This article gives detailed instructions on replacing the PCV valve in a BMW M60 8 cylinder engine. Even though we used a 1995 840i to perform this repair, this article can be applied to any vehicle with the M60/M62 V8 engine including 5, 7, 8 and X5 series vehicles with minor modifications to the repair steps.
The BMW M60 PCV valve is a common source of vacuum leaks and a rough idling engine.
The PCV valve (or positive crankcase ventilation valve) is located on the rear of the intake manifold on the BMW M60 V8 engine. It is a simple one way check valve that allows the gases that build up in the crankcase to be channeled back into the intake manifold for combustion. It is considered part of the emissions system since it recycles gases that did not ignite during combustion (“blow by gas”) instead of allowing them to be vented into the atmosphere.
Like all the other parts in the engine compartment of your vehicle, the BMW M60 PCV valve has a definitive service life and will eventually need to be replaced. There are many signs of a failing PCV valve; the most prominent examples include a rough or erratic idling motor, engine surging while idling or driving, and a leaking PCV valve gasket. The PCV valve, its gasket and all of its rubber vacuum caps should be always be replaced together.
What is the correct way to replace the BWW M60 PCV valve?
The proper method of replacing the BMW M60 PCV valve remains a common source of contention among BMW mechanics. Because of its close proximity to the firewall, it is very difficult to navigate around the rear of the intake manifold…especially with a socket wrench and torx bit. Compounding the difficulty is the fact that the heads on the mounting bolts securing the PCV valve to the intake manifold are notorious for stripping. Some mechanics have been known to use a Dremel tool to cut the heads off of the PCV valve mounting bolts to avoid removing the intake manifold. This is not an acceptable way to remove the PCV valve on an M60/M62 engine and should never be attempted.
As you can see from the following photo, space is very limited behind the PCV valve on this 1995 840i with an M60 8 cylinder engine. These mounting bolts are virtually impossible to remove with a socket wrench and torx bit.
The correct method for removing the PCV valve on the M60/M62 engine is to first remove the intake manifold from the vehicle. Removing the intake manifold allows clear unobstructed access to the PCV valve so it can be serviced properly without damaging any other components in the engine compartment. Its also an excellent time to replace the intake manifold gaskets that could have been damaged by the faulty PCV valve, as well as a rare opportunity to service other important parts like the valley pan gasket, the fuel injectors and cleaning the engine. Removing the intake manifold should not be considered a deterrent to performing a BMW M60 PCV valve replacement, but rather a chance to get caught up on all of the other well needed service that your V8 needs.
1. PCV valve and gasket (required) – The BMW M60 PCV valve can be purchased from a number of different aftermarket manufacturers…we give you several choices below based on your brand preference and budget. The PCV valve gasket is not included with the valve and must be purchased separately.
2. Vacuum caps (required) – We can’t stress enough the need to replace the two vacuum caps on the back of the PCV valve when doing this repair. These vacuum caps are notorious for drying out and cracking, and are a major cause of rough idling engines.
3. PCV valve mounting bolts (optional) – The T30 PCV valve mounting bolts are notorious for stripping on the M60/M62 8 cylinder engine. Their soft metal combined with age causes the torx bit to strip the head during removal. The following is a link for ordering new factory replacement bolts.
4. Fuel pressure sensor vacuum line (optional) – The fuel pressure sensor vacuum line connects the injector pipe to the PCV valve. It is very common for this vacuum line to crack as it ages, causes air leaks and a rough idling engine. Now is the time to replace this inexpensive part while you have the intake manifold off of the vehicle.
5. Intake manifold gaskets (optional) – Although we list this part as optional, we strongly recommend replacing them when doing this repair. Intake manifold gaskets are inexpensive, so it doesn’t make sense not to purchase high quality OEM replacements.
6. Intake manifold spacer bushings (optional) – Just as important as the gaskets are the intake manifold spacer bushings. The spacer bushings ensure the proper amount of pressure is put on the intake manifold gaskets so they create a tight seal.
Removing the intake manifold from an M60/M62 engine is a very straightforward procedure and should not be intimidating in any way. It is important to remember that you are working on an engine that is close to 30 years old. Use patience and care during disassembly…especially with plastic parts like the wiring harness (“loom”). Forcing the wiring harness connections apart can cause them to crack and break, turning your intake manifold replacement into a $1000 plus repair. For more a more detailed discussion on the M60 intake manifold, please see our article BMW M60 Intake Manifold Gasket Replacement – V8 5,7,8 Series.
- Use a socket wrench to disconnect the negative terminal from the battery before starting this repair. Always cover the terminal with a clean rag to avoid accidental contact during the repair. If working on a vehicle with 2 batteries (8 series), disconnect the negative terminal from both batteries. ALWAYS disconnect the battery(s) before performing any type of mechanical repair, especially in the engine compartment.
- Remove the four 10mm nuts anchoring the top engine cover. Remove cover from engine compartment.
- Disconnect the idle control valve by pinching in the metal release clip and pulling the plug free.
- Next, disconnect the throttle body.
