully the leak off pipes, a hard pipe will also cause leaks as it will not seal well on the barb.

Rougharse Racing · May 8, 2018

That black gunge is not oil, it is blow-by from a leaking injector seal. (A mixture of soot, diesel and combustion sh1te.) If it has been leaking for a while the sealing face may be damaged by heat and need re-cutting for a replacement seal to seal properly.
You can get hand tools to re-cut the injector housing, or your local garage should be able to help you out.

LeftFoot · May 9, 2018

discomania said:
I doubt that is oil coming up past an injector as there should not be any quantity oil down there! Maybe sooty diesel but that would be chuffing and blowing out spraying sooty diesel everywhere.

However, looking at those leaks I expect it might be the rocker cover seal - often is. They can be a pig to get to seal properly due to the bad 3 bolt design - the way the seal works and the low torque value (10Nm) allows the seal to sit up, then you torque it down and as you go along doing it in stages and in sequence it will pull one side down to 10Nm, the rocker cover then rides up a fraction on the other side, the next bolt then gives a false reading of torque because the cover has see-sawed and you also have some friction on the bolt etc. etc. It's a pig. Even taking your care and applying all the engineering tricks in the book as used on flanges and cover plates and all sorts... they still tend to leak a bit. Also, the covers can warp - I had one that would not seal - took it off and checked the sealing face for flat it was like a banana!

I will have to take a closer look at the cover to see if it is indeed at fault. You are correct in pointing out that they can be a pain to get tightened down square and evenly.

LeftFoot · May 9, 2018

Rougharse Racing said:
That black gunge is not oil, it is blow-by from a leaking injector seal. (A mixture of soot, diesel and combustion sh1te.) If it has been leaking for a while the sealing face may be damaged by heat and need re-cutting for a replacement seal to seal properly.
You can get hand tools to re-cut the injector housing, or your local garage should be able to help you out.

Been leaking for about 4-5 weeks. Might have been there before but it became very noticeable after I re-installed the injectors after getting them cleaned and pressure tested. Perhaps I damaged the face whilst trying to remove cold copper washers with a screwdriver.
Re-cutting the housing/port as you advised above, that sounds like a head off job. Is it?

Rougharse Racing · May 9, 2018

No, you just whip the injector out, re-cut the face and put it back together. If you get a leak, the hot gasses can put a small ridge on the face as they leak past, which prevents the new seal doing its job. The tool for the job is a hand tool and you only clean up the surface rather than taking masses of metal off.

discomania · May 9, 2018

LeftFoot said:
Been leaking for about 4-5 weeks. Might have been there before but it became very noticeable after I re-installed the injectors after getting them cleaned and pressure tested. Perhaps I damaged the face whilst trying to remove cold copper washers with a screwdriver.
Re-cutting the housing/port as you advised above, that sounds like a head off job. Is it?

Before you do anything like this, start with the simplest things, as listed by others and myself above, first. Don't even touch the injector until you are 100% sure that is where the issue lies.
I'd be looking at this sluggish first start and oily mess in conjunction with each other just now - so assume diesel leak and go from there.

Can you hear any chuffing or bubbling or see any spitting from down the side of the injector? Get some soapy water or leak detection spray onto it, test it cold and when hot, look for bubbles developing.

LeftFoot · May 9, 2018

discomania said:
Before you do anything like this, start with the simplest things, as listed by others and myself above, first.

Agreed. Simple things first.

discomania said:
Can you hear any chuffing or bubbling or see any spitting from down the side of the injector? Get some soapy water or leak detection spray onto it, test it cold and when hot, look for bubbles developing.

No chuffing heard but the soapy water test did cross my mind. I will report back with my findings. Thanks.

Oil leaking from injector housing.. bad news??

discomania

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Rougharse Racing

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LeftFoot

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LeftFoot

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Rougharse Racing

Well-Known Member

discomania

Well-Known Member

LeftFoot

Active Member

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