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Discussion Starter · #1 ·
Hi All,

So I finally replaced the valve cover gasket along with the injectors seals that where leaking diesel onto the valve cover. I took it for a test drive and its smoking down from by the DPF, exactly the same as before, but as I never had any engine degreaser I didn't clean up the oil from before so I think (hope) it's just the residual oil, but how long should I expect it to continue for before taking another look just on the off chance there's another reason for it.

Here's a video of the valve cover removed and the oil residue from what appeared to have started from the back corner of the valve cover onto the manifold and further down.


Here's some photos







And here's how it's smoking after replacing the valve cover



 

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Wow, that's a lot of smoke. Does that occur immediately after start, or only after getting warmed up? If that is occurring immediately after start on a cold engine then of course it is not from the valve cover leak at all.

With that much smoke, I would be suspicious of a leak from the exhaust manifold, or a disconnected/burned through line connected to your dpf or exhaust manifold, or a loose connection to your dpf. There are 2 dpf pressure sensor lines that go from the dpf up to a dpf pressure sensor located near the vacuum reservoir, they are known to slip off the dpf sensor on occasion. Also there is an exhaust gas pressure line that has a rubber section in it that is known to burn through. See post #9 in this link.

With that much smoke, I am very suspicious of an issue with your exhaust manifold. I could be wrong but the bolt on the rear top exhaust manifold stud doesn't look like it's torqued down tight. Granted, I don't think you would get nearly that much smoke from one loose manifold stud bolt, but if one (or nore) of the lower manifold studs are snapped off or loose that could be the source.

I am in the middle of a another forum discussion about a leaking exhaust manifold - you can read about it here. I realize by thinking exhaust manifold that I sound like the guy with a hammer and now everything looks like a nail, but I'm suspicious. As noted in the link above, it is a moderately common issue. Any whining noise when revving the engine over 2200K rpm?

Hope that helps, I also hope I'm not like Chicken Little that the sky is falling. If the smoking goes away in a few days, or if there is no smoke until after the engine is warmed up, then disregard all of the above!
 

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Discussion Starter · #3 · (Edited)
Hi Stevie,

No mate, there's no smoke until I take it for a drive. When I test drive it today we was looking for a good 5 / 10 mins but the smoke seemed to die a tad so I took if for another run and when I got back same thing. Also, I don't have a DPF on my E90 and my gosh the things absolutely pongs, so if this was exhaust fumes pre-dpf I have a feeling I would tell straight away as I'm fairly familiar with that pongy smell lol.

I'm avoiding driving it at the moment as it has no service history and the air filter is in a sorry state so my plan was to get it serviced and then Ill have the oil on "max" level on dipstick (it's about midway at the moment) and that way I can see if there's any loss of oil, if not it may confirm more that this is just residual oil that is burning off. I hope it is, I've had the car few about a month, drove it once and its been on Axle stands up till today. Its coming along nice, new handbrake actuator, replaced throttle body from my E90 so no shudder (and no issues with dpf regeneration) then injectors and valve cover gasket, handbrake shoes.. Its just been a looooong journey so far haha. Still got the transmission service to do yet but engine service, tyres and alignment needs to be done first.

Update:

It's not concrete to go on, but I counted and from the three threads I can see on the exhaust manifold on the picture and they all have 7 threads after the nut, so it would be a bit strange for that one section of manifold to be black and the rest fine.
 

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Great idea about counting the threads! So then never mind! Hopefully it will sort itself after a few hours of driving.

Good luck with the rest of the maintenance/repairs, and let us know what happens with the smoke over time.

Regards.
 

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Discussion Starter · #5 ·
Great idea about counting the threads! So then never mind! Hopefully it will sort itself after a few hours of driving.

Good luck with the rest of the maintenance/repairs, and let us know what happens with the smoke over time.

Regards.
Will do Stevie! Thanks very much for your detailed initial reply with the links it's much appreciated. I'll keep you updated when I'm actually driving the car, I NEED to see the fuel economy improvement to lower my anxiety, I put £30 in, drove home and after 22 miles I got the "reserve fuel" light.. Its about the only occasion you could see diesel pooling on the valve cover and say "thank the lord" :LOL:
 

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Wait, what? Diesel pooling on the valve cover gasket? I assume leaking from the return lines? Have you checked the o-rings on those? Could the diesel be dripping down onto the exhaust and causing the smoke?

Or am I mis-understanding and was this leaking diesel from before the valve covert gasket repair, and there is no leaking now?
 

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Discussion Starter · #7 ·
Wait, what? Diesel pooling on the valve cover gasket? I assume leaking from the return lines? Have you checked the o-rings on those? Could the diesel be dripping down onto the exhaust and causing the smoke?

Or am I mis-understanding and was this leaking diesel from before the valve covert gasket repair, and there is no leaking now?
It was indeed mate, here's the pool


This was prior to the valve cover replacement of course.

I couldn't see if it was the injector leaking or the return line so amongst many other things that I ordered I got some copper O-Rings for the bottom, the injector body o-ring and the tiny return line o-ring to cover all bassis, if the return line itself was split or injector nipple cracked I was going to take them from my E90.

After my drive I checked the valve cover and so far I can't see anything so I think it's sorted. I'm sure injector 5's body was filthy as well, so it appeared that the body o-ring may have failed.
 

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Discussion Starter · #8 ·
Right, the diesel leak is sorted. Took it out for a drive and fine, then took it on a dual carriageway, came back and seen this


Legit confused now, valve cover has been done and from what I can see with the endoscope it's absolutely fine (from the areas I can inspect anyway)

There does appear to be oil around the head gasket, I do believe this is common to see after having a failed valve cover gasket as the head gasket has a lip.. But yeah because of the tiny amount of space I have and the heat in that area I'm struggling to source where exactly its coming from.


 
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