- 8 Min Read
- By: Tony Robinett
BMW E36 M3 Single VANOS Unit Replacement
If you’re driving around in an E36 BMW M3, chances are likely that you will be a victim to the dreaded but ever-so-common Vanos failure, or noise from the Vanos unit itself. Symptoms of a worn out Vanos unit can include hesitation/loss of power below 3k RPM, higher fuel consumption, and/or a CEL with a cam position sensor code or a P1519 code which reads "Vanos Stuck." Removal of the Vanos Unit requires only a few hours of time, a few replacement parts and a few specific tools.
- 24mm Wrench & 19mm Wrench
- 22mm, 19mm, 13mm, 10mm, 10mm deep socket, 8mm, and an E-10 Torx Socket
- 1/2”, 3/8”, 1/4” Ratchets – Also Long Arm 3/8” and 1/2" ratchets
- Torque Wrench
- BMW Timing Tools
- Fan Removal Tools - 32mm wrench, water pump pulley holder, and a handheld sledge hammer
- Fan shroud removal tools - 4” long piece of 5/16” tubing and two small clamps
- Tools while you work - Paper towels, water based cleaner, PB Blaster, Brake Cleaner, synthetic engine oil (same weight and brand as you are currently using), RTV gasket sealant
The BMW Timing tools are an essential if you are going to do this yourself. Baum Tools makes a kit you can purchase from an Ebay store, El Paso Tool Store for under $100.00. Or you can rent the tools from a few different places, the most popular being Dr. Vanos for only $35. I opted for buying my own set for ease of mind knowing I had the tools if I ever had to do this again. The water pump pulley holder is also found at the El Paso Tool store.
Along with tools you will need replacement parts:
- Vanos Gasket
- Vanos Oil hose washers (2)
- Optional Parts: If you have over 45k miles on these parts I recommend you replace them - Valve Cover Gasket, Valve Cover Bolt Grommets, and Spark Plug gaskets.
To kick off the job you want to remove the fan and shroud first, it may seem like a pain, but it’s necessary to get the extra hand room you need.
Fan and Shroud Removal
- Start by removing the air duct/radiator cover, there should only be 4 screws and a few rivets securing it down. Next you need to disconnect the air duct that goes to the alternator. If you lift gently the air duct/radiator cover should lift from the vehicle.
- With a Philips screw driver unscrew the overflow hose clamp at the top right of the radiator. Pry the hose off of the overflow neck and be sure not to lose the hose clamp.
- Remove the top two rivets at the top corners of the fan shroud. Pry out the middle pin, then the whole rivet base.
- Place the 5/16” hose on the overflow neck and clamp the opposite end of the hose to prevent coolant leak.
- Now for removal of fan: placing the 32mm wrench on the fan clutch nut, and mounting the pulley holder on the water pump pulley bolts; counter hold the tools and break the nut seize. Remember it is a left handed thread – left=tight, right=loose.
- Spin the fan until it unthreads all the way, be sure the fan doesn’t fall and damage itself or the radiator.
- Next, remove the coolant level sensor at the bottom of the coolant reservoir.
- Remove the coolant hose from the bottom brackets of the fan shroud.
- Lift up on the fan shroud and start to remove, the hose going to the reservoir should still be attached, the hose will bend as you lift.
- When fully removed rotate the shroud and lay it on the right side of the engine bay.
- Installation is the opposite of removal- when installing the cooling fan spin the fan onto the threads and place the 32mm wrench on the clutch nut. Lightly strike the top of the wrench once to tighten the fan, and remember it’s a left hand thread. The belt frictional forces are strong enough to tighten the clutch nut, and the fan spins in the tightening direction of the nut.
Removing the Vanos - Starting at the Top
Removing the Valve Cover
- Pry off the caps covering the top cover mounting hardware-two on the left cover, and two on the right cover.
- Pull the right cover off, remove the oil filler cap and remove the right cover, then reinstall the oil filler cap.
At this point you should see your coils.
- Remove the valve cover vent hose at the front right of the valve cover, pull over to the side.
