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DIY: Intake boot replacement. No more whistle while accelerating

199K views 129 replies 85 participants last post by  Tate325xi 
#1 ·
After seeing all of these threads on people asking why their cars are making a whistling sound at high rpm or while driving, it got me wondering what has caused this and I did some research and found that it was the lower intake boot that gets old and starts to crack, letting in unfiltered air under hard or moderate acceleration, which in turn leads to that loud whistle you may be experiencing. My car does this too so therefore I decided to fix the problem. I have made a DIY on how to do this to help fellow e46Fanatics who are experiencing this problem to fix it. Here is my DIY. Enjoy.



Difficulty: It is simple if you know your way around the engine and if you have disassembled the intake of your car before, I'd say this repair will take the average person anywhere from 45 minutes to 1 hour 30 minutes.


Parts Needed:

Tube Elbow (BMW P# 13-54-1-438-759) $12-18


Tools:

6mm, 10mm Sockets with extensions
T30 TORX Socket
6mm Wrench
3/8" Ratchet (1/4" Ratchet will help make things easier)
Needle Nose Pliers
Flat-Head Screwdriver

Instructions:

Step 1: Remove the little clamps holding together the front part of your intake. Use the needle nosed pliers to help get the clamps out.



Step 2: Remove the first part of your intake. It should look something like this when you are done.



Step 3: Remove the two bolts holding your air box in by using the 10mm socket and wrench with an extension to make it easier.



Step 4: Loosen the metal band that is around the upper intake hose with the flathead screwdriver.



Step 5: Disconnect the MAF (mass airflow sensor) by pressing down on the small metal bar on top of the connector and pulling the connector away.



Step 6: Pull apart the uppper intake hose from the back of the MAF and once disconnected remove your entire airbox.



Your engine should look like this by now.



step 7: Now its time to remove the cabin filter, you need to loosen these three clamps by pushing down and turning counter-clockwise.



The clamps should pop up if you loosened them the right way.



Step 8: Remove the lid of the cabin filter by lifting up and pulling it out.



remove the filter also.



Step 9: Now you will see 4 TORX bolts.



Remove them with a T30 TORX bit.



before removing the cabin filter, remove a black clip that is on the bottom of it holding some wires, just unclip it and pull the wires out.



Step 10: After removing all 4 TORX bolts, remove the entire cabin filter assembly by lifting up and pulling it out.



By now your engine bay should be looking something like this.



Step 11: Loosen the metal bands around the bottom and top of the upper intake hose and the intake boot, also pull out the hose leading into the upper intake hose.



Step 12: Remove the upper intake hose by pulling it off, you might need to pull hard to get it off, but once its off you will see the intake boot that you will be replacing. I circled one of the metal bands on the back of the small hose on the intake boot, try and loosen this the best you can and pull that hose off.



You may want to remove this black wall that is near the brake booster, it gets in the way and when removed will allow you better access to the screws to loosen the metal bands around the back of the intake boot. Just remove this piece by turning both screws that I've circled and pull them out, then just lift this piece out of the way.



Step 13: Feel around the back of the intake boot for the bolt on the metal band and try and see if you can see it, then loosen that and pull the intake boot off as hard as you can, its not easy to get off but eventually it will come off.

Finally got the SOB off. :censor:



This is what it will look like with the intake boot removed. To install the new one just put the metal bands from the old one on the new one and push the new one on over the big hole first then push the small tube on next, make sure you put it on really secure as you don't want any air leaks which would defeat the purpose of this repair.




New intake boot on! :D




Now to put everything back together, just follow the steps backwards and if you did it right it should be looking like this.




Finally, check over everything and make sure nothing is loose and then close your hood and start the car, let it warm up, the idle should be a lot smoother now, go for a drive and enjoy the quiet sound of your engine minus the annoying whistle.

I hope this DIY has helped you a lot. If you have any questions feel free to PM me and ill be glad to answer them for you. :craig:
 
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#66 ·
Well i was getting codes bank 1 and 2 to lean. replaced the air flow sensor and reset the light. code came back a week later. i did a smoke test and found all the vents pipes under the intake leaking. followed this DIY yesterday and what a PITA!!! did replace all the pipes and the oil separator. replaced the intake manifold gaskets, cleaned the injectors. turn the car back on and it idles very rough. haven't driven the car yet but going to work today so lets see. the light is still on but i will reset it today and see what happens. hope this was the problem.

