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M54 vacuum tubing ... what diameter ... what brand ... what material ... what length?

160K views 119 replies 21 participants last post by  shalang 
#1 · (Edited)
I'm tracking down a persistent lean condition and am at the point where I need to replace the set of vacuum hoses on my M54 engine ...

Q1: Does a complete vacuum hose kit exist?

I've never bought vacuum hoses before ...

Q2: Should we buy only the BMW part number or will your basic auto-parts store vacuum hose do (or should we seek a certain brand and/or material)?

For example, today, this hose literally crumbled in my hands as I inspected it for leaks:
 

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#50 ·
Thanks. I wanted to get a photo showing the SAP electric valve viewed from the firewall, but it's just too close for my phone camera to focus.
 
#51 ·
To add to the detail on how the M52 CVV supplies vacuum to the FPR:

The CVV receives vacuum from the line that bayonetts (it is not a push on & click fitting) onto the front of the CVV with a 90 degree CW twist and runs up to front of the intake manifold distribution piece. If you buy a new CVV, its vacuum port is capped and should remain that way for the M54. For my 2000 528 I pulled off that cap and attached the vacuum line that runs to a stainless steel tube that runs along the top of the fuel rail. Another vacuum hose is attached to this SS tube at the rear of the engine and runs to a hard plastic vacuum line that goes down to the FPR located just in front of the fuel filter under the car (under the driver's seat).

Hope this helps complete the detail.
 
#52 ·
The M52 CVV receives vacuum from the line that bayonetts (it is not a push on & click fitting) onto the front of the CVV with a 90 degree CW twist and runs up to front of the intake manifold distribution piece. If you buy a new CVV, its vacuum port is capped and should remain that way for the M54. For my 2000 528 I pulled off that cap and attached the vacuum line that runs to a stainless steel tube that runs along the top of the fuel rail. Another vacuum hose is attached to this SS tube at the rear of the engine and runs to a hard plastic vacuum line that goes down to the FPR located just in front of the fuel filter under the car (under the driver's seat).
So this information isn't lost, I'm going to add it to this thread:
- Sorely needed clarification on how the M54 CCV vacuum port works on the M52 CCV valve connection to the fuel pressure regulator connection (1)
 
#54 · (Edited)
Huge thanks for this thread !
It veered into an endcap discussion, but I am going to first try the 3 major vacuum hoses.

3 questions about each module:

1) CCV vacuum hose. #6 in the diagram.
Is this capped off on the M54? Do I need to buy this?
If not capped off, where does it connect to on the other side?
Is this hard to get to?
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=11_2194&hg=11&fg=15

2) Intake vacuum hoses. Any surprises here?
a) Is it hard to connect #4 behind the intake (into valve #5)
b) Does one order length cover both 4's and 7 ?
c) Also, what is the deal with #9? Do I need to buy anything here?
d) Should I replace #3 also (vacuum pipe) BlueBee was saying it was very brittle.
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=11_2203&hg=11&fg=45

3) Fuel filter/MAF vacuum hose.
Is this hard to connect? Or is everything accessible?
All I need to do i connect the F-boot to the thing near the firewall, right? (I don't need to go down to the fuel filter area, right?)
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=13_0918&hg=13&fg=10


Thanks!
 
#56 ·
Huge thanks for this thread.

1) CCV vacuum hose. #6 in the diagram. Where does it connect to on the other side? Is this hard to get to?
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=11_2194&hg=11&fg=15

2) Intake vacuum hoses. Any surprises here?
Is it hard to connect #4 behind the intake (into valve #5)
Also, what is the deal with #9 ?
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=11_2203&hg=11&fg=45

3) Fuel filter/MAF vacuum hose.
I'm aware that it connects to the MAF intake boot.
Is this hard to connect? They are pretty far from each other.

Or do they connect to a fixed pipe at each end?
Does 1) a short length go from the boot to a pipe in the engine bay,
and 2) another length connect from the fuel filter area to a pipe end down below?
(Or do you only do 1?)
http://www.realoem.com/bmw/showparts.do?model=DT63&mospid=47587&btnr=13_0918&hg=13&fg=10

Thanks!
1) there is no hose #6 on your 2001 530i CCV. Instead there is a 3.5mm vacuum cap. It is difficult to reach. You would probably have to remove the intake boots and move the electrical junction box out of the way at a minimum. Note that the electric valve is not oriented as shown in the diagram. It is in fact rotated 180 degrees so that the nipple that points up in the diagram is actually pointing down. This means that the hose from the end of the electric valve which goes to the one-way valve actually crosses the hose from the SAP valve that goes to the nipple that points down.

