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Discussion Starter · #1 ·
I did a change today and there were a couple of things I figured out that made it easier.

1. Get a 1/4" drive stubby flex-head ratchet. The one I picked up is about 4 inches long, and it made the job SO much easier!

2. All of the screws and nuts for the cover, the electrical harness retainers and the ignition coils are 10mm. It's the only size socket you need for that part of the job. You will find that having a deep socket and a regular socket is helpful. If the deep socket is a 3/8 drive with a 3/8 to 1/4 drive adapter, that's even better.

3. A standard "small" spark plug socket works fine. You need one with a rubber insert that will hold a plug and not drop it, and that won't come out when you pull it off the back of the plug after installation.

4. You need to have a long extension for the spark plug socket - I used a 9" and a 12" together. Use the "wobble" kind from Craftsman - you can't get a straight shot at any of the plugs, but the angles you need are small.

5. The existing plugs are tight. Use a long handled ratchet or breaker bar on the long extension to crack them loose. They'll unscrew easily after that.

6. Use a torque wrench to tighten the new plugs. 30 N-M is the spec, and if you use BMW spark plugs, the torque is on the box.

7. Do the driver's side first. It's the most challenging (it's not that hard, just tedious) and so you should get it out of the way first.

Disassembly instructions:

Starting on the driver's side, pop the cabin air filter box off (I won't provide instructions, but it's easy - same process you use to gain access to the brake master cylinder). Rotate the cabin air intake air snorkel toward the engine to make a little more room. Don't remove the snorkel, you don't need to.

Undo the two cap nuts that hold the cover on. This will be your first opportunity to use the stubby 1/4 drive ratchet. The rubber bushings around the nuts and the washers are all separate and loose, but they stick together from the heat. Don't drop them when you take it apart. Pull the cover loose from it's gasket and slide it forward and out.

Undo the two nuts that hold the wiring harness for the coils. I cracked withm with the stubby ratched and a socket, and then used the 3/8 drive deep socket as a nut-driver to remove the nuts. Using the socket allows you to turn the nuts without the risk of dropping them.

Pull the harness away from its studs, and then remove all 8 nuts that hold the coils in place. Again, each one will have a different challenge because of the cramped quarters. I used the stubby ratchet and a socket to crack them, and then used the deep socket as a hand tool to remove them.

Once the coils are loose, but still in place, use a screwdriver blade to pop the shiny metal brackets on the coils up. Slip it into the slot below the bracket and twist gently - the brackets lock the connectors, so pull the brackets up as far as they'll come (about 1/2 inch or so) and then gently pull or push the black connector off toward the rear of the car. They're EASY to take apart, so you shouldn't be struggling with them. Starting from the front of the engine (Cylinder 5) undo the connectors and grab the coils under the "ears" that go over the studs, and pull them out - again, you can be gentle because they come out quite easily. I took all four out and set them aside.

At this point, you're looking at the four spark plugs deep (really deep - remember the 21 inch extension?) in their openings in the cylinder head. Using the long extension, remove the old plugs and screw in the new ones. Torque to 30 newton meters. This is the easiest part of the job!

Once the plugs are changed, put it back together in the reverse order to taking it apart. Install the coils from the back of the engine to the front. The way I did it, I slipped the coil back onto its studs and did up the electrical connection. The push down on the bracket to lock the electrical connection also seats the coil onto the top of the plug.

Once all the coils are in and hooked up, put all the nuts back on the coils and tighten them. Then reposition the wiring harness and install the two nuts that hold it in place.

With all the wiring, coils and plugs back where they belong, it's time to put the outer cover back on.

On the driver's side, but not the passenger's side, you will have to wrestle with the rubber sealing boot where the wiring harness enters the outer cover at the back near the firewall. On the drivers side, the brake lines keep the cover close to the head, and you have to coax the rubber boot, which has a slot in it, to pop into the corresponding opening in the cover. The natural tendency is for the "top" to slip in nicely, and for the bottom to firmly resist going back into place. The trick is to push the top of the boot back and seat the "bottom" and then wiggle the top forward into place. That works!

On the passenger side, there's enough room to just pull the cover back and slip it over the boot. No struggling required.

Anyway, once you have the boot properly seated in the cover, put the two cover cap nuts back on and tighten them. They bottom, so torque them gently after they stop turning and you're done.

Now do the other side. There's more room on the passenger's side, so it goes quicker with less contortions.

