Most of the BMW E36s still on the road today have well over 100,000 miles. If that is the case with your E36, it’s likely that your CCV has been replaced or needs to be replaced soon. By now, your BMW E36 likely burns off a little bit of oil every 1,000 miles or so. Not enough to be an issue. If you recently noticed that your E36 is burning off more oil than it used to, than you may have a CCV that needs to be replaced.
The BMW E36 CCV is an extremely important component of your vehicle’s engine. It reduced crankcase pressure and removes oil vapor from the exhaust. Failure of the CCV can result in increased oil consumption, rough idling, and even catastrophic engine failure.
Luckily, in this article, you will learn exactly what the BMW E36 CCV does, symptoms of pending failure, and I will explain how to replace it.
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What does the CCV do
The burning of gasoline in your engine causes combustion which forces the pistons in the engine to move up and down. The space between the engine cylinders and the pistons is very tight, but a small amount of gas is still able to escape. The gas escapes into the crankcase, and without the crankcase ventilation system, the pressure would increase to intolerable levels. The pressure would cause the engine gaskets to blow and cause lots of damage in the engine.
The CCV prevents this unfortunate event by eliminating the crankcase pressure. The CCV also removes oil vapor from the exhaust and recycles it back into the vehicle. Every car has some sort of crankcase ventilation, and these parts are absolutely essential to the proper functioning of the vehicle.
Symptoms of a failing CCV
Oil consumption is the most common and obvious failure mode of the CCV. What commonly happens in high mileage vehicles is that the internal component of the CCV (which is just rubber) will crack, and cause a pathway for oil and air to get through. The vacuum causes a rough idle and the oil will burn away in the cylinders, causing drastically increased oil consumption. If the valve severely cracks, you risk a scenario where the engine loses enough oil in a short enough amount of time where you may not catch it and the motor hydro locks.
Excessive smoking is another common symptom of a failed CCV. Typically the car will have heavy blue or gray smoke, this is a sign that oil is mixing with gasoline inside of the cylinders. If you notice your car has a heavy blue or gray smoke, the next thing to do is stop the car and check your oil!
Strange air sounds is another sign, as the Crankcase can make a considerable amount of noise when it goes out. There are a few cool videos on YouTube that depict a CCV that has gone out. With the car at idle the man attempts to remove the oil lid on the valve cover, the pressure is so high that he can’t even remove it. If you hear loud wheezing air noises, suspect the CCV.
The good news is that BMW e36 CCV valves are actually quite reliable. There is no recommendation to replace it until the 100,000-mile mark. Completely opposite of some of the newer model BMWs such as my mother’s X5. Her CCV blew out at 80,000 miles and then caused the valve cover gasket to blow, which eventually ended in a $1,000 repair. Needless to say, that car is currently for sale.
How to replace a BMW E36 CCV
Depending on the E36 you own, you may have a very different CCV replacement procedure than the one I outline in this article. E36 Inline 6 Cylinder Engines all have essentially the same crankcase and replacement process. However, the four-cylinder replacement procedure is different and has a different style crankcase. This replacement is a fairly simple job, however, it is absolutely crucial to the long term health of your engine to replace this valve.
I highly recommend that if you decide to replace the CCV yourself and you haven’t pulled the intake off before, go ahead and remove the intake manifold so you can replace all of the vacuum lines underneath as well.
There is also a temperature sensor that you will find on the intake manifold that is accessible after you remove the throttle body. I recommend replacing this, as you don’t need to do any additional work to replace it.
Finally, the idle control valve sits right beside the CCV, and is also replaceable without having to remove the intake manifold. If you want to spend the money on the part (ICV’s cost $150 – $250), it’s recommended to replace it as well.
BMW E36 CCV replacement procedure
I decided to replace my CCV after I replaced the valve cover gasket. I had to remove one end of the CCV hose, and saw that it was gunked up with yellowish oil. At first glance, this may cause instant anxiety at the chance that this may be a blown head gasket. Luckily, this is a typical symptom of a failing CCV, and when I removed the old one it was completely gunked up with yellow sludge.
- Remove the cruise control unit, and air box. Two 10 mm nuts hold the cruise control and air box in place, and two clips hold the air box to the MAF.
- Remove the intake boot and MAF, I typically just remove them as one piece, but you can remove them separately. All you need is a flathead screw driver.
- Depending on the year model E36, you may have an ASC throttle body, also called a secondary throttle body. If so, remove this first, it has two 10 mm bolts. Once this is removed, the main throttle body has four 10 mm bolts holding it to the intake manifold.
- If you still have your alternator air duct it will need to be removed, if you’re lucky it won’t crack into a dozen pieces (they are notoriously flimsy).
- No need to remove the hoses connecting to the throttle body, note the orange seal on the throttle body and make sure that you don’t lose it.
- Remove the hose running from the CCV to the Valve Cover, and disconnect the hose from the CCV to the Dip Stick. There are three bolts that hold the CCV to the Manifold, remove them.
- Get your hand underneath the manifold and take hold of the CCV, pull toward the engine block and the CCV should pop out of its seat in the manifold.
- The hardest part of this job in my opinion is removing the old CCV. It can definitely take some finesse. Some DIYer’s get it within a few minutes, and others take a bit longer. You need to tilt the CCV horizontally to get it through the manifold.
- Once you’ve removed the CCV, I highly recommend replacing the valve cover to CCV hose, and the CCV grommet.
- Installation is simply the reversal of disassembly, take care not to bang up the new CCV as you wiggle it under the manifold, and don’t forget to re-install the dip-stick hose.
BMW E36 CCV Replacement is a job that I would classify as well within the reach of most DIYers. Although, not a difficult replacement, it is very important to the reliability of your vehicle.
I highly recommend that while you are replacing the CCV, to take a look underneath the manifold and inspect the condition of the vacuum lines. If your vehicle is in the ballpark of my e36’s mileage (150k), it’s probably time to replace some vacuum lines.
During my replacement of the CCV I also noticed that the intake manifold gasket was shot, and I could actually see where it had broken in half. As a result of this the next DIY on my vehicle will be the intake manifold removal, as it is causing a vacuum leak.