2) #9 is a vacuum cap. IIRC, it's 7mm. Yes it is hard to connect the vacuum tube to the electric valve, but it's possible. You just have to work blind. On my 2001 530i, there is a hard plastic pipe that the hose connects to. The pipe runs along the left side of the valve cover under the oxygen sensors wires.

3) The diagram actually shows all of the hoses from the FPR to the intake boot. The hose from the intake boot goes to a hard plastic pipe in a clip. There is a small plastic piece that adapts the plastic pipe to the correct size for the clip. Be sure not to lose that. The easiest thing to do is to follow the hose from the intake boot to the plastic pipe.

If the vacuum hoses are original, they will be well stuck to the connectors. I found the best way to remove them was to slice the hose along the nipple and then peel them off.
 
#57 ·
Thanks Steve! (And Blue)

I will just skip all end caps.
I will replace #4 and 7 on the intake with one order of hose. (11657803732) $18
I will replace the #13 MAF/F-boot hose with another order of hose. (11727545323) $5

Sounds like the right plan?
 
#58 ·
You can reach the end caps on the back of the intake manifold. I suggest you replace the large cap. Mine was cracked. The cap on the CCV can wait until you replace the CCV, which is probably sooner than you think if it is original.

You might want to buy 1/8" or 5/32" ID vacuum hose from an auto parts store as Bluebee suggests. It will much cheaper than buying #4, #7, and #13 from the dealer. 1/8" (0.125") tubing will be tight, so you may need to use a little lubricant to facilitate installation. 5/32" ((.156") may be a little loose. 3.5mm is 0.138". Your choice, but either will probably work.
 
#61 · (Edited)
realOEM says 3.3 (not 3.5)
3.3mm = .129 so I'll buy 1/8" (.125)

Tim, I sort of glossed over the caps debate.
First, I'll buy the $3 cap you noted, but are there any additional caps I should replace for a 2001 M54 530i?
(That are easy to get to....) If yes, got the part numbers/RealOEM link?

PS: Have you tried my website? www.furiousmethod.com
It's my way of thanking the BMW forum...
 
#62 ·
Thanks,
Sorry about the 3.5mm. I shouldn't type that early in the morning! I had the opportunity to have my intake manifold off this past weekend & I saw 3 caps - the 7.0mm one on the back of the intake manifold, the 3.3mm one on the back of the intake manifold & the 3.3mm one on the CVV.

By the way, for whatever reason, some of the parts don't show up on the E39 parts lists (like this cap) do show up on other M54 engined vehicles like the E83 X3 or the E46 3er.

I have tried your website. It's great!
 
#66 · (Edited)


This literally took me 2 hours to do.
This MAF/F-boot hose was TOTALLY baked on.
Petrified. I had to HACK away at it with a utility knife.
If was a very awkward position, as your hand can barely get in there.

Also, this was actually slightly dangerous, as I could have EASILY sliced my hand or fingers open.
It was EXACTLY like trying sharpen a pencil with a pocketknife. What a nightmare.

I was very tempted to just cut off the top of the plastic tube I was trying to clean off with wire cutters,
but I didn't want to pinch or crack the plastic tube I was connecting this vacuum hose onto.
At least an hour on this, and look at the sh*tty hack job I ended up with. I didn't even get all of the old hose off.
There was NO WAY the rest of the hose was coming off with that awkward angle for my hands.

This job was really idiotic to do, in hindsight.
There was nothing wrong. I sucked on the hose, and there was suction & no leak.
All my tugging and yanking trying to scrape the sh*t off risked more rupture/damage than a decade of exposure to any engine heat.
And I have NO idea where that plastic hose goes to. Somewhere down into oblivious in the engine bay.




Next, I was trying to replace the 2 intake vacuum hoses. (the two #4's)


I got the one attached to the SAP valve replaced.


