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Valve Cover Replacement
 
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Pelican Technical Article:

Valve Cover Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$50

Talent:

****

Tools:

Set of sockets, wrenches, screwdrivers

Applicable Models:

BMW Z3 (1996-02)

Parts Required:

Valve cover gasket, valve cover fastener sealing grommets, RTV (silicone sealant)

Hot Tip:

Work with a cool engine.

Performance Gain:

Cleaner engine bay

Complementary Modification:

Change engine oil and filter. Change spark plugs

The BMW Z3 engine cylinder head is covered with an aluminum or plastic cylinder head cover, also known as the valve cover. The ignition coils are bolted to the top surface of the valve cover. The spark plugs are installed in deep wells in the valve cover, one spark plug beneath each ignition coil. The electrical harness to the ignition coils is routed along the top of the valve cover as well. The crankcase breather hose is clipped to the front left of the valve cover. 

The valve cover gasket is one of the most common places to have an oil leak on your BMW Z3. If you have an oil leak down the exhaust side or front of your engine, start at the top and replace the valve cover gasket. When the valve cover gasket leaks, it can create quite a mess and seem much worse than it is. 

On 4-cylinder models: Engine oil can also leak into the spark plug holes in the cylinder head, contaminating the wires. You will have to repair the oil leak and replace the ignition wires to prevent future problems with the ignition system. Inspect the valve cover once the gasket has been removed. 

On 6-cylinder models: Engine oil can also leak into the spark plug holes in the cylinder head, contaminating the ignition coil boot. You will have to repair the oil leak and replace the ignition coil boot (or ignition coil). Inspect the valve cover once the gasket has been removed. It can crack from heat or impacts. I sometimes find cracks around the grommet sealing holes or at the front near the VANOS actuator. If you find a crack, you will have to replace the valve cover.

To avoid marring the paint and trim, work with a plastic prying tool or wrap a screwdriver tip with masking tape before prying out body or interior items.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability. 

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Remove the engine cover on the cylinder head. See our tech article on engine cover removing.

Models with 4-cylinder engine:
Models with 4-cylinder engine - In order to access the rear of the valve cover, I like to detach wiring harness housing; this allows a little more movement at the back of the valve cover.
Figure 1

Models with 4-cylinder engine - In order to access the rear of the valve cover, I like to detach wiring harness housing; this allows a little more movement at the back of the valve cover. Remove the two Phillips head screws (green arrows).

Models with 4-cylinder engine - Next, remove the E-box seal from the right side engine compartment (green arrow).
Figure 2

Models with 4-cylinder engine - Next, remove the E-box seal from the right side engine compartment (green arrow).

Models with 4-cylinder engine - Then unclip the plastic harness retainer.
Figure 3

Models with 4-cylinder engine - Then unclip the plastic harness retainer. There are a total of eight clips (green arrows). Four are shown here, the other four are on the opposite side of the panel. Once unclipped, remove the retainer from the E-box by lifting it up.

Models with 4-cylinder engine - Now you can remove the wiring harnesses from the mounting points.
Figure 4

Models with 4-cylinder engine - Now you can remove the wiring harnesses from the mounting points. This will allow the plastic housing above the valve cover to be moved out of your way.

Models with 4-cylinder engine - Next, remove the two 10mm nuts (green arrows) for the wiring harness housing mount.
Figure 5

Models with 4-cylinder engine - Next, remove the two 10mm nuts (green arrows) for the wiring harness housing mount. Then remove the mount from the firewall. Repeat this for the right side mount.

Models with 4-cylinder engine - Working at the right side bulkhead, cut the wire tie securing the harness to the firewall.
Figure 6

Models with 4-cylinder engine - Working at the right side bulkhead, cut the wire tie securing the harness to the firewall.

Models with 4-cylinder engine - Then remove the crankcase breather hose (green arrow) from the rear corner of the valve cover.
Figure 7

Models with 4-cylinder engine - Then remove the crankcase breather hose (green arrow) from the rear corner of the valve cover. Pull it straight off. If it is brittle or torn, replace it.

Models with 4-cylinder engine - Working at the ignition coil, rotate the electrical connect counterclockwise to disconnect (green arrow).
Figure 8

Models with 4-cylinder engine - Working at the ignition coil, rotate the electrical connect counterclockwise to disconnect (green arrow).

Models with 4-cylinder engine - Next you can remove the two 8mm nuts (green arrows) from the ignition coil mounting bracket studs.
Figure 9

Models with 4-cylinder engine - Next you can remove the two 8mm nuts (green arrows) from the ignition coil mounting bracket studs.

Models with 4-cylinder engine - Lift the ignition coil up and off the mounting bracket and lay aside.
Figure 10

Models with 4-cylinder engine - Lift the ignition coil up and off the mounting bracket and lay aside.

