Intake valve cleaning thread
So we start off with a 335i that has 20,000 miles since its last intake cleaning. This car came in with the engine cover off, recirc by-pass valves open to atmosphere, and misc. engine cover pieces uninstalled, all of which I reinstalled. I tried to place the pictures in the correct order, but if you look closely, you will see some subtle inconsistencies between some of the photos because of this.
I am setup to perform this procedure mobile for anyone that is located in Florida.
Anyway moving along, we start by opening the hood.
There are six bolts holding in the cabin filter, two up front:
And four are up near the wiper arms:
Cabin air filter removed:
Next up is removing the covers to the engine computer:
Push back the rubber tab:
And then pop the two tabs and lift the cover off:
Do the exact same for the opposite side:
Back on the passenger’s side, pull up on the two wire clips, then rotate the sensor towards the front of the car and push it out of the holder towards the center of the car:
Next up is the wire loop, it’s clipped to the engine bay cover. Use a small pick or flat head to depress the tabs and then pull towards the front of the car. The picture shows both wire looms removed.
Next up is removing the engine bay cover, slide the rubber tab off the plastic cover, then pull up on the hose clip, & do the same for the opposite side.
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Then remove the two bolts holding down the engine bay cover, and lift up on the cover in the middle and pull out.
Next up is the valve cover, its held on by 4 allen screws in each corner:
Remove the air intake, its held on by two torx, and the squeeze the top and bottom to expand the plastic over the ears on the filter box, pull back and lift up:
Squeeze and pull up to remove:
Remove the wire loom clips/rubber stays from the air filter box, loosen the front and rear turbo air intake clamps and pull the intakes back to remove from the air intake box:
The air filter box itself is held on by 3 friction fit rubber boots, two in the rear and one in front:
Air filter box removed:
Remove the diverter valves by twisting the grey rings and then pop of the diverter valves, and then remove the signal line from the intake manifold. Not shown in this sequence is removing the by-pass piping from the turbo intake pipes, but it is the same process as removing the diverters from the charge piping:
Next remove the clip from the sensor by carefully lifting up on the tab. I used a small flat head:
Now moving on the charge piping, pull up on the metal spring clip using a flat head – but do not remove it completely as shown, remove the torx, and loosen the clamp:
There’s a sensor on the charge piping, removal is exactly the same as the one before. I used a small flat head:
The charge piping is now free to remove:
Remove the vacuum line from the throttle body by depressing the top and bottom so the clip clears the ears:
Next up is removing the throttle body wire loom, small tip, push up from the bottom to release the clip that holds it to the throttle body:
This is the side of the clip
This is the bottom of the clip. Push up on this to release it:
Remove the wire harness clip from the intake manifold:
Next up is the wire harness bundle that is attached to the bottom of the intake manifold. Pull the plastic box off or remove the three torx screws:
Remove the hard plastic vacuum tubing from the master cylinder area for more room. Depress the white clip as shown, and you can remove the rubber line from the tee to remove the hard plastic vacuum line completely:
Pop the metal clip up off the sensor, and also undo the vacuum lines from the valve cover so you can access the intake manifold bolt behind that area:
Next remove the intake manifold nuts and single bolt and pull the intake manifold out. Be careful and double check you didn’t miss any connections:
Now the intake manifold is out, tape up the cylinder head immediately and stuff the turbo intake piping and intercooler piping:
Next split the wire loom plastic cover and set to the side, push the wire as close to the wiper area as possible:
Setup your walnut blasting tool. The complete tool is shown with both wands, and the BMW and MINI cooper vacuum attachments. With any pressurized vessel and blasting equipment, read and understand all the operating procedures and make sure all connections are tight. You can hurt yourself quickly and easily:
Fill the tool with crushed walnut:
Put the lid back on and make sure the o ring is in place correctly. Then tighten the eye bolts:
Connect the air line and turn the valve on to pressurize the unit
Shown below is a mock setup as if the vacuum attachment was on the cylinder head, then the vacuum attachment on the cylinder head, and then the wand inserted to the vacuum attachment. Be sure the valves on the cylinder you are working on are completely closed, in the pictures you will see my starter switch that I used to crank the motor over if the valves are not closed. When blasting work the wand all around to clean the intake runner and the back of the valves. Short bursts of walnut to bursts of air to clear spent walnut shell:
The next 5 shots are cylinders 2-6 in order, before I cleaned them. This car only has 20,000 miles since its last cleaning Cylinder one looked like cylinder 2 with regard to build-up:
The next two shots are after cleaning them with the tool. All the intake runners came out this clean:
I hate to be like a Haynes manual, and say assembly is the reverse of disassembly, but it is and I ran out of time. This is the car completely reassembled, and then a side shot of the car:
Enjoy you smooth as silk running engine.