DIY - Intake Plenum Removal

[JCtx]

I initially asked for a DIY, but ended up doing it myself . It starts on post #3. Hope this helps.

[mikewads]

I would also like to know how to remove the intake cover thats hiding the 8 throttle bodies. I removed the (2) chrome nuts also, but the cover would not budge.

[JCtx]

I wanted to remove the plenum to check the idle control valve's hose, which supposedly disintegrates at some point and the debris causes the valve to fail, but I didn't find that to be true: other than a 1" manual clamp to connect to the plenum, it's a regular rubber hose attached at both ends with those pesky BMW clamps, so couldn't check anything. Plus there's still a lot of crap to remove to get to the valve and strips anyway, so my job ended there, other than cleaning everything and checking bolts (the ones securing both PCV valves were pretty loose in my car, so give them a nudge). I'd NOT accept a hose replacement as fix; insist on a new idle valve.

Here's the procedure to remove the plenum (installation is in reverse order):

1. Remove air filter cover (8 T25 screws that don't come off the lid -nice). Wiggle the sucker out. There're DIY for air filter replacements if you can't do it, but I wouldn't continue if you have difficulty removing that cover .
2. Remove the 2 10mm bolts that secure the bottom of the air filter housing and just pull sucker out.
3. Dislodge passenger's side sparkplug cover by pushing out from the bottom at both ends. Once loose, you'll have to remove the 2 10mm bolts holding the coolant reservoir in place, push it to the front to dislodge it from the green grommet on the wheel well, and wiggle both (one with each hand) until you can remove the cover.
4. Remove driver's side sparkplug cover. It dislodges in the same manner as passenger side, but comes out much easier. Just dislodge fuel hose from the top, and wiggle it under the hose.
5. Remove a plastic hose connected to the small piece between plenum and air filter housing; it has a manual clamp so piece of cake.
6. Remove plenum connector by the oil cap.
7. Loosen up all 8 TB (throttle body) clamps with either a long screwdriver or a 6mm socket with extensions.
8. Push the plenum up to break it loose from the TBs.
9. Once loose (it's easier), you need to disconnect another TWO hoses UNDER the plenum, both with manual clamps as well: a small one is in the front, below the 'snake' going to the air filter, and the big one at the rear, on the driver's side, where the brake booster should be. And finally, you need to remove the driver's side PCV valve from the valve cover. It has 4 T30 screws. You need to wiggle it as you push out, since there're an O-ring on the cavity forward of the engine that will make it a little hard.
10. Now the plenum will come out.

[JCtx]

Here's a picture of the naked beast (now squeaky clean), in case the gang needs proof :



I decided to remove the front engine hanger for less clutter (see pic above), both sparkplug covers, and all 4 grommet studs (replaced them with 10mm bolts for a factory look). Engine looks gorgeous now, plus that area will run cooler now, water doesn't get there, and no more hassle to remove them. After removing the blue paint from the torx bolts (had to sand them down; don't know what the heck that was), here's my new engine look:

[mikewads]

Good info and thanks for the pictures elp_jc!

So... the top of the plenum does not come off right? The only way to see underneath is to remove the entire plenum assembly?

[JCtx]

Originally Posted by mikewads

So... the top of the plenum does not come off right? The only way to see underneath is to remove the entire plenum assembly?

Correct, so don't even bother removing the top chromed nuts. Seems like the top cover is glued/epoxied to the bottom, and the 2 chromed nuts keep both halves tight while curing. Glad I could help . Take care.

[SouthShoreM3]

Originally Posted by elp_jc

I wanted to remove the plenum to check the idle control valve's hose, which supposedly disintegrates at some point and the debris causes the valve to fail, but I didn't find that to be true: other than a 1" manual clamp to connect to the plenum, it's a regular rubber hose attached at both ends with those pesky BMW clamps, so couldn't check anything. Plus there's still a lot of crap to remove to get to the valve and strips anyway, so my job ended there, other than cleaning everything and checking bolts (the ones securing both PCV valves were pretty loose in my car, so give them a nudge). I'd NOT accept a hose replacement as fix; insist on a new idle valve.

Here's the procedure to remove the plenum (installation is in reverse order):

