Turbo oil lines on the diesel

[Diesel Spectre]

Sooooo.....
When I picked up my e70 the engine compartment was super clean for 116k miles. Last oil change I noticed a little “sticky dirt” over by the turbos. I had the hood up trying to figure out why I’m getting a rough start all of a sudden (probably the glow plug module since I’m getting LIN bus codes). And holy crap, everything on that side of the engine is covered with oil. It’s not spraying from anywhere but I am getting oil spots on the driveway. I started digging around and pulling things apart (had to do the front egr cooler anyway) and what I found surprised me. My valve cover gasket (the first suspect) appears to be in good shape. I started looking more closely and found the turbo oil lines are saturated. It looks like the flexible portion of the lines has lost integrity due to heat cycling and the oil is just weeping through and covering everything else. Hopefully that’s the only culprit.
So has anyone done this job? Dealer say it books 13 hours to do, so after I un-puckered and muttered a polite “no thank you”, I resolved to do the job myself.
I couldn’t find any diy or videos and that 13 hour book time makes me think I’ll have to drop the whole engine. Looking for advice or pointers, really any direction at all.
Anyone diy their own lines for this?

[smassey321]

Most of the hoses are easy to replace. But there is 1 bolt that is blocked by the turbo which is where all the hours come from.

https://www.e90post.com/forums/showthread.php?t=1346704
https://www.e90post.com/forums/showthread.php?t=989221

[Diesel Spectre]

Good links, thank you. I guess I need to buy an e90 so I can join that forum. (The wife may buy that ��). I’m gonna have to just jump in and do it. I’m planning to pull the line and take them to the hydraulic shop to have them “reproduced”. Trying to figure out ways to eliminate potential problems down the road. The back story is that my mk4 vw Gti had a problematic turbo coolant line (APR 3+ turbo) and I fought with it for years. I went through several types that were all stainless braided and I finally solve the problem by making the whole bottom half of the line out of stainless tube. Had it bent and silver soldered (brazed) the banjo fitting on. No more worries.
That said, this Isn’t the same kind of car as a modded, big (for the application) turbo, double the factory hp is, so I’m not going crazy to “mod” anything. This is my daily and I love it the way it is. Think OEM +. Just upgraded for reliability and stoutness. If I make these lines right, I may be able to put a disconnect between the hard line and the “flex section “ so the only thing that will fail will be accessible without pulling the large turbo again. It does create additional connections (read; failure points), so I’m still undecided.
Any additional comments are appreciated as that will help me refine the plan.

[robinasu]

I'm surprised there is not a hard line kit available for these oil lines- maybe not possible?

Regarding the hardest connection, maybe you can cut the banjo bolt off and unthread the tip in the available space, then install a right angle fitting? I have never worked on the oil lines so sorry if this is a dumb idea.

[Diesel Spectre]

If it works, it’s never dumb. It would be nice to do all hard lines but I’m concerned about 2 things.
1) the stresses from vibrations and heat expansion.
2) there Is no phenolic break between each banjo fitting so the entire thing from turbo to turbo to block will transfer heat, both end to end and through to the oil over the whole run. My concern is that the oil in my feed lines will be more likely to coke and block the line/s.
Maybe I could do all in hard line with a short break in the middle. I can connect the hard ends with a short piece of Teflon flex to allow the system to deal with the stresses of vibration and heat expansion. Maybe I could dig up some fire sleeve (silicone coated insulation) to help with the heat transfer to the oil. I worry that the fire sleeve will (once heat soaked) actually trap heat in instead of out, making the coking potentially worse.
Thoughts on insulating hard lines at least right next to the turbo & DPF? Maybe a heat sink for the lines is a better plan?

[robinasu]

The new oil lines have that aluminum heat shielding for radiation to protect the rubber. Should be ok. What could go wrong?

Conduction is a good point. I would think the oil would cool the lines but I'd need to think about it more. The oil cooler can only cool to the engine coolant temp of ~88C (remind me if it's oil to water or oil to air- I forget). I would think the turbos are right after the cooler, or close to it. From what I have seen in the way of racing cooler lines: they are hard with a short section of hose- unclear if that is for installation or vibration. I don't think a full hard line would have vibration problems if each end was secured. This seems like something done on all types of machinery. I think the full hard lines are harder to install on the line and would need to be pretty precise during manufacturing.

I made a hard line for a special brake booster application and it was hard to get it right. I can see why manufacturers use the hosed versions.

[Diesel Spectre]

Yes, the oil will cool the lines and that means the lines are heating the oil flowing through. Not good. Newtis (in turbocharger faults) states explicitly, many times, that with any turbo replacement the supply lines should be replaced and return line thoroughly cleaned. Upon turbo fault, the lines are the first suspect. That’s clear direction to the dealer network to mitigate burning up new turbos at dealer & BMW expense. If that’s not a sign of “CYA”, I’ll crap a bigger turbo.
All this adds up to room for improvement. I’ve gotta do them (well, 1 of them) so I might as well give it a shot.
To insulate or not? Another method for heat? Extra joints in each line to make them serviceable, or no extra joints to eliminate potential failure points?

[Diesel Spectre]

Most of the links I have found about that large turbo feed line indicate the turbo must be loosened, but not removed. Are the actual sealing surfaces loosened and gaskets just re-used or are they just pulling mount bolts to get a little extra room? How much can you really flex the exhaust manifold to turbo connection? Re-using those gaskets sounds like a recipe for sealing issues down the road.

[Diesel Spectre]

Side bar; did that glow plug control module today... tried to use the “easy method” probably would have been faster to pull the intake and do it. It’s up a lot higher than the sedans for which this method is used, making it almost impossible to bend your arm down and get enough leverage and strength to squeeze that rear release on the large connector. It took an hour. Maybe I’m just out of practice since I haven’t had any bad experiences working on it yet. I was having flashbacks of doing the alternator on a 2.7tt audi allroad. CEL is gone and all is good. That method does work for us E70 folks but expect to curse a lot and run out of patience before it’s over.

[robinasu]

One way to look at it is: how much heat is added to the oil and removed from the oil line in the time the oil moves from one banjo to the other. There will be a rise (or fall) in temperature before it enters the turbos, but not much. Seems like it would be background noise levels. You could put a thermocouple on each end to get an idea with the current hose. Being outside the engine it might even cool a little. I think it would be small amounts of heat, but you gotta do you.