Eccentric Shaft Sensor / Valve cover Gasket Replacement - DIY

[JThissell]

I haven't been around this forum for a while, but I just completed a major repair on my car and I'd like to share some of the experience in case someone else may find it useful.... first, none of this would have been possible without two major resources....the first is the www.pelicanparts.com tutorial on this repair:

http://www.pelicanparts.com/BMW/tech..._Replacing.htm

This is a pictorial description of what the problem is, what needs to be done, and gives a decent parts list. Also, they have a good aftermarket option for the Eccentric Shaft Sensor itself, made by OEM VDO. It's almost 50% cheaper than the BMW OE part.

The second was an unbelievable video of the DIY process:

https://www.youtube.com/watch?v=dV6slQsuZwk

This is an 1.5 hour video of most of the process, along with some great tips. I absolutely could not have done the job myself without this resource. Note that this video is of the repair done on an N51, which I think might be non-US. There are some differences between the N51 and N52 when it comes to this process. Also, not all N52's are created equal. The biggest differences seem to be that some have metal valve covers (aluminum?) and others have plastic. The metal valve cover has a metal valve cover gasket (it has a thin layer of rubber on it that forms the seal). The plastic valve covers have a flexible rubber gasket. Also some N52's have a system called "secondary air" which is a system with a compressor that pumps air into the exhaust when the engine is first started. It helps with emissions.

My car is an early 2006 325i, with an N52 engine. It has the metal valve cover and NO secondary air system.

My level of DIY experience: I did lots of work on my old E36, including brakes, spark plugs, and a full suspension (including new control arms and tie rods). Mostly just nuts and bolts stuff. Nothing this ambitious, and certainly nothing that would expose the inside of the engine.

So, what do you need?

PARTS:
Eccentric Shaft Sensor
Eccentric Shaft Sensor Seal (it's basically a very hard rubber coated metal grommet that forms the seal between the valve cover and the eccentric shaft sensor where it extends through the valve cover.)
Valve Cover Gasket
Secondary Air Gasket (even if you don't have the Secondary Air System, there is a blank plate attached to the side of the engine, and the gasket can leak. Might as well change it while you are in there. The gasket cost under $5 I think.)
Valve Cover Gasket Bolt Kit (it's 18 bolts...the valve cover bolts are single use, so you replace them all)
Spark Plugs (mine were a mess due to the engine running poorly because of the bad sensor)
NOTE: In the video, the guy says the valve cover should be replaced because it can crack. I'm pretty sure that's because the car he's working on has the plastic valve cover. I doubt the metal ones need to be replaced.

TOOLS/SUPPLIES:
Big Flat Head screw driver
Small Flat Head screw driver
Big philips screw driver
Ratchet
Assorted socket/ratchet Extensions
Assorted Adapters (big to small, etc.)
10mm deep socket
SWIVEL connectors for sockets (I CANNOT STRESS THIS ENOUGH. THIS JOB IS ABSOLUTELY IMPOSSIBLE WITHOUT SWIVELS)
Full Metric Socket Set (Heavy use of the 8mm and 10mm, but also used several others)
External Torx Sockets (Note: these are hard to find. you can't just roll into Sears and pick them up. I did, however, find a universal socket set that does 6 different types of bolts at Lowes.)
Helps to have a Screwdriver handle on which you can mount sockets. It's much faster to get bolts started with this before you put the ratchet on it)
Electrical Tape
Brake Cleaner (common brand is "Brake Kleen" if I'm not mistaken)
MAF Sensor Cleaner (I suppose any electrical contact cleaner will do)
Old dish washing hand brush
Old tooth brush
Q-tips (lots of them)
Paper Towels (lots of them)
Rags (Lots of them)
Small pry bar (mini crowbar)
Quart of motor oil (actually a couple teaspoons is plenty. I just cracked a new bottle.)
3M Scotchbrite pads (Get the "non-scratch" ones from Target, for example. The regular ones are too abrasive.)
Long-handled gasket scraper
Razor Blade (helps to have this mounted in a holder)
Impact Wrench - optional (I only used it for one bolt. And I let out a Tim Allen grunt after I removed the stubborn thing.)
Bungee Cord(s)
Flashlight
LED Headlight (invaluable when you're burning the midnight oil)
Unusually warm December weather.

The process:
1. REMOVE THE COWL AND STRUT BRACES:
The plastic pieces at the base of the windshield come off pretty easily. The video linked above shows this very well, so I won't spend much time on it. Also, the bolt attaching the drivers side strut brace is the only bolt I used the impact wrench for.

2. REMOVE THE PLASTIC ENGINE VANITY COVER:
Again, the video covers this well.

3. STOP!!! TAKE PICTURES!!!! TRUST ME!!!
The wiring under there is kind of spaghetti, and the rest of the repair is going to take you so long, you'll never remember what the thing looks like assembled.