- Start disconnecting the ignition coil electrical harness’s- Lift the metal locking tab and pull.
- Remove the coil harness ground wire between coils 2-3.
- Now start removing the coils, two bolts per coil. There are coil ground straps at coils 1 &6. Keep an order of coil-cylinder relation.
- Next, start removing the perimeter valve cover bolts with the washers and grommets. There should be 11.
- Remove the 4 mounting bolts in the center of the valve cover- the third bolt in from the front looks like the perimeter bolts.
- At this point the valve cover should be free to remove, if there is resistance use a small putty knife to beak the bond. If it refuses to come off, recheck to make sure all 11 perimeter & 4 middle mounting bolts have been removed.
- Remove the gasket & gently scrape any gasket material from head surface.
- Remove the spark plug well gaskets.
At this point you should see the exhaust camshaft on the left and a black cover on the right over the intake camshaft.
- Lift up on the intake camshaft cover and place it aside.
Locking the Timing
- Turn the crankshaft pulley clockwise until cylinder 1 intake and exhaust cam lobes are pointed at each other at a 45°.
- The square at the end of the exhaust camshaft should be flush with cylinder head surface.
- Inspect the TDC markings on the timing cover and the harmonic balancer; adjust the crankshaft pulley to align the markings.
- Leaving the timing where it’s at, raise the vehicle and put it on jack stands.
- Locate the crankshaft lock hole plug at engine right rear; pry out the plug with a narrow screw driver.
- Insert the crank shaft lock pin into the crankshaft lock hole. When the pin is fully engaged the crankshaft pulley will be locked in place, but still have minor movement.
If the pin doesn’t go in or doesn’t lock fully, do not force it. I had difficulty getting it to engage fully; so I just made sure my TDC markings were aligned as best as I could, and that the squares on the ends of the camshaft were flush with the cylinder head surface. And I made sure not to bump or turn the crankshaft pulley.
- You can lower the car at this point if you wish. Remove the 3 valve cover mounting studs at the rear of the engine head.
- Next, take the exhaust camshaft lock block and place it on the rear square. It may not sit flush on the engine head; so take the 24mm wrench and adjust the camshaft to allow the block to sit flush against the engine surface.
- Next, install the intake camshaft lock block and perform the same steps as above to get it to sit flush on the engine surface.
Removing the Vanos Unit
- Start by removing the Vanos oil hose and banjo bolt. There are two washers one on each side of the contact surfaces. Throw the washers away.
- Remove the engine lift bracket at the Vanos solenoid. Two 13mm bolts.
- Disconnect the Vanos solenoid connector
- Remove the vacuum pipe connected by two 10mm nuts underneath the Vanos Unit.
The pipe should lay down on the thermostat housing and hoses.
- Remove the two 19mm access bolts in front of the exhaust sprocket on the Vanos Unit.
- Remove the four Torx bolts mounted to the exhaust sprocket.
Be careful not to drop any bolts, work slowly, and place a rag or towel underneath the sprocket to catch any potential bolts. Then remove.
- Pressing down on the chain tensioner insert the camshaft chain tensioner pin.
Install the pin underneath the chain.
- Locate and remove the 6 mounting nuts on the front lower half of the Vanos Unit.
The first nut from the right and the second from the left were removed when the vacuum pipe was removed.
- Now, cover the lower belts with a towel to protect them from oil drops. If possible place a small bag (Ziploc) over the Vanos oil feed hole to catch leaking oil.
- The final step! (And possibly the most intimidating.) Mount the sprocket turning tool onto the exhaust sprocket.
Wiggle the Vanos Unit forward, off the engine, while turning the exhaust sprocket clockwise.
The turning of the sprocket allows the chain to relax, which allows the intake sprocket to rotate and release the Splined Vanos shaft.
- Remove the Vanos Unit fully and drain the rest of the oil out of the oil feed hole.
- Do not set the Vanos Unit down on its splined shaft, always set it with the inner side facing up.
- Remove and throw away the Vanos gasket at the engine.