JC86 the little tabs you are looking for are cheap from BMW. you can get it from them dirt cheap.
 
#68 ·
I just did this today and it wasn't nearly as difficult as I thought it would be. Although I had a hole in the smaller tube, I didn't have a noticeable whistle, but I did have the SES light that would not go away.

I didn't remove the cabin filter stuff or the small kick panel thing as it was only a little obstructive. Also, since the smaller tube was already split, I cut it through so I could pull the lower boot off first, then I could work on the smaller piece. It was a gamble to cut it because I had to have the car back together by a certain time for my wife to go out of town. Luckily, I was able to get to it and remove it easily.

I also cleaned the throttle body and the IAC module while I was in there. I cleared the SES light and took it for a drive.

Thanks for the write up!
 
#75 · (Edited)
Completed lower and upper boot plus DISA Gasket yesterday. I made it about about a four hour job. I was in no hurry. I did take the airbox out and went the DISA route. Left MAF in since I cleaned it several months ago. I have 59,000 miles on our 330CIC and I wanted to check Coolent & power steering tanks, hoses and belts and anything else I see. I took DISA out for several reasons. One to check gasket and it was shot. (lower than the ridge of the DISA grove...doing absolutely nothing, except leaking) The other to check for rattle and perform vacuum test and pin status. Replaced gasket with Ebay's best ($12.95) no gas or vehicle wear looking for a gasket.

I knew a had a rip in ICV hose on lower boot as I had sealed it months aqo with weather seal to get all the parts I needed to repair lower boot. My upper boot looked new so I didn't order that when I ordered lower boot. (Mistake) When I removed upper with a tug tug type pull and looked at the bottom it too looked good but when I spread out flex part, it was ripped in four places. Trip to BMW $47.10 later I was set. $29.95 German auto parts + shipping but I couldn't wait

As for the lower boot removal, I didn't mess around. Sock into trottle body I cut the boot off right at the trottle body. All of the problem clamps now fully exposed. I did use the suggestion/hint of a make shift tool in this tread to help you, was the allen wrench and 6 mm. Used this and few other tools. Once boot was out took pictures all over for the record and to see how things looked. On the lower boot I think it is better to hook up larger hole to get flange to match then the small hose . small hose clamp screw straight up so you can tighted from above Big clamp I went toward Disa hole, again for screwdriver. Putting in boot coupler and first band screw pointed toward fender. Used stubby screwdriver. Reinstalled DISA taped screws with 30 mm torx taped to my socket with masking tape. Boot covered with sock. I have a suspension support bar but that didn't get in my way. Almost There. Sock out. Installed upper boot. Don't fully tighten bracket. You need to leave loose so when you put airbox back in you can move to match the airbox. Plug back in Disa wiring ( disconnect is on engine side of plug) and MAF after installing airbox. go back tighten rear upper boot clamp. Install front air intake with three pins. Go treat your sore back and watch TV. Thanks to all for DIY to give me the nerve to do this. Went smooth.
 
#79 ·
Seek and you will Find.



UpDate: A lot of post just drop off and you never really know what fixed their problem. All of the parts above, I stated were bad. Boots & Disa Gasket. I still had that nasty smell occassionally. It turned out to be the leaky windshield washer pump's little hole at base causing water to splash on fender and to exhaust manifold and I think also maybe getting into Oxygen sensor. Read that on another post to check. My Vacuum leak was a part little mentioned but was a culprit for me. The Oil filler intake neck cap gasket on top of the engine was smashed so thin it really didn't function. Siliconed/new gasket Smell #2 and vacuum leak found. Codes PO 171 PO 174 self cleared and I immediately knew I was on to something as idle picked up 100 RPM's and the Bimmer feels great.
 
#76 · (Edited)


Anybody have any idea what the PN is, or what system its attached to? I may need to replace the little plastic piece that both hoses plug into. It's extremely brittle and i don't want it sucking something into another part of the car.

EDIT: found it for anybody that is looking: 13327503677

Such a pain in the ass. FYI, the part numbers for 325i and 330i are different. the one for mine is 13541435627
I put the one listed by the OP into the car and came up short for fitting it onto the intake box. I got it on there, but as long as there aren't any leaks, and i'm able to fit it on the MAF, should i have any problems? I do NOT want to get in there again haha
 
#77 ·
That broken small hose leads to the fuel filter under the driver side of the car. Had the exact same problem. Was getting the P0102 code. So far changed the MAF, intake boots, F connector and the two hoses and checked the connectors for any crimps. Still throwing the same P0102 code. Anyone figure this out?
 