Total time - 1.5 to 2 hours.
 

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I think this one should be in the FAQ.
 

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Excellent write-up. I agree, it is definitely FAQ quality!

I want to add this:

1. Remove snorkels.

It can be very difficult to get the rubber grommets found at the rear of the spark plug covers in thier places during reassembly, unless one completely removes the snorkels. Doing this right at the beginning makes more room for working too, and on the whole saves time.

When removing the snorkels first take a flashlight and get a good look at how those are seated against the wall towards the passenger compartment.

2. Pay attention to what spark plug comes from what cylinder, and save the old spark plugs.

The cylinders are numbered from 1 to 8 as follows:

Front of car
Left side - right side
Cylinder Bank 2 - Cyliner Bank 1

5 - 1
6 - 2
7 - 3
8 - 4

Rear of car

The reason for keeping track of the old spark-plugs is it can later provide important information to a person who knows how to "read" spark-plugs, if the engine ever develops a problem.

Also it is good practice to put the coils back in the same places those were.

Cheers,

David
 

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Useful post - thanks. I just did mine. It certainly helped the driveability when cold (no juddering/kangaroo-ing).

Can I add that you don't need to remove the coils. Just undo the nuts on the coils and the extra bar holding the earth wires. Then, gently pull the coils away from the head until the pop off the spark plugs. Twist them slightly and lay them back in place, but not over the spark plugs. There should be plenty of room to get at the spark plugs to remove/replace them now.
The whole process took me under an hour. Fiddliest job was getting the rubber seal at the rear of the cover to stay where it's meant to be. I noticed it hadn't been put back in place when it had rocker gaskets changed under warranty last year...

Good luck!

Simon
 

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Discussion Starter · #5 · (Edited)
Thanks all for the appreciative noises - it's an easy job, but there are few lessons that I learned on my first try that make it easier for the rest of the DIY types like me.

The LH (driver's side) rubber boot is the trickiest part, for sure.

On my first try, I did it the obvious way, I put the boot into the opening on the cover (top and sides) as I was putting the cover in place. Problem was, it would go in fine on the cover, but I couldn't get the bottom edge against the cylinder head to go in after the cover was in place. After a few tries, I changed my approach.

What I did was pull the boot into place and hook it onto the cylinder head (the lower fixed edge) first, then as I gently put the cover in place, without dislodging the lower edge of the boot, I just pulled the sides and top of the boot "forward" into the opening. It just popped right in. Being right-handed helps, I suppose.

On the passenger's side, the same approach works - just put the edge against the head in place first, then slide the cover down onto the slot on the boot. No contortions required because there's room to do it this way.

This approach works equally well with the snorkels in or the snorkels out.

Cheers
JJ
 

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jaj said:
I did a change today and there were a couple of things I figured out that made it easier...

1. Get a 1/4" drive stubby flex-head ratchet. The one I picked up is about 4 inches long, and it made the job SO much easier!

4. You need to have a long extension for the spark plug socket - I used a 9" and a 12" together. Use the "wobble" kind from Craftsman - you can't get a straight shot at any of the plugs, but the angles you need are small.
Wondering if I'd be better off getting a universal joint and then use my existing 1/4" rachet. Also, the universal joint could serve as a "wobble" when you combine two regular extensions. I could save money by not having to buy a flex head rachet. Would you think the universal joint works for this application?
 

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Discussion Starter · #7 ·
The 1/4" stubby flex ratchet is for all the 10mm head screws that hold things together. It makes the job easier but is not required - a regular ratchet will work fine.

The 21" extension is 3/8" for the spark plug socket - a universal joint would work but it would be frustrating because you couldn't guide the socket onto the spark plugs easily. As with the 1/4 stubby ratchet, it's handy but not essential. Use what you have - it'll be fine!

Cheers
JJ
 

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jaj said:
The 1/4" stubby flex ratchet is for all the 10mm head screws that hold things together. It makes the job easier but is not required - a regular ratchet will work fine.

The 21" extension is 3/8" for the spark plug socket - a universal joint would work but it would be frustrating because you couldn't guide the socket onto the spark plugs easily. As with the 1/4 stubby ratchet, it's handy but not essential. Use what you have - it'll be fine!

Cheers
JJ
JJ - Thanks

I have quite a few extentions to get me to 21". They're hybrid wobble/fixed, but they're 1/2". I have a 3/8" to 1/2" adapter for the spark plug socket. I haven't opened it up yet, but do you remember if 1/2" extensions will fit. I'm guessing it would, but it would make it hard to guide the spark plug through.
 

