D5 (D5244T to 2005) Engine won't start after touching injectors pressure pipes

[NB10]

Hey everyone. 2001 S60 2.4 D5 163 bhp here.

Recently decided to change all of my injectors copper washers because I had slight diesel smell in my car and a bit loss of power.



Everything went fine until I tried to remove n°5 injector. Couldn't unscrew the high pressure pipe nut (red circle). It was tightened so hard I bent the pipe trying to loosen it. I quickly stopped as I saw the pipe bending more and more, so I screwed it back, again using all my strength.

Now my engine won't start. Lack of pressure I guess. Diesel is coming out of injector hole when I try to start engine. Also, now there is a slight play between pipe and injector when I move it with my hands (blue circle).

My guess is that I have unscrewed the small nut (yellow circle) when trying to remove the big one. But it won't budge with a classic wrench, I don't have many tools. I just hope I didn't cross-threaded it.

What can I do? Did I break anything, or is it just a matter of screwing back those nuts with appropriate tools?

[Dancake]

If the injector pipe has seized onto the yellow nut, it can twist the pipe causing irreparable damage. The rail to injector pipes are supposed to be single use, so great care is needed when removing them. Flare nut spanners are the best spanners to use when working at injector pipes, though standard open ended spanners can also be used if you're careful to keep them correctly aligned.

In your case I would suggest that you do not try to tighten the yellow circled nut back into the injector. Ideally you need to separate the yellow and red circled nuts without twisting the pipe or allowing the yellow circled nut to rotate at all. If this isn't possible, I would cut the pipe and simply screw out the yellow circled nut entirely, then inspect the threads in the injector and hope they haven't been damaged. Grab a replacement pipe (or set of pipes including the yellow circled nuts from the injectors) from a breakers yard and give them a go, though you may need to remove the pipes from injectors 3,4 & 5 and disconnect them at the rail as well.

New replacement pipes are expensive as you can't buy them per cylinder as such. They come as a set of either 2 or 3 depending on which cylinder you need to replace the pipes on. I have reused many common rail injector pipes without issue, but there is always the possibility that you won't get a proper seal when using second hand pipes. Using the yellow circled nuts from the same car that you get the replacement pipes from will help to reduce the likelihood of leaks after fitting.

Before fitting the pipes, make sure the yellow circled nuts are tight in the injectors. There should be no movement at all here. I suspect looking at your picture that the yellow circled nut has been screwed out a few threads, and is almost free of the injector. This would explain the movement you have described. When tightening up the red circled nuts, don't be tempted to overtighten them when initially fitting. If diesel leaks out when cranking just give them another nip up. Take your time and I'm sure you'll be able to sort it no problem.

[IainG]

Hi
When removing the nut that holds the pipe onto the adaptor it is always good practice to use two spanners. One to hold the adaptor to stop it turning and one on the injector pipe nut. It helps stop this happening. If you put the spanners on close together it is possible just to hold both and squeeze them together to remove the pipe nut without putting any turning force on the adaptor.

Iain

[NB10]

Thank you for your quick replies.

So I unscrewed red nut, I don't know why but this time it came out easily. Then I had access to yellow nut, it was really loose so I screwed it back. Then I put back red nut, and now there's no play anymore, everything is tight and car is starting and rolling fine!!

So I drove it for 30 mins and now I have another minor issue: injector #5 is still leaking a bit, and maybe #4 too. Got strong smell of unburnt diesel and a few fumes. Gotta check this out tomorrow, maybe stronger tightening will solve this issue.

I had another question: torx flange screws are holding the clamp seals, can I replace them with classic M6x40mm bolts? I'd gladly avoid ordering OEM as they're expensive.

[Dancake]

The bolts should not be changed for anything other than OEM, but they shouldn't require changing anyway (unless the heads have been rounded or damaged). Did you fit new injector clamps? If not, did you bend the old clamps so that they exert downwards pressure on the injectors when the bolts are tightened? If you didn't do this, the injectors will not be securely clamped and this will allow blowby on the compression and exhaust strokes.

[NB10]

Originally Posted by Dancake

The bolts should not be changed for anything other than OEM, but they shouldn't require changing anyway (unless the heads have been rounded or damaged). Did you fit new injector clamps? If not, did you bend the old clamps so that they exert downwards pressure on the injectors when the bolts are tightened? If you didn't do this, the injectors will not be securely clamped and this will allow blowby on the compression and exhaust strokes.

No I didn't know about bending old clamps, I will try that. I need to change bolts on #5 because they were rounded by previous owner, I can't get the injector off. I will call a mechanic to do that I don't want to mess things up.

Odd thing is that I didn't touch those bolts but now it's leaking way more than before, yet I tightened the two flare nuts as much as I could. At least my car is running but I have strong diesel smell when engine is hot.

So what could be the risk of using allen bolts of the same size? My volvo is reaching 190 000 miles so I'd like to avoid any "by the book" expenses, if there is another suitable cheaper solution.