[Radioactive]

Replace the plugs today with OEM plugs. About $20 a piece from BMW. It took about 1.5 hrs to complete taking a first timers time. Since this engine does not have a turbo I thought I'd post how I did it. If you follow this and your car screws up; it's your responsibility.

The plugs are NGK's and the model number is highlighted in the photo of the box, as well as the BMW part number. As you can see in the photo the torque is 30 Nm +/- 3.

To remove the middle black plastic cowling remove the rubber stripping, unscrew the two 30T torx screws and unclip the wire holders. Pull the cowling to the front to remove. That is all the cowling that needs to be removed. No need to remove windshield wipers or other cowling.

The engine cover has four 5mm hex(allen) bolts; two the front and two in the rear. Space is limited in the rear so I used an "L" shaped wrench. Pull the cover to to right (passenger side) and forward since there is a plastic connector under the rear left portion of the cover.

Plug tubes are now exposed. Flip up the tube wire clips, remove wire connector, remove tube, remove old plug. Then install/torque new plug. Install tube, wire connector and secure connector with clip.

Plugs five and six are a little more difficult. I first removed the tube on five and replaced the plug. I did not install the tube yet, so I could have more room to work on plug six. Then I unbolted the light silver bracket, move/unclipped any wires in the way and removed/replaced the plug and tube on number six. I then came back to number five and installed the tube and wiring.

After all the plugs were installed, I then installed the silver bracket and then installed the cover and cowling in reverse order of above.

[///Mposter]

You were busy this weekend!

[Asianoak]

I just did this on my '11 28i and it made a HUGE difference. I didn't realize the service interval had changed so I was still going off the old 100k recommendation and waited till 95k to do it. The vehicle accelerates smoother now, no weird stutter off the line and gas mileage is up. I did this along with the serpentine belt and tensioner pulley, as well as the intake filter and cabin filters. Also did the front and rear differential fluids a few weeks back.

If you're waiting to do yours trust me... do them at 60k as recommended. You might not experience as drastic a change as I did, but you'll also save yourself from terrible gas mileage and other side effects.

[pokerface]

on our N52 we replaced coil packs and spark plugs at 60,000 KMS. Big improvement. Not to mention one of them was misfiring.

Curiously we recently did the same service on our N20 at 58,000kms and no noticeable differences.

[Bilbofraggins]

My routine is plugs at specified intervals...a measley 50,000 km on my E71... and coils... the set when one fails...

On an E90 we went over 10 years doing that.... and only recently did coils... which basically lined up with a plug change anyway.

[pokerface]

Originally Posted by pokerface

on our N52 we replaced coil packs and spark plugs at 60,000 KMS. Big improvement. Not to mention one of them was misfiring.

Curiously we recently did the same service on our N20 at 58,000kms and no noticeable differences.

bump - N52 update: 105,000kms (3.5 years later) we are getting misfires again.. Engine sounds like shit and running rough, it's almost as if one cylinder is not firing at all. VS previously it would only CEL if accelerating more than gently. We'll be changing plugs and coilpacks shortly. Seems like we're doing this like clockwork!

[bmkman]

Originally Posted by pokerface

bump - N52 update: 105,000kms (3.5 years later) we are getting misfires again.. Engine sounds like shit and running rough, it's almost as if one cylinder is not firing at all. VS previously it would only CEL if accelerating more than gently. We'll be changing plugs and coilpacks shortly. Seems like we're doing this like clockwork!

I just tried to change my plugs but I notices they did not loosen easily. Do you have any tips? (I just tried plug 1 and 2) Did you use any special tools etc.? I am thinking to get a lockable extension because my sparkplug socket extension loosened from the extension I have because sparkplug socket was stuck to the plug. I had to carefully click in the extension back into the sparkplug socket to fish it out.

I am replacing the plugs at 75k kms, this probably overdue but the dealer never suggested to change it. I recently had misfire on bank 4 so I replaced the ignition coil and that seemed to fix the problem.

[Wgosma]

Might be your plug socket wall thickness is too large a diameter; perhaps socket is binding between wall/plug?- seems I read a while ago about a recommendation to use "thin walled" plug socket is best for N52 motors. Something like this: https://www.ecstuning.com/b-schwaben...RoCaVQQAvD_BwE

[HPR]

A 14 mm, 12 point thin wall socket is required. If you search BMW thin wall spark plug socket you should be presented with a number of choices. Had to purchase one when changing plugs on my N55. Available on Amazon or most places where automotive tools are sold.

[bmkman]

Thanks Wgosma and HPR...the 14mm "Thin Walled" deep socket is on order.

I read a few posts from various BMW sites but noone mentioned the "Thin Walled" socket. My job is on hold until my wife's new car arrives...my wife is now suspicious of my work and she doesn't want to be without a car.

[christianherc]

Hate to bring up a dead post, does anyone have the cylinder numbers marked off ?

i have a cylinder 5 misfire and id like to try and replace the plug and coil before I take it somewhere.