#78 ·
I just finished this and it took me about an hour and a half. Was kind of easy once I figured out angles for getting at those hose clamps. Unfortunately, the boot I replaced did not have a hole in it, but the one between it and the air box does. Hooray. When I got to the lower intake boot, I ended up removing that wall thing, and on installing the upper boot, I ended up removing the air box. Work smarter, not harder (as my former boss at wal-mart used to say constantly).
 
#82 ·
Silicon



If you have correct boots & With DISA out.. Prepare lower boot by Siliconing boot and throttle body so it will slip on. I used pool silicon I have for "O" rings.

Before starting Install/wiggle the spacer that connects the two intake boots together on lower boot. Sorta snaps in. Easy with silicon and not connected.

With the O ring clamp screw facing straight up, make sure "lower Boot lip tag" is between and on top of grooves (they stick up) that are on top of the throttle body, push/wiggle in, Check with mirror or with fingers that the large boot is correct. Find lip grooves before installing around one O'clock on top of throttle body about two inches apart.

Slip small boot hose on with clamp.. Tighten large boot screw with long flat blade screwdriver with handle coming down from cabin filter area. Again with fingers & inspection mirror check fitting. Tighten clamp on small tubing hose I had clamp screw facing toward DISA hole. Check again clamps and tighten again.

Hope you have checked, DISA gasket, pin, vanes and did DISA vacuum check by placing finger on hole. See DIY. Take your time with "Boots out". Feel/check the hose that comes from CVV to bottom of dip stick for breaks or plugged up. Squeeze lightly. Check bottom of Coolant & power steering resorvoir for leaks. Be carefull of "F" splitter on first intake now is the time to follow/inspect vacuum lines to ICV from "F" spliter.

When installing Airbox boot end, do not tighten clamp to lower boot spacer until you have manuevered boot around so it fits MAF correctly, and fully open. Clean you MAF....Not a bad idea either.. Worked for me CRC Mass Air Flow sensor cleaner..
 
#84 ·
DISA Check pretty simple

If you are just getting car going again you can do DISA and MAF when you have time but if DISA is out give it a good inspection.. Use light oil instead of silicon to put back in. Put sock in lower boot. This is a mechanical check only. If still in: Disconnect electrical wire to DISA. A Clip on plug to push in is on the rear of plug toward engine. Lift up. Careful not to drop bolts. Towel good idea under work area. Remove DISA with Torx 30 wrench. You will hear a little click as you break seat of the bolts. Remember pressure when you reinstall. Pull straight out and then tilt DISA toward firewall to fully remove. Ask yourself, did DISA come straight out easily or with a pull. Easy means "O" ring gasket needs replacing. My "O" ring was below groove. Get one on EBAY.
Inspect DISA valve vanes/flap for signs of wiggling/flapping. Should be firm. Check large pin at end that it is fully seated and does not stick outward or have any signs of cracks. I was reluctant to pull pin just looked. Any problem here, it is junk. Pin can be sucked into intake can destroy engine. I have read where you can pull pin out and flap for emergency use of your car awaiting new DISA. Now close Flap and release, does it feel smooth and fully open when released? A very slight bump may be felt when closing when first moved. Close Flap fully and look for a small hole by the diapham. With vane fully closed put finger on hole. Release flap. Flap should open slightly 1/2 " and hold, staying closed. Release finger over hole and Vane should snap fully open. Reinstall with new gasket allowing Torx screws to pull DISA in slowly. I used masking tape on bottom DISA screws to hold to TorX socket. Pull out sock install first boot. :) If DISA goes in with no pressure order a gasket.
 
#88 ·
MPG Affected?

Thank you for this DIY. This Helped fix my idle and got rid of the "turbo whistle..." I have a 99 E46 328i. My intake boot was very badly cracked, i'm surprised something worse didn't happen. I mean you can see through the hole.

This has been a probably for me for the past 40k miles, I've just overlooked it many times. Now that it's fixed, it seems as though my throttle response has increased. But on the other hand, my MPG dropped from 26 to 24. I have only driven close to 20 miles since the replacement.

I was thinking, this may be the MAF adjusting to the change? Does this sound remotely correct?
 
