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That a lot of 325 and 330 engines burn oil is not news. But if you’re unaware, here’s a good video from E46Fanatics user 50sKid that unpacks and summarizes the issue quite nicely.
Watch it before going further, as it explains everything you need to know.
I want to make a point here to recommend 50sKid’s YouTube channel in general. I’ve watched a bunch of his videos and they’re some of the best and most informative mechanical/car DIYs I’ve ever seen. Certainly the best I’ve seen for the E46. https://www.youtube.com/channel/UCml-eeSLJZ38Q5_sUnUXrZw
If your M54 engine is losing oil, you don’t have any leaks, and your maintenance is all up to par–then this modification, commonly referred to as the “02Pilot” mod, named after the guy who created it, might be the answer to your problems. An oil catch can (OCC) is another solution that works quite nicely and follows the same principle–increased crankcase vacuum. If you want to delete the CCV entirely, the OCC is actually a better option. The 02Pilot mod is a good option, in my opinion, because it’s simple and cheap. There are no drawbacks to the 02Pilot mod that I know of, but the OCC does has a few–you have to drain it, it could freeze in the winter, etc.
Before I did this, my engine was consuming roughly 1 quart per 900 miles. After I did this, the oil light didn’t come on for 2,500 miles.
User 02Pilot, on Bimmerforums, came up with this. Here’s the original post from way back in 2012.
When I did this, it was secondary to the cleaning of the IAC and throttle body. I have not yet replaced the CCV, which I now intend to do. I wanted to test this out before I replaced the CCV, because if it didn’t work, I would have gone with the oil catch can.
READ THROUGH THIS ENTIRE DIY BEFORE YOU TOUCH ANYTHING ON YOUR CAR. THEN READ IT AGAIN. MAKE SURE YOU ARE AWARE OF THE SITUATION AND HAVE ALL NECESSARY PARTS. IF YOU ARE AT ALL UNSURE OF YOUR ABILITY TO DO THIS WORK, OR ANYTHING LIKE IT, TAKE YOUR CAR TO A MECHANIC.
I highly recommend that you clean the IAC and throttle body when you do this. The beginning procedure is exactly the same. If your throttle body and IAC haven’t been cleaned, and your upper and lower intake boots are original, I recommend you order new upper and lower intake boots, in addition to a new throttle body gasket. Because I ran out of throttle body cleaner while cleaning the throttle body, I used regular Seafoam to clean the IAC, followed by a bit of PB blaster. Throttle body cleaner is probably preferable for both the IAC and the throttle body.
Things to figure out before starting this:
– What ports are in use on your intake manifold? This will decide what parts you’ll buy.
– Are you going to clean the IAC and throttle body? It would be stupid not to. Buy throttle body cleaner and do it. Either way, you’ll need a new throttle body gasket.
– Are you going to replace the CCV system? There’s a lot more to be done in that case, so just use this as a guide for running a vacuum line to from the intake to the new CCV unit (Scroll to the very end of this post for more info about replacing the CCV)
– Does your DISA need to be repaired or does it need a new o-ring? If so, you’ll need a DISA repair kit or a new o-ring. The repair kits all seem to include a new o-ring. Go here for more info about DISA o-ring size.
– Do you have enough experience to do with sort of thing? If so, keep reading. If not, use the information included here to help you when you talk to your mechanic.
If both smaller ports are in use on the back of your intake manifold–meaning you have a car with an exhaust flap–you have to use the larger 7mm port. If you do this, you will need to either use a 7mm ID hose with a reducer, or the special Mercedes part that I used. DO NOT USE A VACUUM T on the hose going to the exhaust flap. I did that the first time and it would often take the car more than a minute for the exhaust flap to close, sometimes leaving it rattling while the car idled right after start up. If you’re cleaning the throttle body and IAC, make sure you have throttle body cleaner and a new throttle body gasket. If you’re replacing the CCV, this DIY will not have enough info for you. It’s still probably worth it for a clear explanation of what you do with the vacuum hose.
What ports are in use on the back of your intake manifold?
The vacuum ports are located here on the intake manifold:
To figure out which ports are in use, remove the cabin filter and tray, then feel behind the intake manifold to find out. The DIY link to remove the cabin filter and tray is below in step 1, and the photos you’ll need to understand what you’re feeling back there are below in step 5. Also, if you have performed the “golf tee mod” on your car–by removing the vacuum hose at the exhaust flap and plugging it with a golf tee or something similar–you can use one of the smaller ports on the intake manifold, allowing you to only use 3.5mm vacuum hose: https://forum.e46fanatics.com/showpost.php?p=17098319&postcount=16
required • Mercedes vacuum adapter
I went with this part because it perfectly angles in the direction you want the vacuum hose to go in, and it’s just cleaner overall. (Edit: An e46fanatics user mentioned this connection loosening and coming apart. I never had this problem, but can see how it wold be possible. I’d recommend a small zip-tie on the connection if you’re concerned.)
required • Throttle body gasket
(You need a new gasket when you remove the throttle body which you will be doing here. Make sure to verify fitment to your specific application before ordering.)
required • Vacuum hose
I recommend getting two meters of this so that you have a bit extra to replace other hoses while you’re in there, such as the line to the exhaust vacuum canister. This is the best vacuum hose you can buy, in my opinion. It’s covered in braided cloth, is thick, and made in Germany by CRP. Very heavy duty.
required • Vacuum connector
You want the 1/8″ connector from the linked kit. For this part, if you can get it elsewhere, you need something between 1/8″ and 3/16″, or 3mm to 3.5mm.
optional • Genuine BMW Upper intake boot
optional • Genuine BMW Lower intake boot
optional • Throttle body cleaner
optional • DISA repair kit
To keep track of oil consumption moving forward, now is also a good time to change your oil using the right stuff.