But, I'm not even sure the size is correct.
RealOEM states 3.3mm = .129 so I got 1/8" (.125)
This doesn't look only .004 mm's different, however.
Unless the outside is just wider b/c of age and hardening to shape.


I was not able to find the 2nd hose.
I have no idea where this plastic tube goes....
Anyone have any clue where this red hose actually is???
That #3 appeared to wrap around the entire engine, and the disappear in the back.


I only found the plastic tubing below. Is this still #3 going all the way around back of the engine? (Not like the realOEM diagram)
This is the view from the passenger side of the engine bay


From the driver's side of the engine bay, standing above the airbox.


Where is the red hose !?!?
 
#68 ·


This literally took me 2 hours to do.
This MAF/F-boot hose was TOTALLY baked on.
Petrified. I had to HACK away at it with a utility knife.
If was a very awkward position, as your hand can barely get in there.

Also, this was actually slightly dangerous, as I could have EASILY sliced my hand or fingers open.
It was EXACTLY like trying sharpen a pencil with a pocketknife. What a nightmare.

I was very tempted to just cut off the top of the plastic tube I was trying to clean off with wire cutters,
but I didn't want to pinch or crack the plastic tube I was connecting this vacuum hose onto.
At least an hour on this, and look at the sh*tty hack job I ended up with. I didn't even get all of the old hose off.
There was NO WAY the rest of the hose was coming off with that awkward angle for my hands.

This job was really idiotic to do, in hindsight.
There was nothing wrong. I sucked on the hose, and there was suction & no leak.
All my tugging and yanking trying to scrape the sh*t off risked more rupture/damage than a decade of exposure to any engine heat.
And I have NO idea where that plastic hose goes to. Somewhere down into oblivious in the engine bay.


I found the easiest way to remove the small hose from the F connector is to slice it longitudinally, then peel it off. The other end of that small hose attaches to a hard plastic tube that goes to the fuel pressure regulator on the fuel filter. I also sliced and peeled the 1/8" hose off the plastic pipe.

Next, I was trying to replace the 2 intake vacuum hoses. (the two #4's)


I got the one attached to the SAP valve replaced.


But, I'm not even sure the size is correct.
RealOEM states 3.3mm = .129 so I got 1/8" (.125)
This doesn't look only .004 mm's different, however.
Unless the outside is just wider b/c of age and hardening to shape.


I was not able to find the 2nd hose.
I have no idea where this plastic tube goes....
Anyone have any clue where this red hose actually is???
That #3 appeared to wrap around the entire engine, and the disappear in the back.


I only found the plastic tubing below. Is this still #3 going all the way around back of the engine? (Not like the realOEM diagram)
This is the view from the passenger side of the engine bay


From the driver's side of the engine bay, standing above the airbox.


Where is the red hose !?!?
That hose from the SAP valve connects to the plastic pipe that runs under the oxygen sensor wires along the right side of the valve cover. On my car, that plastic pipe runs toward the back of the engine where it bends toward the left side of the engine. It is visible in your last photo as it passes through a bracket. There is another vacuum hose that attaches this pipe to the SAP electric valve which is on the back of the intake manifold. This pipe and this hose are the "red hose".

There is one more vacuum hose that connects the electric valve to a nipple on the back of the intake manifold. The valve and the hoses that attach it to the pipe and manifold nipple are almost impossible to see.
 
#67 ·
You can find 3.3mm hose at some online stores,I just ordered a meter of it,Im going to change my vacuum hoses when they arrive.Im waiting on parts( maf,cvv and hoses, ofh gasket,tb gasket,icv grommet,oil filler cap gasket,lower intake boot and disa gasket. I tackling the cvv and ofh gasket,taking care of any vacuum leaks in those areas. Then Ill go to the other side of the engine and take on the VCG and Vanos seals. I saw you on here a while back and hope everything is moving along with your repairs and maintenance. This is a Great site to learn from. Got great deal on a oe maf.
 
#71 ·
You might be able to remove the plastic pipe that goes to the FPR from the bracket and see if there is enough slack to snip off the end istead of trying to remove the old hose.

In my previous post, I forgot about the one-way valve #6. There is a short piece of hose that goes from the one-way valve and another that connects the one-way valve to the manifold nipple.

