An oil leak in a BMW isn’t a new or unique problem and has been one of the most common issues in BMWs for a long time. Keeping your engine oil in check is important to keep your BMW’s engine safe. But what if you need to drive your BMW with an oil leak?
You can drive a BMW with an oil leak depending on the source of the leak and how much oil your engine is losing. Driving a BMW with a small oil leak might not be a problem if you are taking it to the mechanic or you have a very small leak. However, driving it without checking the source of the oil leak and getting it fixed can lead to hazards like a damaged engine, engine fire, or potentially a car crash.
What should you do when you notice an oil leak from your BMW? If you are interested in learning the risks, causes, and solutions of an oil leak in a BMW, you are in the right place. So, let’s learn everything about oil leaks in BMWs!
Risks of Driving a BMW With an Oil Leak
Driving a BMW with an oil leak can damage your engine but it depends upon the level of available oil. If the level of oil on the dipstick comes out to below the minimum marker, you should first add oil and second get the vehicle to where you can park it and assess how quickly the engine is losing oil.
| Problems Related to Oil Leak in BMW | Cost of its Repair |
|---|---|
| Seized Engine | $3000-$6000 |
| Engine Repair | $2500-$4500 |
| Fire/Explosion | Irreparable |
| Replacement of hoses | $150-$450 |
| Oil leak fix | $100 - (depends on the source) |
It can be dangerous to drive a BMW leaking oil when you don’t understand the root cause of the issue. There’s even a chance of your vehicle catching fire if the leaked oil drops onto the exhaust. We are sure you never want that, so why risk it?
Some of the major risks involved in driving a BMW with an oil leak include:
- Deterioration of engine compartments and engine seize
- Fire and explosion in the engine
- Hefty bills from a large engine repair
- Wear of other nearby parts
- Car crash from losing control over the vehicle
Let’s learn about these risks in detail now!
Wear of Engine Parts
Unattended oil leaks overtime can cause significant wear and tear on various engine components under the hood. Running a BMW with low oil for even a short amount of time can cause damage. Engine oil serves several purposes in a BMW.
Not only does oil keep the internal engine components lubricated but it also plays a part in maintaining keeping the engine from overheating. You might typically think that this job is chiefly completed by radiator coolant but oil plays a significant role in engine temperature by transferring excess heat. Oil plays an even bigger role in maintaining BMW engine temperatures because of the excessive amount that these vehicles take. BMWs take a lot more oil to fill up than most other vehicles. One of the rationales for this is that the larger oil capacity aids the coolant system in keeping these high performance vehicles from overheating.
Ignoring a small oil leak can lead you to a hefty repair that can cost you a lot, especially in a BMW. Not only this, the entire engine can gradually decline and stop working altogether.
Fire in Engine
While this is not a common hazard from a small oil leak, there is always a risk that an oil leak can be ignited from coming into contact with hot metal. BY FAR the most common source of an oil leak that causes smoke or fire is a leaky valve cover gasket. We will discuss valve cover gaskets further below.
Damage to Rubber Parts
Unchecked oil leaks have a habit of reaching all kinds of areas within your engine bay. Leaking oil can cake rubber hoses overtime. Accumulated layers of oil typically will not give your transmission or fuel injector hoses much trouble, but rubber coolant lines are far less durable and can prematurely fail due to being caked in oil. Oil leaks can affect the lifespan of various parts such as the hoses and rubber seals.
Car Crash and Explosion
Car crashes and explosions are thankfully very rare and are rarely ever due to an oil leak. That being said, too little oil will cause various components within the engine to have too little lubrication. The worst scenario here is that the engine “seizes up”. An engine seizes up when the metal components begin to rub against each other due to a lack of oil. There are different ways that an engine can seize but essentially they are all typically due to overheating and a lack of lubrication in the engine due to low oil.
An engine seize while you are driving can be a very dangerous situation. This is why it is so important to get a sense of how quickly you are losing oil when you notice that there is a leak.
Environmental Hazards
The leaking of oil is damaging to the environment. Oil is an environmental pollutant that can get in the drains and contaminate water reservoirs. It can cause a lot of water pollution and harm plants and animals.