Models with 4-cylinder engine - Next you have to loosen the two 10mm ignition wire loom fasteners (green arrows).
Figure 11

Models with 4-cylinder engine - Next you have to loosen the two 10mm ignition wire loom fasteners (green arrows). Loosen the nuts about three turns.

Models with 4-cylinder engine - Then slide the ignition loom with mounting bracket (green arrow) up and out of valve cover.
Figure 12

Models with 4-cylinder engine - Then slide the ignition loom with mounting bracket (green arrow) up and out of valve cover.

Models with 4-cylinder engine - Once the loom is free, remove each spark plug wire from the spark plugs.
Figure 13

Models with 4-cylinder engine - Once the loom is free, remove each spark plug wire from the spark plugs. Then remove the ignition wires and ignition coil as a unit. Store them is a safe place, avoid getting fluids on them during the repair.

Models with 4-cylinder engine - Using a flathead screwdriver, lever out the plastic bracket from the valve cover.
Figure 14

Models with 4-cylinder engine - Using a flathead screwdriver, lever out the plastic bracket from the valve cover. There are four plastic retaining tabs (green arrows) you have to disengage. Lever next to tab to remove.

Models with 4-cylinder engine - Remove fifteen 10mm valve cover fasteners (green arrows).
Figure 15

Models with 4-cylinder engine - Remove fifteen 10mm valve cover fasteners (green arrows). The fasteners at the center near the spark plug holes will come out, the others around the perimeter will stay in valve cover. Be sure they are all loose before attempting to remove valve cover.

Models with 4-cylinder engine - Lift valve cover off cylinder head.
Figure 16

Models with 4-cylinder engine - Lift valve cover off cylinder head. If valve cover is stuck to cylinder head, check that you didn'Â't miss a fastener. Once you are sure all the fasteners have been loosened completely, it may require a gentle tap with a rubber mallet to free it up.

Models with 4-cylinder engine - Once the valve cover has been removed, pull valve cover gasket out of valve cover.
Figure 17

Models with 4-cylinder engine - Once the valve cover has been removed, pull valve cover gasket out of valve cover. Then thoroughly clean valve cover sealing groove. Be sure to remove and clean the ignition plug hole seals also.

Models with 4-cylinder engine - Remove sealing grommets from valve cover fasteners and replace with new.
Figure 18

Models with 4-cylinder engine - Remove sealing grommets from valve cover fasteners and replace with new. Install new valve cover gasket into sealing groove in valve cover.

Models with 4-cylinder engine - Use a plastic scraper and clean the cylinder head sealing surface.
Figure 19

Models with 4-cylinder engine - Use a plastic scraper and clean the cylinder head sealing surface.

Models with 4-cylinder engine - Once clean, apply a small amount of RTV sealant to the timing cover to cylinder head joining area (green arrow).
Figure 20

Models with 4-cylinder engine - Once clean, apply a small amount of RTV sealant to the timing cover to cylinder head joining area (green arrow). Make sure to do this on both sides of the cylinder head. Left side shown in photo. Install new valve cover and seals to valve cover. Be sure it is properly inserted into groove and fits well. Place valve cover on cylinder head and install all fasteners finger tight. Then tighten fasteners in a cross-cross pattern. Reinstall ignition coil and wires. Reconnect crankcase breather hose. Reinstall wiring harnesses and mounting bracket as previously installed. Start and idle engine, inspect valve cover and surrounding areas for oil leaks. Once complete, reinstall engine cover.

Models with 6-cylinder engine:
Models with 6-cylinder engine - This section of the tech article will use photos from an M54 engine from a similar model.
Figure 21

Models with 6-cylinder engine - This section of the tech article will use photos from an M54 engine from a similar model. If you have trouble with clearance, remove the wiring harness loom and mount as described in 4-cylinder valve cover earlier. Remove engine covers. See our tech article on engine cover removing. Using a small flathead screwdriver, release the ignition coil electrical connector retainer by prying up, then pull the electrical connector out of the ignition coil (green arrow). Do this for all six ignition coils.

Models with 6-cylinder engine - Next remove two 10mm ignition coil fasteners (green arrows).
Figure 22

Models with 6-cylinder engine - Next remove two 10mm ignition coil fasteners (green arrows). Do this for all six ignition coils.

Models with 6-cylinder engine - Remove the ignition coil from cylinder head by pulling straight up.
Figure 23

Models with 6-cylinder engine - Remove the ignition coil from cylinder head by pulling straight up. If coil resists, twist when pulling up to break free from spark plug. The ignition coil rubber boot can become stuck to the spark plug over time. Do this for all six ignition coils.

Models with 6-cylinder engine - Working at the center of the valve cover, remove the 8mm nut and ground strap from valve cover fastener (green arrow).
Figure 24

Models with 6-cylinder engine - Working at the center of the valve cover, remove the 8mm nut and ground strap from valve cover fastener (green arrow).