Step 1 •
It is possible to access the port on the CCV unit without removing the throttle body. As you can see in the second note below, it was mentioned to me by a few people. I checked myself yesterday, and noticed that, if you detach and move the electrical distribution box, you can access the CCV without removing the throttle body. You have to detach that box anyway, to remove the throttle body. This is probably why I thought it necessary to remove the throttle body as well. I wasn’t working in that area, so I can’t tell, exactly, if the lower intake boot needs to be removed to detach the electrical box. Either way, I still recommend that you remove and clean the throttle body and IAC. The DIY I linked to still explains all steps involved here in step 1. The hardest part is removing and then replacing that lower intake boot–the throttle body is easy. If you’re doing any of this, and as far as you know it hasn’t been done, or hasn’t been done recently, just remove and clean the throttle body and IAC.
Before you go forward and begin, you should know that reinstalling the hose clamps on the lower intake boot is, by far, the most difficult part of this. I didn’t even use the same hose clamps when I reinstalled the lower intake boot, opting to go with a keyed hose clamp. They look like this:
Removing the hose clamps on the lower intake boot is quite difficult, but putting them back is even harder. Especially if you’re installing a new boot that hasn’t conformed to the clamp. If you’re now aware of the difficulty associated with this, you can perform all of step 1, which includes the removal of the lower intake boot. Proceed at your own risk.
(Note: It might be possible to access the CCV from under the car. I cannot confirm this. It’s definitely not possible on the xi. If you’ve checked and believe you’re able to access the CCV from underneath your car, you might be able to get away with only removing the belly pans and the cabin filter/tray. More on that:
Remove the cabin filter and tray, the airbox and MAF, the upper intake boot, the DISA, the plastic panel on by the driver’s side strut tower, the lower intake boot, the IAC, and the throttle body.
(Note: Some people are reporting that they were able to access the CCV without removing the throttle body. While this might be possible–I don’t know, it was too tight when I did it–I still think you should remove and clean the throttle body while you’re in the area. It’s quite easy to remove the throttle body, but very difficult to remove the lower intake boot. It might be worth it, if you have a new lower intake boot and a clean throttle body, to access the CCV without removing them–if you’re able to:
Follow this very good DIY to perform step 1.
As you start to get the intake and DISA removed, you’ll notice the CCV here:
Keep going until you have the throttle body off.
Step 2 •
Remove the cap from this capped port on the CCV:
You should be able to pull it off with your fingers, but you can CAREFULLY use pliers if you need to. If you break the plastic nipple on the CCV, you’ll need to buy a new CCV.
Step 3 •
Take your vacuum hose, attach it temporarily to the CCV, and route it to the port on the intake manifold you intend to use so that you have enough hose without much slack, but not so that it will by pulling on either the intake manifold or the CCV connection. You want it loose, but not hanging out of place. I ran it under the throttle body. Unfortunately, the pictures of the hose routing were blurry when I uploaded them. I’ll take more pictures when I go back in to replace the CCV. The exhaust is on the other side of the engine, so you can’t do to much to mess this up. Just make sure it won’t get pinched when you reassemble, and it isn’t too long. Once you have the hose routed the way you want, knowing you have enough length, cut off the excess with sharp diagonal cutters.
Step 4 •
Pull the hose off the CCV so you have space to work and you know you’re not tugging the hose off of it, and attach the male-male connector between the hose and the Mercedes part I recommended. Your vacuum hose is now ready to be attached to the CCV and the intake manifold. (You might want to use a small drill bit-NO DRILL, USE YOUR FINGERS-to clean out any burrs or irregularities in the inside of this male-male vacuum connection.)
Step 5 •
This part is difficult/annoying because you won’t be able to see anything. Everything will be done by feel.
In this photo link–not my photo—you can clearly see the nipples on the intake manifold. #2 is the larger 7mm port, and #1 is the smaller port that might be capped and available to use:
If the smaller one is in use, you will need to go with the larger port. In this photo–this one is mine–you can see the Mercedes part (#1 in the photo) attached to the larger port. Part #2 is the male to male vacuum connector:
Remove the nipple from the port you plan to use. This might be difficult. If you can’t get it off with your fingers, use needle nose pliers to CAREFULLY pull off the vacuum cap without breaking the plastic nipple. Don’t be an idiot. Do this carefully. You don’t want to replace your intake manifold.
Step 6 •
Attach the hose to the CCV, route it the way you mocked it up in step 3, and attach the Mercedes part to the 7mm port on the intake manifold. You’ve now completed the “02Pilot mod!”
Step 7 •
Reassemble everything in the reverse of how you took it apart. Be careful not to kink or damage the new vacuum hose running from the CCV to the intake manifold.
(Please feel free to contact me regarding any errors, typos or incorrect statements in this DIY. Thanks for reading!)
Here’s a good bit of into about replacing the CCV:
Even though I don’t personally like video based DIYs, this is the single best explanation/DIY for replacing the CCV I’ve been able to find:
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