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Excellent post JJ!!

I was going to change the plugs this weekend :)

Are there many choices for spark plugs?

I was going to get them from the main dealer but if there is a better option out there I would rather do that.

Cheers,

Richie.
 

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jaj said:
Disassembly instructions:
#2 Undo the two cap nuts that hold the cover on. This will be your first opportunity to use the stubby 1/4 drive ratchet. The rubber bushings around the nuts and the washers are all separate and loose, but they stick together from the heat. Don't drop them when you take it apart. Pull the cover loose from it's gasket and slide it forward and out...

#5 Once the coils are loose, but still in place, use a screwdriver blade to pop the shiny metal brackets on the coils up. Slip it into the slot below the bracket and twist gently - the brackets lock the connectors, so pull the brackets up as far as they'll come (about 1/2 inch or so) and then gently pull or push the black connector off toward the rear of the car. They're EASY to take apart, so you shouldn't be struggling with them. Starting from the front of the engine (Cylinder 5) undo the connectors and grab the coils under the "ears" that go over the studs, and pull them out - again, you can be gentle because they come out quite easily. I took all four out and set them aside.

#6 At this point, you're looking at the four spark plugs deep (really deep - remember the 21 inch extension?) in their openings in the cylinder head. Using the long extension, remove the old plugs and screw in the new ones. Torque to 30 newton meters. This is the easiest part of the job!
Here are pictures to #2, #5 and #6. The universal joint gave me more flexiblilty than the wobble extension; I did not need to remove the air filter box.

Edit:
The spark plug socket, two 6" regular extensions, one 3" regular extension and a universal joint to join the 6" extensions.
 

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The cylinders are numbered from 1 to 8 as follows:

Front of car
Left side - right side
Cylinder Bank 2 - Cyliner Bank 1

5 - 1
6 - 2
7 - 3
8 - 4

Rear of car
Can someone please simplify this? I'm trying to understand this but it doesn't make sense though I really need to know how to identify which cylinders are which... thanks!
 

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I'll exhibit my artistry. You are sitting next to cylinder #1. The passenger sits next to cylinder #5.
Darn it now I'm confused :eek:oohhh: I'm pretty sure 1-4 are on the passenger side and 5-8 are on the driver's side... very nice picture though, let's get some more opinions on this...
 

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Darn it now I'm confused :eek:oohhh: I'm pretty sure 1-4 are on the passenger side and 5-8 are on the driver's side... very nice picture though, let's get some more opinions on this...
Yeah - reverse it :haha:...
Wiki has something else. But if I can remember right, there's a real m5 pic and discusson somewhere on this forum.
http://en.wikipedia.org/wiki/Firing_order

Edit: I'd say listen to David. He's been around the block awhile...
 

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Yeah - reverse it :haha:...
Wiki has something else. But if I can remember right, there's a real m5 pic and discusson somewhere on this forum.
http://en.wikipedia.org/wiki/Firing_order

Edit: I'd say listen to David. He's been around the block awhile...
that agrees exactly with what I've been seeing and that pic makes perfect sense, thank you for that, just what I needed
 

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Good stuff, old post brought back from the dead, but I am planning on changing my plugs so it is good to go.
 

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Having never done spark plugs on any car before, I am glad that I decided to get my mechanic friend to do them for me while I watched. He knocked the job out in an hour and a half! But I could tell that I would have either gotten stuck or broken something had I attempted to do this myself, without experience. Now that I've seen this done, next time I might be brave enough to attempt this myself. :) P.S. I went with Bosch Fusion spark plugs part #4503.
 

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I assume the $7 BKR6EQUP part from Amazon.com is the same as the part from the dealer?

Thanks for the helpful info. I will be doing this in the next few weeks.
 

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I assume the $7 BKR6EQUP part from Amazon.com is the same as the part from the dealer?
It won't say "BMW" on it.....but they're what I put in today. I found removing the cabin air filters and connector at the firewall made getting the big aluminum cover on much easier.....especially at the grey/white boot near the firewall end of the coil bank......and it only takes a minute to remove the CAF housing at the firewall.....twist just a tad counterclockwise to loosen.

Did the fuel filter this weekend too.....overall.... more even and smoother going through the gears now.

Cheers,
~E
 
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