N63 turbo coolant hoses leaking,,,,when they start to leak they leak onto a 3 way by-pass hose,,,,when the coolant gets on the 3 way hose,,,,the 3way is plastic and the plastic gets brittle and cracks and leaks,,,,,causing a lot of problem,,,,,some time the turbo coolant pump runs dry,,,,causing it to fail,,,,,this is a very bad design,,,,,but what isn’t on the N63,,,,,,you can do this repair at home,,,,no need to lift the car up,,,,,everything done on top,,,,you will have to loosen the turbos to replace the turbo coolant lines.
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bmwtechnician 
do you have to part number for the hose and 3 way connection?
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I’m sorry I don’t have the part number for the 3 way by pass hose
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part number 17127576363
See here for more info:
http://f10.5post.com/forums/showthread.php?p=20232122#post20232122
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Yes that’s looks to be the part number,,,,,make sure you get new hose clamps
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Could I use a brass T fitting in place of the plastic Y fitting?
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You could,,,,but all the work and struggle to remove that Y hose and replace the T fitting with a brass one,,,then put the whole hose back in is a waste of time,,,,,just replace it with a new hose,,,,,besides I have seen these hoses leak at the ends ,,,,,,due to the heat from the turbos,,,,if you replace that hose,,,,disconnect the battery please,,,,the alternator has 12v and I have seen screw drives and tools touch it and spark.
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What are the hose diameter size?
What is the Y fitting size?
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I don’t know what size they are.
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How does this “Y” cause to turbo pump to fail when the pump is on a separate cooling system.?
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The turbo coolant pump is linked into the Y hose
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I’ve managed to remove passenger side hose completely. I still have problem with the driver’s side. I’ve managed to unscrew the clamp (not completely, till the point when it moves somewhat freely) and i can’t seem to take the hose off. Do you know any tricks for that? I’ve tried cutting it’s side (the one that i have access to) to release tension around the nipple, but with no success.
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You have the right idea,,,,or try a long thin flat screwdriver and try and peel the hose off where you cut it,,,,with the screwdriver you sometime can cut the hose,,,,just take your time and be patient is everything when doing that job,,,,good luck
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I pulled the Alternator and was able to change quickly with no problems.
The leak caused my alternator voltage regulator to fail – thus I was able to change out the VR during this time. No problems.
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Glad to hear everything worked out for you.
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I’ve recently flushed coolant in my F10 550i and I’m still wondering how do I let all the air remaining inside the cooling system out. I initially let the car idle (+max heating) for about 15mins with the coolant reservoir cap off, but I haven’t seen any bubbles escaping inside the reservoir. Recently, I’ve noticed coolant smell under my hood after driving (Y-hose and turbo coolant hoses are ok, I’ve replaced them recently; thank you for help 🙂 ). I’ve tried driving without the heating on and it seems to help a bit. I assume that there is still some air left inside the system and that the coolant is being pushed out of some sort of vent. I have also noticed that the coolant level inside the reservoir dropped ~1/4inch.
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Problem solved, I have missed one of your recent blog posts. I still have one extra question: the reservoir cap has to stay on throughout the entire process, right? If so, how is it possible for air to come out of the system if the cap stays on the entire time?
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The cap should be off while bleeding the coolant when the car is standing still,,,,but when you go on a test drive the cap should be on good and tight.
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Those are pretty easy to bleed due to the belt driven water pump,,,,while the engine is idling,,,you should have some coolant pissing into the expansion tank,,,you can rev the engine up to 2500rpm and see if that helps piss the coolant into the expansion tank,,,,,also did you make sure the small coolant resvoir for the turbos has coolant
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Thank you!
Yes, I do have coolant in the turbo reservoir. These two coolant circuits are independent, right? The main one is belt-driven (+some auxiliary electric pumps) while the turbo/charge circuit is driven entirely by electric pumps, right? I can see that turbo coolant is kinda dirty compared to main circuit one (recently replaced). I’m planning on replacing turbo coolant as well. Is there any drain plug for this circuit? I assume that since turbo coolant is pumped by electric pumps, after replacing it I have to run normal bleeding procedure (battery charger, ignition on, heating max, low fan speed, doors shut, gas pedal for 15s).