Installation of Vanos
For the most part installation is exactly the opposite of the removal, but certain care should be taken at certain steps for a proper installation of the Vanos Unit.
- First things first, make sure the old Vanos gasket is removed and the mating surfaces are clean.
- Install the new Vanos gasket.
- Install the sprocket turning tool on the exhaust sprocket and rotate it clockwise as far as it will go. This turns the intake sprocket clockwise as well, and is important for installation.
- Now, fully insert the splined shaft on the Vanos Unit into the splined intake sprocket hole.
The splined shaft will rotate slightly as it enters the sprocket, and will stop.
- Next, with the sprocket turning tool on the exhaust sprocket, turn the exhaust sprocket counter-clockwise while pushing on the Vanos unit. You may have to wiggle the Vanos or the socket tool to get it to insert properly.
- The Vanos Unit should be mated against the engine head.
- Now, install the 6 Vanos mounting nuts, tighten evenly, working back and forth. Fully tightened is 6 ft-lb.
- Remove the camshaft chain tensioner pin, push down on chain tensioner and pull the pin out.
- Next, install the mounting bolts on the exhaust sprocket, tighten in a crisscross pattern. Fully tightened is 15 ft-lb.
- Install the two exhaust sprocket access bolts. Fully tightened is 37 ft-lb.
- Install the Vacuum pipe onto its mounting studs. Tighten to 6 ft-lb.
- Re-connect the Vanos solenoid electrical connector. Press in till it snaps in place.
- Re-install the engine lift bracket-Long Bolt on top, small on the lower. Fully tightened is 6 ft-lb.
- Install the Vanos Oil Line with two new washers- Put a washer on the bolt, put the bolt through the hose end, then add the other washer. Fully tightened is 24 ft-lb.
Unlocking the Timing
- Remove the camshaft locking blocks
- Remove any gasket sealant or compound on the engine head, half-moon corners with a gasket scraper.
- Install the 3 valve cover studs in the rear of the engine head. Fully tightened is 6 ft-lb
- Now, raise the front of the car, (if you ever took it off the jack stands) put it on jack stands and remove the crankshaft locking in from the crankshaft lock hole. Insert the plug into the hole.
- You can now lower the car for the rest of the installation.
Installing the Valve Cover
- Install the intake camshaft cover, the open end should face the front. Gently press down on cover to lock the cover on the valve train tabs. Should have no vertical movement when fully installed.
- Install the valve cover perimeter gasket and the spark plug gaskets on the valve cover.
- Before you install the valve cover you need to add some RTV gasket sealant to a few areas:
- The contact spots where the Vanos meets the engine head.
- The half-moon corners at the back of the engine head.
- Allow the sealant to sit for a few minutes before installing the valve cover.
- Install the valve cover onto the engine head/Vanos; be sure that it is aligned properly.
- Install the 11 bolts with the washer and grommets at the cover perimeter.
- Install the 4 valve cover bolts in the center of the valve cover- remember the 3rd bolt from the front is the same as the perimeter bolts.
- Tighten the bolts back and forth adding even pressure around the perimeter. Fully tightened is 7 ft-lb.
- Install the coils to their corresponding cylinder; rotate between coil mount bolts to tighten evenly. Fully tightened should be 7 ft-lb.
- Install the electrical harness to each of the coils.
- Install the coil harness ground wire on the valve cover bolt between cylinder 2 & 3.
- Re-Install the valve cover vent hose at front right of valve cover.
- At this point install the engine covers and you’re DONE!
Before starting your car make sure all tools are away from the engine compartment. Make sure your car is back to the same way it was before you started. Look for my article on rebuilding a single VANOS unit in the upcoming weeks!
About the Author: Tony Robinett
Tony lives in Spokane, Washington and is a 3-D Design Engineer, machinist, and welder. When he's not at work he is designing and fabricating parts for his M3, and other BMWs alike.
Tony lives in Spokane, Washington and is a 3-D Design Engineer, machinist, and welder. When he’s not at work he is designing and fabricating parts for his M3, and other BMWs alike.