4. NOTE:
The video mentions that you need to cut the flange at the edge of the ECU box, and to loosen certain parts of the cowl to be able to lift them up higher. I didn't have to do either. YMMV.

5. DISCONNECT WIRES:
On the passenger side of the engine, there is a long black plastic rail that holds the wires for the spark plug coils. It has a couple ground wires on the bolts that connect it to the valve cover. Take them out. (IMPORTANT NOTE: Put all nuts and bolts for a given item together and label them. I used painters tape to tape them together and labeled it..."COWL" "GROUNDS" "COOLANT RESERVOIR" etc.)

6. OPEN THE ECU BOX:
The video shows this well. This allows you to lift up some of the cables, which allows you to move the spark plug wiring rail out of the way. Note: the cable housing that runs from back of the spark plug wiring rail around the rear of the engine seems way too short, but it's hooked on a cable management hook somewhere on the back of the engine. once you unhook it, it has plenty of slack to lift up that rail.

7. DISCONNECT THE CRANKCASE BREATHER HOSE:
The video shows what this is pretty well. However, it cuts away, and the guy comes back and says....ah yeah, that was a pain, took a while. Mine went quick because I took a gamble and won. In the video he shows that you pinch the connector on opposite sides to unlatch it. However, this is hard to do. What happens is you pinch opposing sides, and the two sides at 90 degrees to your fingers bow outward, releasing the catches. Problem is, the connector doesn't always cooperate, it's on the back of the engine, you can't see it well, and you can't fit your hands back there. I was able to feel one side come unhooked, but not the other. So I took a flat head screw driver and pried the other side outward. Pop....off it came.

8. DISCONNECT THE COOLANT RESERVOIR:
Video shows the hose connection release. Flat head screwdriver does this with ease. I also unscrewed the two bolts that hold the reservoir to the frame, and bungeed it to the front of the engine bay to make more room. Note, there is a rubbery thing at the bottom of the reservoir with what looks like a tube extending into it. It kind of looks like a coolant tube. It's not. it's just a cushioned mount for the bottom of the reservoir. Just pull the reservoir upward and it pops out of the rubber grommet.

9. DISCONNECT MORE WIRES:
There are two wires attached to the frame right next to the ECU box. One is the opposite end of one of the grounds that you've already disconnected from the spark plug rail. The other seems to come from the ECU box, I think. Take off the nut, and pull off both wires. Set the ground aside. Having a picture of this assembled helped me figure out where this ground goes when I put it all back together. There are several places you could attach it over there.
Also, there is a power wire that attaches between the battery terminal and the ECU box. There is a little black plastic shield covering the terminal where the wire is attached. The shield pries off pretty easily, and you can just unscrew the nut to free the cable. Tape over the end of the wire with electrical tape. Put the shield back over the terminal.

10. TAKE APART THE FUEL DELIVERY ASSEMBLY:
The video covers this well. The fuel assembly sits between the manifold and the valve cover. The hardest part of this is loosening the small clips that hold the 6 electrical connectors onto the fuel injection assembly. The video shows it well. I used a flat head screwdriver, whereas the guy in the video used a 90 degree pick. Not sure the pick would have been any better, but I didn't have one. You shouldn't have to pull out the fuel injectors themselves, just detach the electronics (they extend over the valve cover).

11. DETACH THE SPARK PLUG COIL WIRES:
This is shown well in the video. It's easy, but only if you see how the connectors work. Disconnect the wire connectors, then pull the coils out of the holes.

12. REMOVE THE VALVETRONIC MOTOR:
The video covers this well. This is the 5 inch long, transversely mounted cylinder that attaches to the passenger side of the valve cover. (Actually it attaches to the engine THROUGH the valve cover) Taking this off looks easy because it's just three small bolts, but taking off the bolts in the right sequence is important. There is spring tension on the valvetronic motor. First, take a 4mm allen wrench and turn the shaft in the valvetronic motor clockwise to release some of the tension. (Shown well in the video) Then, loosen the top two bolts about half way off. Then take off the one bottom bolt mounting the motor to the valve cover. The motor will pop out and be caught by the two top bolts. Then loosen the two top bolts a little at a time and ease the motor out.

13. MAKE SPACE TO GET THE VALVE COVER OUT:
Bungees help. I bungeed the hoses and wires that extend across the top of the motor, and hooked the bungees to the windshield wiper.

14. LOOSEN THE VALVE COVER BOLTS:
SWIVELS!!!!!! Incidentally, the valve cover bolts are external torx bolts, but I was able to use an 8mm hex head socket just fine. They are small, and are not super tight.

15. BREAK THE VALVE COVER LOOSE:
Video shows this well. Those of you with a plastic valve cover, I would be careful with this. I didn't like the idea of knocking the valve cover like the guy does in the video. I tried it gently, and then chickened out. I used the small, thin pry bar and tapped it gently with a hammer and it slid right under the valve cover and popped it off.