Once again thank you for answering and running this great blog! Happy New Year!
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Ok they are two circuits,,,,,but and I mean but the turbo circuit does bleed into the main circuit,,,,if the turbo circuit needs coolant it can get it from the main circuit,,,,I know it’s crazy and doesn’t make sense ,,,,lol,,,,now when you do work on the turbo coolant circuit,,,,,yes that is a electric coolant pump and yes you have to step on the gas pedal to bleed.
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There are no block drains on my N63. Also note the coolant cover on the rear of mine was leaking at 67K miles.
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Rear coolant cover above the rear main seal.
11 14 7 567 643
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Yes I know what your talking about,,,,they have been known to leak.
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Yea I don’t think there are any block drains on a N63 that I remember .
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When is fitting starts to fail and get brittle, does it have a weird plastic / oil burning smell to it?
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No they don’t have a wired smell,,,,,could it be possible that a plastic bag got stuck on the exhaust while you were driving,,,,and the plastic bag is melted on the exhaust.
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I’ve checked underneath.. Nada. Now this is all stemming from me bringing my car into the dealership smelling an oil leak. They said it was the valve covers. Had them replaced ($2500). I could still smell it. Brought it back. They said it was a bad cleanup job from the valve cover casket replacement. Said it should be fine now. I just brought it in again (2 weeks later) because I’m STILL smelling oil burning. No leaks on the ground. The dealer said valve cover is NOT leaking, and suggested I need valve seals. As if that’s what I’m smelling. I can literally put my nose up to my grill and to the top of my engine and right when I open the driver’s door… I can smell it. This coolant tube was leaking a tiny bit, but it was right at the clamp and I just tightened it…. Going out of my mind here. BTW, rear main was replaced recently. It’s had the CCP done.
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There is a oil plate under both turbos,,,the plate is where the oil return from the turbos goes though,,,,this oil plate starts to leak,,,,and the leak starts to puddle under both turbos,,,,the oil will start to exit out the front or rear of the engine block,,,,I hope this helps
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OK. I’ll try to check that. Do I have to do a lot of removing to see it?
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You can remove the upper engine cover,,,and look between the two turbos and see if there’s any oil or coolant
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2011 550i, had CCP done. White smoke out tailpipes (valve seals?) and coolant leaking from underneath (already had these three lines replaced). Where else could coolant be coming from for the leak to only show under the car? Thanks!
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I don’t know where the coolant leak is coming from,,,,can you see any coolant inside the engine compartment,,,,did you check the expansion tank sometimes they crack.
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The block has a tiny drain hole for anything that leaks on top of the engine to drain out the rear of the block. Mine was plugged so nothing could leak through. When the rear coolant plate leaks on the back of the cylinder block the puddle will be directly under the split of the bell housing right by the rubber plugs that cover the bolt holes.
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There must have been a big puddle
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Any idea what side this tiny drain hole is located?
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It’s in the center,,,hopefully you saw the picture from one of the post
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The puddle was very small overnight with the cooling system pressurized. Matt the valley drain is about 6 mm through the block then through the rear coolant plate. Here’s a picture of the crud coming through the drain hole.
http://s1373.photobucket.com/user/Frednation/media/N63%20valley%20drain_zpszhwqpnk7.jpg.html?sort=3&o=0
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Tiny hole in the valley at the rear of the block, right side of photo.
http://s1373.photobucket.com/user/Frednation/media/IMGP0538_zpsbs7ounsw.jpg.html?filters%5Buser%5D=138568087&filters%5Brecent%5D=1&sort=1&o=0
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Should I ask why we have a picture of a new bare engine block
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Thanks for the picture
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It’s not a new block but one from my E70 I just went completely through because it needed rod bearings and chains with only 67K miles. I posted the photo for Matt to see the valley drain hole visible at the rear of the valley right side of said photo. If you scroll left and right arrows of that album there are many more photos of the assembly.