Moreover, your driveway can get quite dirty with an oil leak. Oil is a stubborn liquid and you probably don’t want your garage to be completely stained in old engine oil. That being said, if you are something of a gearhead like I am, an oil-stained garage floor is kind of par for the course.
Common Causes of Oil Leaks in BMW
To fix an oil leak in a BMW, you must know what causes the oil leak. When you know the reason behind the oil leak, you can avoid it in the future and save your BMW from further damage. Let us start off with some of the most common oil consumption issues that you are likely to have on your BMW and then we will move on to more infrequent issues that may arise.
Valve Cover Gasket
The valve cover gasket leak is by far the most common oil leak you will see in a BMW engine. All rubber gaskets fail eventually, but the valve cover gasket can be particularly problematic in a BMW. The gasket is easily identifiable, as it sits at the top of the engine between the valve cover and the engine head. Overtime, the rubber gasket begins to harden from the engine’s heat. Eventually, it will become brittle and begin to leak oil.
Here’s a great video on diagnosing a valve cover leak.
A bad valve cover gasket is also fairly easy to identify, as oil will commonly leak (slowly at first) down the side of the engine. Another common symptom is smoke. Engine oil leaking from the valve cover gasket can leak onto the exhaust manifold, causing smoke to emit from the engine bay. If you see smoke coming from under your hood, stop the car, the oil can ignite and start a fire.
The good news is that valve cover gasket replacements are typically well within the skill-range of even most beginner DIYers. I have done this job dozens of times and it typically will take less than an hour to complete. That being said, some BMW valve cover gaskets such as the BMW X5 are extremely difficult to replace. Be aware of the replacement difficulty associated with your model BMW before you decide to take this job on.
Oil Pan Leak
An oil pan serves a relatively self-explanatory role, it stores a large amount of oil at the bottom of your engine. Your engine oil pump is also located at the bottom of the engine and you have to remove the pan to replace the pump. Luckily, the pumps rarely go bad, however, your oil pan is a different story. BMW oil pans are sometimes damaged overtime due to debris and stones, his simply is due to the pan’s location at the bottom of the car. It is also one of those parts that is most likely to puncture after an automobile accident.
The oil pan gasket is another extremely common source of BMW oil leaks. This gasket is very large but is extremely difficult to get to. Most BMWs will suffer an oil pan leak once they hit a certain age, but the good news is that this gasket rarely leaks enough to be considered a significant problem. In fact, every BMW I have ever owned has had a small oil pan leak and none of them were ever serious enough to warrant the amount of time and money it would cost me to replace the gasket.
Drain Plug Damage
The drain plug is typically at the very bottom of the engine on the passenger side. It is used to drain old used oil. In the process of changing oil, the drain plug can be damaged and this will lead to an oil leak. Drain plugs also have gaskets on them (either copper or rubber) and they are designed to be replaced after every replacement. Some times people re-installing the drain plug will fit it on too loosely and this will also cause an oil leak. My dad actually make this mistake when he was a teenager and his engine locked up as a result!
Worn Out Seals
One of the more frightening sources of oil leaks in old vehicles is a leaky rear main seal. The rearLuckily, BMWs rarely have a problem with rear main seals. TheThe seals that cover different components of your engine protect fluid and oil from escaping. Seals or valves are also available in the gaps of the pressurized system. With time, these seals can wear out or crack thus releasing oil from the engine.
Installation Mistakes
While changing engine oil, make sure to tighten the oil reservoir cap down. That plastic cap might not look like much, but it needs to be tightened fairly well before it becomes water-tight. Otherwise you will have oil pouring out of the sides of your oil reservoir.
Using the Wrong Oil
Using the wrong oil can be another cause of oil leaks. Always check the recommended oil for your particular BMW. BMW recommends 5w30 for many of its vehicles but many models also have a range of tolerances. Typically, you want to consider using slightly thicker oil as your BMW ages. Thin oil such as 0w30 and and 5w30 is an excellent option for lower mileage vehicles because the rubber seals and gaskets are still in great shape. But as your engine’s rubber components become more brittle, you will want to consider moving to a thicker oil such as 10w30.