16. PULL OFF THE VALVE COVER:
See video. Note: In the video, the guy pulls off 6 metal sleeves that form the spark plug holes. He says that they are single use and to replace them. This seems to only be for the plastic valve covers. The metal sleeves were built into my metal valve cover.

17. REPLACE THE ECCENTRIC SHAFT SENSOR:
See video. Note, putting the bolts the way the video recommends didn't exactly work for me. I just kept adjusting until the new sensor went into place.

18. REPLACE SPARK PLUGS:
HEY, YOU'RE IN THERE ANYWAY, RIGHT?! At this point, it's an extra 10 minutes. The dealer wants 3 hours to do spark plugs. First time, I did it in 30 minutes start to finish. Here, it's even faster because you have already taken off the cowl, vanity cover, and the coils.

19. CLEAN EVERYTHING:
The valve cover may be a mess inside. This is where the brushes, Q-tips, and rags come in. Brake clean helps here too.

20. CLEAN THE GASKET MOUNTING SURFACES.
See video. Additional notes: The rubber-coated metal gaskets pop off in one piece. No problem. So the surfaces should be pretty clean. They still need a bit of prep, though. The video shows this well. Again, I used the NON-SCRATCH version of the 3M Scotchbrite. I used a little Mobil 1 motor oil as a lubricant and solvent with the Scotchbrite. I also used a razorblade for stubborn buildup. Then use the brake cleaner to clean it. The brake cleaner evaporates very quickly (alcohol?) so it leaves the surface clean, oil-free, and dry. You need to do this on both the engine and the valve cover surfaces. also, clean the surfaces of the valvetronic motor and the surface of the engine on which it is mounted.

21. REPLACE THE SECONDARY AIR GASKET:
Remove the blank plate, use the gasket scraper to pop off the gasket....it's a paper-covered metal gasket. Prep the gasket mounting surfaces as above. If you don't have secondary air, just put it back together now. It won't be in the way of putting everything back together. If you DO have secondary air, you'll probably have to wait.

22. REPLACE THE ECCENTRIC SHAFT SENSOR SEAL:
It looks like a simple rubber grommet, but it's a rubber-coated metal seal, so it's very rigid. You can't just push it out from the inside of the valve cover. it's better to just pry it off using a flathead screwdriver. There are little notches that help you do this. The new one goes in pretty easily with finger pressure.

23. PUT THE VALVE COVER GASKET ON:
This is NOT covered in the video. I believe in the video, the gasket is mounted on the valve cover first, and then the valve cover is mounted onto the engine. Not so for the metal valve covers and rubber-coated metal gaskets. There are 4 small cylindrical extensions around 4 of the bolt holes on the engine. They help align the gasket and hold it in place when you're mounting the valve cover. The center portion of the gasket (i.e., around the spark plugs) also has tabs (at least mine did) that prevent you from mounting it backwards. IMPORTANT NOTE: You don't need RTV (gasket sealer), and you don't need hi-tack spray like you might with a rubber gasket. The metal gaskets have a very thin rubber coating, and then three raised rubber ribs on each side. These form the sealing elements. It's a good design.

24. MOUNT THE VALVE COVER:
When putting in the bolts, note that they don't ever snug up the way they would if you were joining two incompressible surfaces (e.g., metal to metal). Instead, you can keep turning the bolts with minimal pressure. However, if you keep going, you'll snap the bolt. (Ask me how I know). If you have a torque wrench, definitely use it. If you don't, recalibrate your use of the traditional German torque spec...."guttentite."

25. REINSTALL THE VALVETRONIC MOTOR:
Don't forget to use the new gasket.

26. THE REST IS PRETTY MUCH THE REVERSE OF REMOVAL. One tip I would say would be to really be sure you have the fuel injector wires situated they way you want them before reconnecting the electrical unit. Remember those clips were a pain to remove, so you don't want to have to do those again. Use the pictures you took after removing the vanity cover.

27. ENJOY SAVING $1000+

This took me multiple days to complete. I can see why the dealer wants $1500+ to do it. Of course, I could do it again right now in about half the time.

I hope this helps someone. From what I've seen in my online research, this is a really common issue.

[alfredlop]

Hi , My car is 528Xi and i notice a small leak by the eccentric sensor the car its noting wrong its working fine its any way to just change the O ring or seal?

[ithaca]

JThissell,

Nice post! I can confirm that the dealer will charge $$$. I recently had the bad luck to be out of town and could not get the car started. I'll update one of my threads (where I first posted symptoms) with the details. But it was the eccentric shaft sensor, valve cover gasket replacement, and recoding which totaled $1800. I knew of the Pelican Parts thread, but your notes are invaluable.

[Mferko9988]

PLEASE HELP!! For some reason I am having a hell of a time getting the Eccentric Shaft Sensor Seal in without destroying it....also I have the aluminum valve cover not the plastic