The right and left designations area standard. It's as viewed from the drivers seat.

Yes, on my car, #3 goes around the back on the valve cover through that bracket. #4 is probably 6" long.

You'll need to remove the covers and the left cabin air filter assembly to get access to the electric valve #5. You'll have to work blind or find some way to fix a mirror so you can see what you're doing.

Remove the pipe from the bracket and feel for the hose #4. Then feel where it connects to the electric valve. Note that the electric valve is mounted upside down from the orientation in the diagram. So hose #4 connects to the electric valve #5 from below the valve and hose #7 connects to the electric valve nipple that is pointed to the right side of the car. These two hoses actually cross. Then hose #7 connects to the one-way valve #6. The other hose labeled #7 goes from the one-way valve to the nipple on the intake manifold.

While you're at it replace the 7mm vacuum cap #9. It's most likely split and is not expensive.

Yes a non-pro can replace these hoses. I did.
 
#75 · (Edited)
You might be able to remove the plastic pipe that goes to the FPR from the bracket and see if there is enough slack to snip off the end istead of trying to remove the old hose.

In my previous post, I forgot about the one-way valve #6. There is a short piece of hose that goes from the one-way valve and another that connects the one-way valve to the manifold nipple.

The right and left designations area standard. It's as viewed from the drivers seat.

Yes, on my car, #3 goes around the back on the valve cover through that bracket. #4 is probably 6" long.

You'll need to remove the covers and the left cabin air filter assembly to get access to the electric valve #5. You'll have to work blind or find some way to fix a mirror so you can see what you're doing.

Remove the pipe from the bracket and feel for the hose #4. Then feel where it connects to the electric valve. Note that the electric valve is mounted upside down from the orientation in the diagram. So hose #4 connects to the electric valve #5 from below the valve and hose #7 connects to the electric valve nipple that is pointed to the right side of the car. These two hoses actually cross. Then hose #7 connects to the one-way valve #6. The other hose labeled #7 goes from the one-way valve to the nipple on the intake manifold.

While you're at it replace the 7mm vacuum cap #9. It's most likely split and is not expensive.

Yes a non-pro can replace these hoses. I did.
Steve, I really must thank you for taking the time to elaborate.

To recap, I will follow plastic tube #3 to the end (past the bracket behind the motor) and feel where it connects to a rubber vacuum hose. I will then follow that hose down past the electric valve #5, where it connects underneath. I will then see if I can replace this hose #4 blindly.

Next, now that I can feel the electric valve #5, I will find the other hose #7 that connects to it sideways (facing towards the inside of the engine bay....towards right/passenger side..)
I will follow that 2nd hose #7 to the 1-way valve it connects to #6. If I feel confident I will try to replace this one also, blind.

Lastly, now that I have my hand on the 1-way valve, I will try to feel the other #7 hose that comes out of the other side, and goes into the intake. Do you have a photo of where this nipple on the intake manifold is? (I'm not entirely sure I even know what the intake manifold even is)

If these hoses are even 1% petrified, there is no chance in hell this will work. I spend an hour trying to scrap a plastic tube clean, while staring at it and the top of the engine way, and FAILED !! 0% chance in am slicing a tube with a utility knife, BLIND. I wonder if all this is stupid to replace. The 2 other vacuum hoses I spent 2 hours replacing today did NOT need to be replaced. This is 11 years and 120k miles in. "If it ain't broke..." I have a teapot sound but so far, it has not been the 2 intake boots I replaced or the 2 vacuum lines I've already replaced. I guess a smoke test should have been the first step, but I had no idea it would be this much work to replace.
 
#72 ·
I replaced both the hoses from the f-connector on the air tube this weekend. They fell apart when I was removing the air box. Luckily I had some leftover silicone hose of a varying sizes from when I did vac hoses on my Miata.
 
#77 · (Edited)
This is a very nice write-up. It answered questions for me. I'm not sure of one thing.

History:
My mechanic replaced all vacuum hoses and blocked off the Cabin air temp sensor because it was a massive vacuum leak. I think either there was an "air restrictor" in the line near where the hose connected to the intake manifold or he put the hoses in the incorrect position, if that matters.