- Use a flatblade screwdriver to raise the metal locking clip on the throttle valve switch. Pull the plug free and gently stow out of the way.
- Disconnect the mass air flow sensor’s (MAF) electrical connection.
- Use a flatblade screwdriver to release the seven metal clips that secure the lid on the intake muffler.
- Loosen the hose clamp connecting the intake muffler to the intake boot. Remove the intake muffler from the vehicle.
- Grasp the idle control valve and pull it free from the intake manifold. Disconnect the idle control valve hose from intake boot and remove from the vehicle.
- Loosen the hose clamp that secures the intake boot to the secondary throttle housing (ASC+T unit). Remove the intake boot from the vehicle.
- Next, remove the Bowden cable from the bottom of the secondary throttle housing by pushing the spring mechanism back to release the tension on the cable. With the tension released, grab the cable’s barrel fitting and pull it off of the spring mechanism as shown below. Using an inspection mirror helps in locating the barrel fitting. Stow the cable safely out of the way.
- Disconnect the accelerator and cruise control Bowden cables from the throttle body by grasping their black plastic cable stops and pulling them free of the spring mechanism.
- Use a T30 torx bit to remove the two throttle body mounting bolts anchoring the cable bracket. These bolts are notoriously prone to stripping. If you strip the heads, use a 1/4″ drill bit to snap the heads off as shown below. You can order new bolts by clicking here.
- Disconnect the plastic retaining clip anchoring the cable to the cover bracket. Lay the throttle cable bracket safely to the side away from the work area.
- Loosen the hose clamp on the vacuum line connecting the fuel vent valve to the throttle body. Pull the vacuum line free of the valve.
- Moving to the rear of the engine, remove the hood gasket from the heater closing panel and lay it safely outside the work area.
- Remove the three trim locks from the top of the microfilter (cabin filter) cover.
- Using a 10mm socket wrench, remove the plastic retaining nut at the top of the cover. Remove the microfilter cover from the vehicle.
- Using a 7mm socket wrench, remove the two screws anchoring the heater closing panel to the body of the vehicle. Remove the panel from the vehicle.
- Remove the sound insulation from the back of the intake manifold.
- Next, the main engine wiring harness (also known as “the loom”) must be disconnected so it can be moved out of the work area. As previously discussed, it is critical that care is taken during these next steps to avoid breaking the harness.
- Start by unplugging the connections on the left side of the engine as shown below. DO NOT force the plugs out. We strongly recommend marking and labeling each connection with high visibility tape to avoid confusion during reassembly.
- Next, remove the right side connections.
- Moving to the rear of the engine, remove the wiring harness’ two main connectors by turning their locking rings counterclockwise until they release. DO NOT attempt to pry them off – simply turning the locking ring counterclockwise as far as it will go will release the plug from the harness without using any force.
- Carefully store the main wiring harness connections safely out of the work area.
- Use a 10mm socket wrench to remove the bolts anchoring the side engine covers. Remove the covers from the vehicle.
- Unclip the eight ignition coils by releasing their metal clips and pulling the plugs free.
- Disconnect the intake air temperature sensor on the front right of the intake manifold.
- Use a 10mm socket wrench to remove the four nuts anchoring the wiring harness to the main fuel line.
- Next, locate the metal locking clips that anchor the wiring harness to fuel injectors.
- Starting on the left side, begin to unlock the clips. Note that you only have to pull one side of the clip loose. We suggest using a metal pick as shown below.
- Continue to unlock the rest of the fuel injector clips on the left side. The interior clips can be tricky. Take your time and use a bit of ingenuity to get to them. You may have to actually lay inside the engine compartment to get the rear ones.
- Once all of the clips have been released, grasp the left wiring harness and pull it free from the fuel injectors. DO NOT force it off. If the wiring harness will not come free you have not properly released a clip…you will need to go back and check them.
- With the wiring harness free, return the clips to their fully locked position…this will keep you from losing any of them and have them ready for reassembly.
- Repeat the above steps on the right wiring harness.
- GENTLY and CAREFULLY fold the left wiring harness over to the right side of the engine so it is clear of the intake manifold work area. You may have to “reroute” the alternator sensor wire so you have enough slack to fold over the harness.
- The fuel injection pipe does not have to be removed to perform a BMW M60 intake manifold replacement, but the fuel feed and return lines do need to be disconnected. Start by identifying the fuel injection pipe and the fuel feed line on the right rear of the intake manifold.
- Loosen the hose clamp on the fuel feed line and pull it free. Often these lines are very tight…use a flat blade screwdriver to assist removal if necessary.
- Move to the other side of the manifold. The fuel return line is attached to the right rear of the fuel injection pipe. If you are able to remove it now that’s fine…if you cannot get a firm grip on it without breaking the fuel line then wait until step 5 below.
- Using an 11mm socket wrench, remove the ten intake manifold mounting nuts.
- Grasp the manifold and pull it loose from the cylinder head. If you were not able to remove the return fuel line in step 3 above then remove it now.
- Tilt the intake manifold on its side and locate the vent pipe where it attaches to the PCV valve. Grasp the fixing clamp and pull it free from the vent pipe connection. Pull the vent pipe free from the PCV valve.