Please delete the link if needed.
Thanks for your ongoing help your blog is the best ever for BMW guys.
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Hey thanks for the pictures
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I just found a turbo coolant leak in my last oil change. Instantly I worried a little bit but within a quick interval of time, the mechanic resolved all the issues and made my BMW trouble free. So, I want to put my opinion that there are various leakage occur during the car usage. So, don’t be panic in such situations and take the help of a professional in order to over come from the situation. Ya, it is true that problem occurs but proper maintenance of car reduces the % of occurrence. So, it is good to take regular inspection of the car in order to avoid unwanted situation while driving on the road.
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hi is it possible to have a post on how to check if the turbo oil lines (under the turbos, deep in the engine) are leaking? i’d like to get my hand in there somehow and confirm if that’s the source of my oil leak or something else i.e. rear main seal.
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The turbo oil return line usually don’t leak because they are all steel lines,,,,check the turbos if they are leaking where the exhaust and intake part of the turbo is clamped together,,,,if that looks ok then usually the leak is under both turbos where the turbo oil line bolt into,,,,it is a metal housing that has a built in gasket which leaks oil over time,,,,and the leaks out the back of the engine by the rear main seal,,,,the only why to see this is with a bore scope ,,,,or you start removing the turbos to get a better look down there.
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Over the last couple of days I have experienced a worsening coolant leak in my BMW. Finally prior to two days I had taken my BMW to the nearest service center and after giving a thorough inspection my service ad-visor tole me that the main cause of the problem was the coolant line’s from the turbo’s were leaking and it was the cause of loosing coolant at an alternating rate. Initially I was worried a little bit but thanks to that mechanic who made me comfortable after sometime just by resolving the issue. Thus, on a overall basis I would like to say that it is just like other types of leakage in the car. So, it is better to provide regular inspection which will help us to catch up the problem and fix it at its initially stage.
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Yes regular inspections are worth it,,,,,you never know what you might find.
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Hi, when you are change the Y-Hose how do you reach the screw on the clamps directly at the engine? Have you dismounted the generator?
P.S Saw the hint with the screw + generator = sparks to late. Hope that I have nothing destroyed after this firework 😦
BR
Simom
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Lol,,,sparks will fly,,,,,disconnect the battery and remove the alternator if you can,,,,,what I use is a lone flexible drive that is 18 inches long and a 6mm socket at the end to loosen the hose clamps
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Would this coolant crossover hose be the same on the S63? I’m getting huge coolant steam coming from under the hood, right behind the Alternator area. Thanks!
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Yes it should be the same hose
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Is BMW part number 17127576363 the correct part number?
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That I don’t know,,,you would have to ask a BMW parts guy
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Actually, the E70/E71 S63 crossover 3-way is slightly different – with three quick-release caps, instead of hose clamps needed. Part number is 17127589732.
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Nice
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BMWtechnician are you working again hopefully?
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Yes I’m working,,,but the BMW industry is changing for the BMW techs,,,we got rid of 16 techs do to no work,,,,another 5 tech left because work was so slow and they are cutting are pay and took away bonus money from us,,,so all the decent techs are going to TESLA,,RIVIAN,LUCID,,,,because the pay is ok and it is hourly no more flagging hours,,,and they are giving stock options and health insurance is way cheaper for a family,,,guys are saving about $700 a month on healthcare for there family,,,so it make sense to make less hourly because they are saving on healthcare.,,,so what happen with BMW techs are not trained,,,a lot of screw up at a cheaper rate tech,,,so that why you hear about horror story’s when going to the deal for repairs,,,,sorry I had to vent about this because it is effecting my life and family’s during these tuff times,,,,,hope everything is good and safe out in the world
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Go out and start your own independent BMW shop. I’d rather support a skilled independent master tech than pay the dealership flat rate. We need more Indy shops.
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Thank-you for your GREAT service to our industry! Sorry to plug up this thread.
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