Motor oil is the most critical fluid in your BMW’s engine, and if the wrong oil gets into the heart of the car, it could cause unwanted problems. But what is the correct motor oil to use, and what can happen if the wrong oil is put in your BMW?
BMW recommends that high-quality synthetic oil be used in all of their engines. If the incorrect oil is put in the engine, it can cause difficulty starting the engine, oil leaks, or a burning smell emanating from the engine bay. Using oil that is too thin can generate a ticking sound in the engine.
It is not ideal to use motor oil that is not approved by BMW. If the wrong oil does find its way into the engine without being noticed, this article will assist you in finding out what can happen. Read on to find out more.
What Signs To Look For If the Wrong Engine Oil Is Used In A BMW
There is plenty of information concerning the importance of engine oil. It can become overwhelming to decide on the correct oil for your BMW. If the incorrect oil is put in the engine, there are a few tell-tell signs that your car will display. If your BMW shows any of these symptoms, it might be a sign that it is not happy with its oil. Below are some of the warning signs:
Difficult Starting In Cold Weather
The cold weather causes the oil to thicken, and having oil with high viscosity may prevent the engine from starting. The thick oil is unable to lubricate the engine components. Thus, the engine parts’ friction is too high, and the starter motor can not overcome this resistance.
Be aware though, that a non-starting engine due to high viscosity oil only occurs in EXTREME cases, I’m talking you put 20W-50 (or higher) into a vehicle that takes OW-20.
Much more likely, you will notice more mild symptoms, such as your vehicle taking a little more time to start than normal.
Oil Leaks In The Engine Bay
If the wrong oil is being used on a high mileage or old engine, it may result in minor oil leaks appearing in and around the engine. This is caused by the different flow characteristics of other oils. An example of this is that synthetic oil is designed to flow into much smaller and tighter spaces than conventional oil.
Oil leaks will not cause any direct damage to the BMW’s engine, but they will leave an oily mess and a burning oil smell. If this is the case, keep an eye on the oil level in your BMW and top up when necessary.
Due to the fact that an older engine will have worn gaskets, seals, and therefore more areas for oil to escape, most professionals will recommend that you use a slightly higher viscosity (thicker) oil in high mileage vehicles.
Personally, I switched my 5W30 oil with 10W30 on my old BMW E36 and noticed within a week that I was losing less oil (old cars are always going to lose a little).
A Burning Oil Smell In The Engine Bay
Using oil with low viscosity in extreme conditions will cause the oil to break down and not thoroughly lubricate the engine. The high friction between the engine parts can give off a burning oil smell with no visible leaks around the engine.
The friction results from a lack of lubrication, which will cause the components to wear out quicker. A solution to this is to change the old oil with the correct recommended oil.
A Higher Fuel Mileage
If the oil in the BMW’s engine is too thick, the engine will not have the correct lubrication on the engine parts. This will result in the engine working harder than normal by using more gas to overcome the friction. If your BMW is using more fuel than normal, it could be that the wrong oil is in the engine. Do an oil change and monitor if there is a difference in the MPG.
A Ticking Noise Coming From The Engine During Startup
If a ticking or knocking sound resonates from the engine during a cold start. This could indicate that the oil in the engine is too thin. The ticking should dissipate after a few miles of driving, but the damage from friction will continue.
The best solution for this will be to do an oil change and see if the ticking sound has disappeared altogether; if not, there could be some bearings that may be damaged in the engine.
Another extremely common issue with BMWs (especially 3 Series) is the infamous VANOS “marbles in a can” sound. The BMW E36 and E46 were well-known for this problem due to deficiencies in the design of the VANOS.
The sound is caused by too much play between the cam gear and VANOS shaft. This issue can not be completely avoided in older vehicles, but using the wrong oil and delaying oil changes will speed up the degradation of your VANOS.
What Is The Difference In Using Conventional Oil And Synthetic Oil In A BMW
Motor oil is the most vital fluid in a BMW’s engine, and it is important to stick to quality oil. Buying the cheapest oil at your local O’Reilly’s will work just fine for your old Ford Ranger (I know, I do it all the time) but not for your performance-oriented BMW. BMW recommends that only synthetic oils be used in their car engines. It offers the best overall protection in its advanced engine designs.
Conventional oil was the oil of choice in the past, as it was inexpensive, which allowed for more regular oil changes. Some manufacturers suggested oil changes should be done every 3000 miles to keep the engine in excellent running condition. This is no longer the circumstance as technology has advanced to the point that synthetic oil changes only need to be done every 10,000 miles.
Conventional Motor Oil
Conventional motor oil is a reliable lubricant that has proven itself over many decades. The catch is that the oil will need to be changed much more regularly, as it loses its viscosity over time. This will lead to more service intervals over the engine’s lifetime, especially in hot climates.
Another issue that I have with conventional oil is that it leaves far more sludge in the engine. It ages dirty when compared to synthetic oil and unfortunately, that means that your engine will be left to deal with more deposits internally than it otherwise would be if you went with synethic.
Synthetic Motor Oil
Synthetic oil is superior to conventional oils, especially in the new modern high-tech engine of today. It has the benefit of being suited for use in most engines and offers longer-lasting performance. Synthetic oils have extra protection against foreign deposits in the engine. This is the reason that BMW uses synthetic oils in turbocharged engines.
Can Conventional Oil Be Added To Synthetic Oil In A BMW?
Adding conventional oil to existing synthetic oil in your BMW’s engine will not cause any harm, as long as the viscosity is suited to the environmental conditions. However, it is not recommended to mix the two types of oil. The most significant disadvantage is that the engine will not have all the protection synthetic oils offer.
Suppose the BMW’s engine needs to be topped up with oil (1 quart), and only conventional oil is available. In that case, it will be acceptable to add it to the engine. It would be recommended to do a complete oil change within 1,000 miles after the oil has been mixed to ensure the engine gets the best protection.
Conclusion
Using the wrong oil in your BMW can cause difficult cold starts, oil leaks, and higher gas mileage. If any of these symptoms happen to your BMW, change the oil and filter. BMW recommends using only quality synthetic oils in their engines as they offer the best lubrication protection.
It does not matter which quality oil you use in your BMW’s engine or if you might mix different oils together. As long as the correct viscosity is being used for the specific climate that the vehicle will be subjected to. The oil is vital to the longevity of an engine, so take care to use good quality synthetic oil.
References
https://www.bmwusa.com/center-services.html
https://www.mobil.com/en/sap/personal-vehicles/car/recommended-for-your-car/bmw