1. Remove air filter cover (8 T25 screws that don't come off the lid -nice). Wiggle the sucker out. There're DIY for air filter replacements if you can't do it, but I wouldn't continue if you have difficulty removing that cover .
2. Remove the 2 10mm bolts that secure the bottom of the air filter housing and just pull sucker out.
3. Dislodge passenger's side sparkplug cover by pushing out from the bottom at both ends. Once loose, you'll have to remove the 2 10mm bolts holding the coolant reservoir in place, push it to the front to dislodge it from the green grommet on the wheel well, and wiggle both (one with each hand) until you can remove the cover.
4. Remove driver's side sparkplug cover. It dislodges in the same manner as passenger side, but comes out much easier. Just dislodge fuel hose from the top, and wiggle it under the hose.
5. Remove a plastic hose connected to the small piece between plenum and air filter housing; it has a manual clamp so piece of cake.
6. Remove plenum connector by the oil cap.
7. Loosen up all 8 TB (throttle body) clamps with either a long screwdriver or a 6mm socket with extensions.
8. Push the plenum up to break it loose from the TBs.
9. Once loose (it's easier), you need to disconnect another TWO hoses UNDER the plenum, both with manual clamps as well: a small one is in the front, below the 'snake' going to the air filter, and the big one at the rear, on the driver's side, where the brake booster should be. And finally, you need to remove the driver's side PCV valve from the valve cover. It has 4 T30 screws. You need to wiggle it as you push out, since there're an O-ring on the cavity forward of the engine that will make it a little hard.
10. Now the plenum will come out.

Hey hows it goin! I was doing some research as to how to remove the plenum and i appreciate you taking the time to write this up, but i have a few questions if you dont mind helping me with.

!) i removed pretty much in the engine bay that you recommended and was looking at the TBs and i can do the first 2 rows of TBs, but how do you get to the last two rows as i cant even see the final 2 TBs.
2) If you remove the first 2 TBs will it become easier to get to the other 2 rows?
on the Plenum there are those two black connectors on each side where the blue TORX bolts are....do you remove those pieces? Also how do you get the bolts on the passenger side if you do reomve this or will the Plenum just pull out of those black connectors when removing TBs
3) Why do you remove the Spark plug covers? just for easier acces?
4) What is this step??? And finally, you need to remove the driver's side PCV valve from the valve cover. It has 4 T30 screws. You need to wiggle it as you push out, since there're an O-ring on the cavity forward of the engine that will make it a little hard.

Any advice to get to the final two rows of TBs would be greatly appreciated....I am completely lost and dont want to pay $$$$ to bring it to the dealership

[JCtx]

Originally Posted by SouthShoreM3

have a few questions if you dont mind helping me with.

Not at all, but remember I did this over 2 years ago . All I can tell you is the TB bolts are at the same exact location, so you know pretty much where they are. Forget about using a screwdriver; you need a socket, and 2 long and 1 short 1/4" ratched extensions. Most kits come with 1 and 1, and I had another long one from a smaller tool kit. But even when all 8 TBs are loosened up, you'll have to push it up little by little until it finally pops, so forget about pushing the plenum up until ALL OF THEM are loose (or you could tear the boots). You can wait until plenum pops to remove the driver's side PCV. But don't expect it to be easy to remove with the engine braces in place. It was too much trouble to remove the braces IMO, so I decided to fight them for 5 minutes until I figured out how move the plenum around to clear the bars. It WILL clear, but you'll have to figure out how.

As far as the spark plug covers, they might not need to be removed; I don't know. But I wanted them gone anyway, hence that step. I also removed the front engine hanger (engine cannot be lifted with plenum in place). My OCD side wanted a clean looking engine . Good luck man. And may I ask what are you doing in there? Please let us know. Take care.
Good luck.

[SouthShoreM3]

Thank you I actually just loosened the tbs and now that manual valve on the drivers side is a you know what! I can't get it off. I am getting in here to clean it and out on a new intake plenum.

At this point if I can't remove that valve I'm putting it back together and watching football.

Again words of wisdom appreciated since I don't have small hands to release that valve

[JCtx]

Originally Posted by SouthShoreM3

Again words of wisdom appreciated since I don't have small hands to release that valve

Is the plenum off the TBs now? Remember you need to pop the plenum up before being able to remove that valve. You might be missing a bolt on the back as well; use a swiveling mirror, since I think there're at least 3. And it has an O-ring on the head side, so it'll need some motivation to pop out as well. Good luck. You're almost there man; patience .

[SouthShoreM3]

so i got the plenum off and it poped right off....two problems occured that is going to result in me either going to the dealership and paying for 4 hours of labor or just sell the new intake plenum....

1) i have DINAN CARBON FIBER Strut Braces and as a result i cannot move the plenum up, down, left right because they are so thick. the stock struts are flat and that allows movement

2) because of this strut situation i was not able to get the valve that is close to the drivers side on the plenum cause there is just no room for my hands to pull, squeeze, and detach this annoying valve

as a result of my findings....it looks like i am going to have to take off the entire front plastic piece near the windshield, remove the strut braces, and then hope that i can get the plenum off and get to that valve by the crivers side.

So do i spend another night trying to do this and then put it all back together, or do i completely waste money and have the dealership do it....I would just hate to have to take all that apart and come to find out i still cant get it off!

4 hours of labor and have my tech at the dealership do it and know its done the right way sounds good to me....expcet its 600 dollars in labor for really a cosmetic part...but i really do want to clean everything out under there..

Lets hear it what do you think is the wise road to take? Or how to bypass taking all that stuff off =?