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injectors leaking at base (head)
by
knowtwodrugs
on 10 Jul, 2007 11:09
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Hey all, I just put new nozzles and whatnot and cleaned up my injectors while I was replacing my injection pump :? and now a couple are leaking right at the head. Did I just not tighten them enough, or is there supposed to be sealent on the threads or something? Thanks.
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#1
by
Vincent Waldon
on 10 Jul, 2007 14:09
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Did you hand-lap the three essential sealing surfaces on each injector before reassembly ??
I bet I know the answer ??!!!! :wink:
Otherwise:
- proper torque on injector piping ?
- proper torque on injector body ?
- new heat shield ?
- poor return tubing between injectors ?
Vince
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#2
by
knowtwodrugs
on 10 Jul, 2007 16:19
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No I didn't lap them.
I thought you just put them together the way they came apart? I hope I didn't mess anything up too bad doing that.
1 - I don't know how to specify torque with an open-end wrench. I only have a torque wrench that uses sockets. How do you check the torque on the injector piping in that case? I know too much pressure is bad, I only snugged them.
2- No, and I bet that's the problem. My pops is bringing home the torque wrench tonight.
3- yes new heat shields
4- brand new tubing
If the motor fired and ran, am I OK on that lapping thing? Or should I definately remove the injectors and take care of it?
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#3
by
Vincent Waldon
on 10 Jul, 2007 18:49
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Nah, you can't hurt these beasts... well, unless you don't put the timing belt on properly.
Looks like you've got most of your bases covered.
You need to see where they are actually leaking.... I use a can of brake cleaner and my air hose to clean them really really well... then you can see if the fuel is leaking from the very top (the connection with the tubing) or the between the body halves (lapping the components).
Yes you kind have have to guess the torque with an open end wrench... the point is to tighten them enough but not so much that you break the fittings.
You do need to torque the heck out of the body halfs.
As you saw, there are no gaskets inside the injector... rather a reliance on very close tolerances, and as soon as you crack them open to replace the nozzle there's a good chance they won't go back exactly as they came apart... hence the need to hand lap. Do a search here and at vwdieselparts.com and you'll find some good discussions on what and how to lap.
Vince
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#4
by
knowtwodrugs
on 11 Jul, 2007 04:03
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Hmm well I put it all back together and torqued the injectors up to 60. started her up and they're still leaking right at the head. Could it possibly be the result of wear on the head or pistons or something that wasn't a problem with worn out nozzles?
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#5
by
jtanguay
on 11 Jul, 2007 04:27
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by leaking at the head, you mean cylinder head? if you have leaks coming through there, then hmm... bad sealing with the heat shields maybe? weird problem!
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#6
by
knowtwodrugs
on 11 Jul, 2007 04:33
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Yup right at the cylinder head where they screw in. =/
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#7
by
knowtwodrugs
on 11 Jul, 2007 13:33
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It does also release a sort of mist on #4 cylinder. Could that be the boiling of the fuel releasing? I suppose before I take it all apart again I could let it run for a bit and see what happens.
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#8
by
knowtwodrugs
on 12 Jul, 2007 03:28
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No luck on that. My dad's gonna take the injectors to work today and see if anyone has any ideas. He's a mechanic at the turnpike so we will see.
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#9
by
Vincent Waldon
on 12 Jul, 2007 20:59
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Did you hand-lap the three essential sealing surfaces on each injector before reassembly ??
I'm sticking to my story... ;-)
Vince
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#10
by
Black Smokin' Diesel
on 13 Jul, 2007 14:04
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If it's leaking at the head, try to tighten them a bit more. I had the same problem when I replaced mine. I just tightened them more and they stopped leaking.
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#11
by
Black Smokin' Diesel
on 13 Jul, 2007 16:44
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The thing is, there are only two seams that can leak diesel fuel, the seam between the top half of the injector and the center "washer", and the seam between the "washer and the nozzle. The fuel then leaks down inside the bottom half of the injector, past the heat shield and up the threads and out. If you simply tighten the injector to the head, you might be able to stop the appearance of fuel leakage, by tightening the seal between the heat shield and the bottom half of the injector, but the fuel will continue to leak none-the-less. It will fill the space between the nozzle and bottom half of the injector with fuel and gradually carbonize in to an incredibly hard resin. Removal of the nozzle in the future will likely require a hammer. Then again new injectors aren't all that expensive and cores are cheap.
Andrew
Doh
Would that cause white smoke at startup since there's fuel leaking into the cylinder?
Not 100% sure if it was diesel leaking because I used antiseize paste on the injectors before installing them. Maybe it was boiling and coming up making it look like a fuel leak at the head.
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#12
by
Vincent Waldon
on 13 Jul, 2007 18:31
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I think you would get white smoke because you are losing compression to a leak, resulting in poor starting on the cylinder and an incomplete burn.
Like Andrew says, they can only leak diesel at two places... clean 'em with brake cleaner and see which.
If at the fitting, redo the connection looking for cracks in the tubing, dirt, or wrong torque.
If between the injector halves disassemble, lap, and reassemble.
Vince
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#13
by
knowtwodrugs
on 14 Jul, 2007 16:30
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Well we got her running finally! I don't know what he did that I didn't do, maybe he just cleaned the injectors better. Thanks for the tip on the boiling especially, if I hadn't known that I would've freaked. Thanks for all the help everyone.