BMW E46 3-Series DIY: Spark Plug Replacement
This DIY article will help you successfully change the Spark Plugs in the E46 3-Series. This was done on a 325xi so there might be a few variations between the different models, but all should be closely related.
This is also a very good time to do your Valve Cover Gasket if it is time to have that done. If you are looking for the Valve Cover Gasket DIY please follow the link below:
E46 Valve Cover Gasket DIY
Flat Head Screwdriver
3/4 Breaker Bar
3/4 Extensions (6"+)
5/8" Spark Plug Socket
TORX 30 Socket
Optional: Permatex Anti-Seize
OEM Spark Plugs (6): 64 31 9 071 935
First thing we want to do is remove the cabin filter housing so give us a bit more room to change the spark plugs
There are 3 securing tabs holding the cabin filter cover on. They are outlined in the picture below
To release the tabs, simply twist them counter-clockwise
Here is a shot of the tabs in the released position
Pull the cover off the reveal the cabin filter
The cabin filter just sits in the housing. Simply pull it out to remove. Note the orientation so you put the new one back in correctly
Removing the cabin filter will reveal four (4) TORX30 bolts holding the carbin filter housing in place. Grab your 3/4 Ratchet and loosen these up. They will not come out from the housing, but will become loose as to where you can remove the panel
Below are all four bolts outlined for your convenience
Before we remove the cabin filter housing let's take the battery line and the coil pack harness line out of the front holder. These wires are secured in this plastic housing. Simply pop the four (4) clips as shown below to open the compartment
Remove the two wires (coil harness on top / battery line on bottom)
We can now remove the cabin filter housing by pulling forward and placing it out of the way.
Let's get the battery line out of the way. Pop the cover shown below next to the passenger shock tower to reveal the 19mm bolt holding it down
Grab your ratchet and 19mm socket and remove it
Place the 19mm bolt back on the screw to ensure you don't misplace it. You can now move the line out of the way
Now we can work on removing the engine dressing covers. Grab a flathead and locate the two caps pointed out below. By popping these off you will reveal the two 10mm bolts holding the cover to the valve cover.
Remove the oil fill cap by rotating counter-clockwise
Grab your 10mm socket and remove the two bolts holding the engine dressing on
We can now pull the cover off and place it out of the way.
Same thing for the top cover. Remove the two covers shown below and remove the two (2) 10mm bolts. Then pull the engine cover from the engine bay
By now you should be looking at something like this
Next step is to remove the coil packs.
Note: I believe some of the early model E46 coil packs might be secured to the valve cover via bolt design. If so you can easily enough just unbolt them and pull them free from the valve cover
First step to the coil pack removal is to release the coil pack harness from the coil pack itself. This can be done by sliding the locking mechanism upward as shown below
The with lock mechanism released you can grab the connector and pull away from the coil pack. Repeat this step for all 6 coil packs.
Here is a shot of the connector free from the coil pack
The coil packs are suctioned into the cylinder head so i found the best way to remove them was with a small extension. Grab your extension and slide it through the release connector as shown below. Apply and equal amount of pressure on each side to prevent snapping it. Pull upward gently to remove the coil pack
With the coil pack loose you can slide it out of the cylinder head
Here is a shot of valve cover with all of the coil packs removed
Shot of the plug in the cylinder
Grab your 5/8" spark plug socket and a long extension for your breaker bar.
Insert the socket into the cylinder head and remove the spark plug
Here is a shot of the plug removed
Comparison of the new plug with the old plug. These plugs had 51K miles on them
Time to throw the new plugs in. I know people have mixed feelings on the anti-seize paste, but i recommend it as i use it on all of my cars and i never had a problem. I use the Permatex Anti-Seize Lubricant. You can get this stuff pretty much anywhere
Lightly apply the Anti-Seize to the threads of the spark plug
Drop the new plugs into the cylinders
Grab your spark plug socket, extension and torque wrench to tighten the spark plugs back up. Tighten to the torque specifications below
Torque Specs: 23 ft/lbs
With your plugs all tightened back up you can begin the re-assembly in reverse order. I highly recommend doing the valve cover gasket at this time since you are half-way through the steps required to change it at this point.
Hope this article has helped and motivated you guys to continue doing your own maintenance. Any questions please feel free to ask.
Thanks for the diy
Why do you remove the vent tube from the valve cover?
Can you do this without removing the cabin air filter housing? Is it just a little more convenient with it out of the way or what?
I would be a bit concerned about removing the positive battery cable and letting it flap around like that. I'd have to check the wiring to be sure but that's connected directly to the positive battery terminal (via that main fuse). If it touches the grounded/earthed both you will short the battery.
If you're going to disconnect the positive, disconnect the negative first.
I would skip those steps and have the correct ratchet attachments available to fit in the tighter space. Much less work.
Cool, thank you!!
I can't imagine doing the spark plugs without removing the cabin air filter housing... there's almost no room above cylinders 5/6 with that thing in the way. I'd rather just remove the 4 screws and have all the room I want
I wouldn't bother removing the positive terminal though.
I ve changed the old NGK plugs from my 330xi for Boch Platinium and now I ve error code in all 6 cilinders lol didnt ve time to see in deep the issue but i will do some checking this weekend
Just did this tonight on my 2002 325i with some NGK replacements. Less than 60,000 miles, but I could definitely tell a difference afterwards. I have only owned this for a couple months and I believe the previous owner only drove it on short trips (hence the low miles). The old plugs were nice and brown/black.
older e46 coil packs
the older coil packs are bolted on. ease-peasie to remove, the locking mechanisms are slightly different too. the pic shows the first coil pack removed, and the second locking mechanism unlocked.
thanks for the DIY write-up...
oh, one other thing, I was going to attempt to use regular NGK Platnium... but they're >3mm (>0.125in) longer than the OEM... didn't want to chance it, so went with OEM.
Nice write-up! Forgive me if I just missed this but is there some procedure for gapping the new plugs? ...or do you just install them as they come out of the box?
+1 on the anti-sieze.
A tip for others scared to use it: Don't gob it on & leave the 1st few threads near the tip free of the stuff. You only need a tiny itty bitty bit for it to work as intended. I put a very light strip of the stuff perpendicular to the threads while keeping it off the 1st few threads & away from the crush ring. Torque to 16 ft-lb with a torque wrench (emphasize on using a torque wrench). NGK has their own recommendation for torquing down without a torque wrench but doing their procedure caused loose plugs in my E36 M3 on 5 cylinders when I did it; caused a nasty tapping/popping sound after a few thousand miles which is horrible on the head threads when this happens.
When I removed the original factory NGK plugs on my 325i with 100K miles, cylinders 4 & 5 were down right scary to remove. I had to use a breaker bar to get them to budge & even after breaking loose I had to use a ton of force & it made a screeching noise with every turn of the ratchet; engine was cold as well. The threads on these two plugs had a bit of aluminum 'dusting' on the rusty threads when removed; not good... Anti-seize when used properly will help prevent further thread damage as I won't have this problem again when removing the plugs.
hi your car looks good any suggestion to keep my car pretty i haven't done any buffing or retouching to my car 330ci but i know its about time...btw...the very first successful work i did for my car is replacing the front splash panel and installing the ambient temperature sensor
Big thanks to OP. I just did this and the VCG and it was quite easy thanks to your post. :thumbsup:
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