- The intake manifold can now be removed from the vehicle.
Now that the intake manifold has been removed from the vehicle, replacing the PCV valve and its gasket is a simple procedure that can be done the correct way. Removing the intake manifold on your M60/M62 engine is a rare event, so take advantage of the opportunity to do some housecleaning and service! Now is also an excellent time to clean the intake manifold and remove any carbon deposits. It is also an exceptional time to clean the engine block, valve covers and cylinder head. Removing the intake manifold gives you clear access to the valley pan gasket and the water temperature sensors in the cooling system that probably need to be replaced. Save yourself time and money and do every service item you can while the manifold is removed from the vehicle.
- Place the intake manifold on a bench. Identify the PCV valve mounted to the rear of the manifold.
- Remove the vacuum line that connects the PCV valve to the fuel pressure regulator. If this vacuum line is old like ours, we suggest replacing it. You can order a new one by clicking here.
- Using a high quality T30 torx bit (one that does not have the edges rounded off on it) attempt to remove the seven PCV valve mounting bolts. Flip the manifold over to get better access to the lower mounting bolts. Even with the intake manifold removed they are difficult to extract. If you strip one, let it go and move to the next bolt.
- As you can see…we only ended up stripping the heads on two bolts. When dealing with older bolts on an M60/M61 intake manifold…that should be considered an acceptable outcome. If you stripped bolts removing your PCV valve, you can reorder new ones in our parts list or by clicking here.
- If you strip any of the mounting bolts, use a 1/4″ drill to snap the heads off. If you stripped bolts removing your PCV valve, you can reorder new ones in our parts list or by clicking here.
- With all of the mounting bolts extracted, remove the PCV valve from the intake manifold.
- Remove the PCV valve gasket from the intake manifold.
- Thoroughly clean out the groove that the PCV valve gasket mounts in. Now is also an excellent time to clean out the carbon deposits and oil residue from inside the intake manifold. Spray CRC Clean-R-Carb liberally inside the intake manifold and wipe it out with a soft cloth.
- When you are finished cleaning the intake manifold, install a new PCV valve gasket. Make sure it is pressed in firmly.
- Install a new PCV valve and torque the bolts to 10 Nm (7.5 ft-lb).
- Install new vacuum caps on the PCV valve. It is strongly recommended that you do not use old vacuum caps. If you did not purchase new ones, please see our parts section to quickly order them.
Reassembling the vehicle is very straightforward with no special procedures. We highly recommend replacing the intake manifold gaskets and spacer bushings during reassembly…it will ensure your manifold has a nice tight seal without any vacuum leaks (see our parts list if you have not purchased any).
Take your time during reassembly making sure not to miss any vacuum or electrical connections. We have provided a comprehensive checklist with the exact steps for reassembly. It also includes all of the critical torque values for your convenience.
BMW M60 PCV Valve Reassembly Checklist
- Reinstall the vacuum line that attached the PCV valve to the fuel pressure regulator.
- If you removed the spacer bushings, or are replacing them with new ones, install them back into the intake manifold now.
- Place the intake manifold back in the engine on its left side and connect the vent pipe to the PCV valve. Install the fixing clamp back on the vent pipe connection.
- Position the intake manifold on its mounting studs and install the ten mounting nuts. Torque the nuts to 15 Nm (11 ft-lb).
- Reinstall the fuel return line at the right rear of the manifold and tighten the hose clamp.
- Reinstall the fuel supply line at the left rear of the intake manifold and tighten the hose clamp.
- Fold the left wiring harness back over into position. If you had to temporarily reroute any wires like the alternator sensor, put them back into their proper position now.
- Snap the left and right wiring harnesses back onto the fuel injectors. Make sure all of the metal clips snap into place.
- Reinstall the four wiring harness mounting nuts an torque them to 10.5 Nm (8 ft-lb).
- Plug the intake air temperature sensor back in.
- Plug the ignition coils back in and replace the side engine covers.
- Plug the two round wiring harness connections back in at the rear of the manifold. Turn the locking rings clockwise until they are snug.
- Plug the six wiring harness connections back paying careful attention not to mix them up.
- Replace the sound insulation at the back of the manifold.
- Reinstall the heater closing panel and the microfilter cover.
- Reinstall the rubber engine gasket.
- Reconnect the fuel vent valve vacuum line and tighten its hose clamp.
- Reinstall the throttle cable bracket onto the throttle body. Torque the two mounting bolts to 10 Nm (7 ft-lb).
- Reinstall the accelerator and cruise control cables back onto the throttle body.
- Reconnect the Bowden cable to the secondary throttle housing.
- Reconnect the intake boot to the secondary throttle housing.
- Reinstall the throttle control valve and reconnect it to the intake boot.
- Reinstall the intake muffler lid to the intake boot. Clip the lid back onto the base of the intake muffler.
- Reconnect the mass air flow (MAF) sensor.
- Plug in the throttle valve switch.
- Plug in the throttle body.
- Plug in the idle control valve.
- Replace the engine cover.