First Picture:
I don't know what angle this was taken from but it looks like the hose to the one way valve is where my hose to the cabin temp sensor is and, in my case, the 3.5 that is blocked off goes to my one way valve.

Second Picture:
This looks like what I can feel for the one way valve connection and capped off 7mm, but my cabin temp vacuum hose connects below the two about halfway between. In this pic I see what looks like a wire (more so than a hose) connecting straight up to where that would be but it's not visible because of the larger wires in front of it.

Third Picture:
The back of my intake manifold. The hose without writing on it goes in through the firewall. You can see the one way valve on the other hose.

Forth Picture:
My cabin air temperature sensor. I think maybe Canada used a slightly different system as most references to the temp sensor seem to place it in the center console. There's just no way should the cabin hose be able to run wide open as the sensor is 100% passive by design.

So, Does it matter where the hoses connect to the intake manifold? If so, what's correct?
Did he chuck something out that restricts the air flow?

Thanks -Bob
 

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#78 ·
Bob.

Those first two photos are mine. As you can see, there is no vacuum hose attached to the second nipple on the intake manifold. I agree that the cabin air temperature sensor you have must be specific to your Canadian model.

I am not certain, but I think that both of those vacuum ports have a direct pathway to intake vacuum pressure. I think they are equivalent.

I measured the vacuum at the 7.5mm nipple as over 20" Hg at idle on my car. That is a pretty strong vacuum, and it would seem that there might be considerable flow through that hose if it is not restricted.

That said, I have no idea how the cabin temperature sensor works on your car. I would be surprised if there is no one-way valve on that line. Otherwise there would be a direct passage from the intake manifold to the cabin. Of course, that one-way valve might be integral to you cabin temperature sensor.
 
#79 ·
Thanks Steve. I can see now that those two are actually the same. The angle hides the 3rd connection from view. My hoses are reversed, but from what you say it makes no difference.
I did find a forum on another site from 2008. It went something like this:

........

Member "B": Your restrictor is probably missing

Member "A": Do you have the part number?

Member "A": Never mind, I found it.

I managed to contact "Member "A" and he had sold the car and doesn't remember a thing. (So close...)

Member "B" is no longer a member.

I take this as a strong indication a part was discarded in error (not his only error, BTW).

I hope someone on "Bimmerfest" has a parts manual that shows this part and it's location. I cannot find it in any on-line manual.

Thanks again! -Bob
 
#80 ·
Bob,

I assume you have the HVAC system with dials, not the automatic system. If so, that system is called the IHKR. That might help search for the part.

BTW, what problem are you having?

Steve
 
#81 · (Edited)
JimLev thought IHRA, I have no idea how I'd know. Yes, dials.

I know the sensor is used to maintain a constant cabin temp and I understand why a small air flow would help. I would like to have it working as it did before the mechanic did whatever he did. I also now get SAP codes p0491 and p0492. I get the codes everytime with the hose connected to the sensor and once in a while when It's capped off.

I hope tomowwow is as nice as the forecast promises (it's hailing at the moment) so I can take a look in the driveway. I hope to find a tee junction in the SAP line with a restrictor hanging cause that would mean that 3rd hose should have been there and the connection on the manifold should have been capped. This would explain the occasional SAP code with the sensor capped.
 
#82 ·
JimLev is usually right, so go with the information he provided.

You should check the vacuum hose that runs to the SAP valve. Other than that, the problem could be the electric valve, SAP valve or the air pump. My bet is that there is something wrong with the hose since your mechanic worked with that.

I don't understand why the mechanic would remove that hose rather than replacing it. It's not like you don't need the interior air temperature sensor.
 
#83 · (Edited)
Easier to cap it off and call it bad, I guess. He did manage to charge me for a dash removal before he "solved" the issue by capping the hose. He didn't remove the hose. He capped it at the sensor. I have a feeling he may have removed all hoses and then reattached them from memory. The hose to the SAP valve was replaced. but I plan to check it all. Thank's to this site, I know what to look for everywhere except for this climate hose and I have my suspicions here. Once I look it over if I don't see the obvious I think a visit to the dealer's parts department in Moncton might reveal a missing part.

This, if his fault, will be the third "coincidence".

One and a half months to replace vacuum lines, valve cover gasket, and a CCV job. No dealer in my city. Scared to take it back to him.
 
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