How to Fix an Oil Leak in a BMW?
I’m not going to dive into detailed step-by-step DIYs as that is beyond the scope of this article, but I will cover some general tips and easy fixes you can apply if you have an oil leak problem. If you are unable to determine the source of your BMW’s oil leak, the best thing to do is have a mechanic diagnose the problem for you. Always stick to indy mechanics that have some actual experience with working on BMWs.
Every vehicle is going to have an oil leak eventually, but here are a few tips to help avoid the frequency and severity of them:
- Change your oil frequently as suggested.
- Don’t avoid small oil or fluid leaks, identify the source and make an educated determination about whether this is an immediate fix problem or a do-it later problem.
- Replace your oil caps with new ones once they become loose.
- Go to a mechanic that frequently handles BMWs for your oil changes if you don’t feel comfortable doing it yourself.
Gaskets and Seal Repairs
Older BMWs will typically have more than one oil leak at a time. This is simply par for the course in owning a BMW with some miles on it. While it is typically unnecessary to fix every leak (in fact at a certain point it becomes nearly impossible!), there are some products that offer easy, quick fix solutions to oil leaks.
With that being said, I have used used quick-fix oil sealants before. They are not a magical cure-all but they do have their place. I would never recommend one of these products if you have a leak that can be easily fixed such as a valve cover gasket, vanos hose, CCV valve, etc. On the otherhand, if you have a blown rear main seal or an oil pan that is dumping oil, these quick-fix sealants are cheap, fast, and are typically well-recommended.
Some of my favorite quick fix oil leak sealants are:
- Seals timing cover, cam seal, rear main and other hard to stop oil leaks
- Add to engine oil
- Specifically designed to seal rear main leaks, but also works better than a conventional stop leak on all other leaks
- Add entire bottle of Rear Main Seal Repair to engine crankcase (where you add oil) at or between oil changes. Do not overfill. Most leaks will stop within 100 miles or 2 days of driving
- Professional strength fast acting resealer, stops leaks fast
- Rejuivinates all rubber seals & gaskets in engines, transmissions, power steering, differentials and hydraulic systems
- Compatible with conventional and synthetic oils, ATF, gear oil, power steering fluids and hydraulic oil
- Does not contain petroleum distillates, will not over-swell or breakdown seals
- 8oz bottle will treat a 6 quart capacity, adjust accordingly
All you have to do is add the indicated amount to the oil and you are good to go. These quick-fix solutions are not guaranteed to resolve an oil leak, but I have found that they do often help significantly with hard to reach oil leaks.
Frequently Asked Questions
How Much Does it Cost to Fix an Oil Leak in a BMW?
The cost of an oil leak repair on a BMW varies significantly depending on the source of the leak. Is it a loose drain plug, reservoir cap or is it a VANOS leak? Is your valve cover gasket worn out or do you have a blown rear main seal? A repair can cost you anywhere from several hundred dollars to several thousand dollars.
How to Tell if Your BMW has an Oil Leak?
Look for the obvious signs such as:
- Indicator light
- Burning smell
- Sizzling noises from the engine
- Visible oil stains in the driveway
- Smoke from the hood
How to Know if the Car is Leaking Oil or Water?
The best way to check if your car is leaking oil or water is to dip a piece of paper towel in it. If it has a dark color and is thick to the touch, it is oil; otherwise, it is likely water. Water (coolant) also has a very distinctive smell to it, most people describe it as a “sweet” smell. Oil does not smell sweet at all.
Final Thoughts
You now have a solid overview of oil leaks in a BMW. There is a lot to look out for, but overall these are outstanding cars and even though they come with a little extra maintenance, for most drivers they are well worth it. Not every oil leak is a cause for alarm, but you should always do your diligence when you discover a leak. How much oil are you losing and where is it coming from? The answers to these questions will determine whether you can (a) ignore it, (b) take it to the shop, or (c) fix it yourself.