Models with 6-cylinder engine - Unclip the ignition coil wiring harness from the valve cover by pulling up and remove it from engine (green arrow).
Figure 25

Models with 6-cylinder engine - Unclip the ignition coil wiring harness from the valve cover by pulling up and remove it from engine (green arrow).Once unclipped, lay on left side of engine out of your way.

Models with 6-cylinder engine - Next, pull the oxygen sensor electrical connectors out of holder and lay aside (green arrows).
Figure 26

Models with 6-cylinder engine - Next, pull the oxygen sensor electrical connectors out of holder and lay aside (green arrows). Then remove secondary air vacuum hose from holder and lay aside (your vehicle may have the oxygen sensor connectors in a different location, you may be able to skip this step).

Models with 6-cylinder engine - Remove the fifteen 10mm valve cover fasteners (green arrows).
Figure 27

Models with 6-cylinder engine - Remove the fifteen 10mm valve cover fasteners (green arrows).

Models with 6-cylinder engine - Lift the valve cover off cylinder head.
Figure 28

Models with 6-cylinder engine - Lift the valve cover off cylinder head. It should not be stuck to cylinder head, if it is stuck, check that you didn'Â't miss a fastener.

Models with 6-cylinder engine - Once the valve cover has been removed pull valve cover gasket out of valve cover.
Figure 29

Models with 6-cylinder engine - Once the valve cover has been removed pull valve cover gasket out of valve cover. Then thoroughly clean valve cover sealing groove. Remove sealing grommets from valve cover fasteners and replace with new. Install new valve cover gasket into sealing groove in valve cover.

Models with 6-cylinder engine - Then apply a small amount of RTV to seams at VANOS actuator (green arrows) and cylinder head.
Figure 30

Models with 6-cylinder engine - Then apply a small amount of RTV to seams at VANOS actuator (green arrows) and cylinder head. Place valve cover on cylinder head and install all fasteners finger tight. Then tighten fasteners in a cross-cross pattern. Reinstall ignition coils and install and route wiring harness as previously installed. Start and idle engine, inspect valve cover and surrounding areas for oil leaks. Once complete, reinstall engine covers.

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Comments and Suggestions:
Ray Comments: thank you Nick for your prompt response. I only have the valve cover out when ee toI saw the gap from the timing belt cover. I have not been able to work on it but as soon as I can got to take it apart to see way.Is it simple to take the belt cover off.
September 22, 2016
  Followup from the Pelican Staff: OK, let me know what you find. - Nick at Pelican Parts  
Ray Comments: my timing belt cover sits 1/8 higher then my motor block so when putting the valve cover it does not sit flat what would you recomend
September 21, 2016
  Followup from the Pelican Staff: Check if it is not the teeth correctly. Or the part is not right. - Nick at Pelican Parts  
diva_3181377 Comments: Thanks Nick. This is a video recorded on 2014 2 years ago..roughly 7K mile before https://www.youtube.com/watch?v=FcB_gWFujr4 .

Seems the new video, the sound is slightly decreased? Did 2 oil changes after this one with engine cleaner.

If it is low oil pressure, how to find it? On the chain tensioner ? If i put the hand on the left top of the engine when facing the engine, exhaust side, i can feel is in my hand. Vanos was rebuilt 2-3 years back.
September 13, 2016
  Followup from the Pelican Staff: Use an oil pressure gauge to measure oil pressure.

The noise will resonate, you could be feeling that. - Nick at Pelican Parts
 
diva_3181377 Comments: Please listen to https://www.youtube.com/watch?v=6LOAiXdUlxE

Does it sound like upper tensioner? Or some bearing?

I removed both belts and tried. Sound is still there. I am using Mobil 0W40. Car is 2000 Z3 2.3 with 128K on it. M52TU engine 2.5L CVV system seems to be good. It sounds like something rubbing?

Thanks
September 9, 2016
  Followup from the Pelican Staff: I can't be sure from a video. In person I can move around the engine see where the sound comes from. Sounds like a bearing or lack of oil pressure. - Nick at Pelican Parts  
Kman Comments: I also found some oil pooling up in 2 of my spark plug holes, how would you recommend getting the oil out? I don't want to damage the plugs or have any un-wanted material like paper towel getting caught in there.
Thanks
July 18, 2016
  Followup from the Pelican Staff: I usually place rags (paper lint free) down into the hole to absorb. Repeat until clean. use a pick to push down around and pull out when oil is absorbed. - Nick at Pelican Parts  
Kman Comments: I just did this DIY and replaced the gasket and added a good amount of RTV on my 4 cylinder z3 and I over torqued the last valve cover bolt. This resulted in the threads inside the hole to break/disappear.
I decided to buy a thread repair kit, and my question is
Do I need to take off the cover again to re-thread this hole? or can I leave the cover on to do it? Which I would prefer doing because the RTV and new gasket
July 18, 2016
  Followup from the Pelican Staff: Yes, remove the valve cover to repair the threads. - Nick at Pelican Parts  

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Page last updated: Mon 12/5/2016 02:07:22 AM