#89 · (Edited)
Thanks for the writeup! I definitely had to remove the cabin filter and the heat shield next to the brake booster. Also had to unclip the booster vacuum hose and fuel vapor return line from the manifold. The clamp holding the lower tube to the throttle body was easy to get with a 2' screwdriver from under the car. At least, it's easy if you _have_ a 2' screwdriver. :thumbup: The clamp holding the smaller branch of the lower tube was a mother to get at, ultimately requiring a 1/4" ratchet and a 2" extension and extensive contortions.

I was concerned that after all this work I'd still have my whistle, because unlike most of you, I did not have a SES light or any rough running. My whistle occurred at random times, throttle openings and RPMs. Happily, I found cracks thru each accordion fold of the small tube!! It just started pouring rain, so I'll get back out and finish up when the waether improves...
 
#90 ·
Taking a break. This has to be the hugest pain in the neck job I have ever encountered. The screws for the lower boot clamps were in absolutely the worst position possible. Also three of my fingers are taped together because of a tendon injury, so maybe I shouldn't have attempted this. Oh well, it's done, now I just have to put it back together.

Also, the vacuum hose on the f connector for the fuel filter was so brittle it just fell apart, so now ill have to fix that...
 
#92 ·
Just finished! 6hrs. What a complete pain!!!!!!!

I did the temporary patch on all the cracks with super glue, then heard the crunching of the super glue as I try to reinstall the the bellows, so I took some silicone and smeared it in the ribs at the bends and around other areas. Not the cleanest looking but difinately airtight now!
 
#93 ·
those with SES light and whistle...

What codes are you showing?

I'm getting po491/492...

Took it to my indy he says needs new air pump/vac lines... going to drop it off on friday to have him do a smoke test?

I am dealing with RPM fluctuations at idle on my 325i 5MT 2001. I also have the whistle...

Looking for guidance... thank you!
 
#94 ·
Just did this today

My car has 168,000 miles and is a 2001 E46 ZHP 330i.
I have had a crazy whistle from my engine ever since I took it to the auto mechanic for an air leak I gave up on. My engine runs great. But gas mileage is very poor and I get a LOUD whistle until the engine is completely warm. It whistles at idle, when accelerating and maintaining speed. I just did this "Intake Boot" write-up DIY today. Used a factory boot. All went very smooth as I read this FANTASTIC write-up before proceeding. The whistle is still there. I see many references to possible pulley/tensioner being the source of the whistle. Are these parts expensive? I consider myself really good at DIY, but no master as I need to do research before I take on any task beyond brakes & oil. Would it make sense to just replace these parts, anyways? I plan to keep my car as long as possible... My goal is 1,000,000 miles. Any feedback is appreciated.
 
#96 ·
Sponsor sites on here. Take a look at the top of the page. I needed 13 parts total just for this diy and a couple other random things. Some sponsors didn't have the parts I needed and ordering from different websites pretty much came to the same amount I paid to get it the next day from my dealership.



Thanks for the write-up ///M=Power. :thumbsup:

I finished this yesterday. The lower intake boot's clamps were pointing towards the back of the car, at an aggravating angle. :censor: I don't have a flexible socket extension (like these: http://www.ebay.com/itm/350679813836 - which would have helped out a lot!), so I removed a bracket that was holding 2 lines, which is located to the right of the lower intake boot. Doing that made the job easier.

I also removed the throttle body and cleaned it. Mine looked pristine on the outside, but the inner part was dirty as hell. I'm not sure how just spraying tb cleaner from the outside (even with the flap open) like I've seen people do in most dyi videos would get it as clean as removing it. You'll also need to replace its gasket if you do.

My icv gasket was black as night on the inside, but was still rubbery, no cracks, not hard so I just cleaned it thoroughly. The icv slid back on easy afterwards. So, just clean it out unless you want to blow $20 on a small rubber piece.

And don't be an idiot like me and forget you have the black plastic firewall piece on a table behind you after you've put everything back. You'll never get it after you put your boots on.....believe me I tried :D swearing up a storm before giving up and taking the new boots completely off just to slide that piece back in.
 
#97 ·
Thanks for the DIY, helped me out today while I was replacing the lower boot, cracked with 136k km's on it. The screws on the lower end of the intake were turned upside down, which made it such a PITA to get at. When I installed the new ones, I made sure to keep the clamp screw on the top of the tube.
 
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