Diagnosing Noises in Your Car
This video covers a lot of the basics when it comes to finding the source of a noise. You might find that having a friend help you with this process can really make things easier.
I list this topic first because it’s probably the most common. Some engine noises are normal; others can mean your engine is about to come apart. It’s important to decide what category your noise fits into.
The engine noise that’s the most concerning is a knocking noise. Knocking noises can mean loose parts inside the engine. Loose parts inside the engine can cause catastrophic results. The knocking noise I’m referring to here has a slow frequency; it’s not a fast noise, but more of a rhythmic thump at idle, which increases with engine speed. This noise might also coincide with a blinking oil light on the dash.
If this is the case, you likely have loose engine parts that need to be serviced or replaced. Many people see this as an oil pump problem, but this is incorrect in most cases. Oil pressure is actually created by the clearances between engine parts. If that clearance becomes excessive, you will see a drop in oil pressure. Oil pumps create a volume of fluid, not pressure. It’s the resistance to that flow that creates the pressure. With your engine, that resistance is created by the clearances between the moving parts. Here’s a video that will help explain what I’m talking about.
A knocking noise from your engine can also mean that you’re low on oil. One of the first things to do if you hear a noise from your engine is to check the oil level and condition. If the oil is low, top it off and recheck for your noise. If it goes away, consider yourself lucky, but be on notice. If your oil was low, there is a reason. It could mean you have a leak, or it could mean that your engine is burning the oil in the combustion chamber. Either way, it’s a situation that should be monitored closely. An engine without oil, especially one that’s making noise, is not long for this world. I usually keep a spare quart or two of oil in my vehicles to deal with this very scenario; I would suggest you do the same.
As long as we’re on the subject of oil and engine noises, let’s talk about oil viscosity. Oil viscosity is the rating used to measure how a fluid performs under a variety of conditions. The people who engineered your vehicle spent a lot of time and effort figuring out the perfect viscosity of oil for your engine. Usually, they print it right on the oil cap itself. If you don’t see it there, check your owner’s manual.
Many people tell me they’ve put thicker oil in their engine because they live in a warmer climate, or they feel it will quiet a noisy engine or keep it from burning oil. I disagree with this line of thinking. Your car’s engine has a recommended oil viscosity for a reason. I strongly urge you to stick with that recommendation to avoid further damage to your engine. It is true that some manufacturers list oil viscosities for different temperatures. If this is the case, by all means use the correct oil for your climate. If you don’t have such a listing, stick with what’s on the oil cap or what the owners manual says. Avoid going off the reservation here, you could get yourself into trouble if you put the wrong viscosity oil in your engine. Thicker oil takes longer to reach the top end of the engine. As a result, the top end of the engine gets starved for oil during start-up or colder conditions. Once this happens, wear sets in, and then there really is no turning back. If your engine is on its way out anyway, go ahead and put the thicker oil in. You know you’re going to have to replace it anyway. However, if you feel more qualified than the engineers who made your vehicle, more power to you.
One last thing on engine noise and oil. If you just changed your oil, perhaps with a different brand, with synthetic for the first time, or with a different viscosity than what was called for, and you now have a noise, you’ve found your problem. What this situation is telling you is that what you just put in isn’t working. I would recommend you drain out what you put in and replace it with what should be in there, and recheck for your noise.
Here’s an example of an engine that was making a noise. Shortly after this video was made, this engine threw a connecting rod, which destroyed the engine.
Using synthetic oil in your engine is a GREAT choice. Synthetic oil does a much better job in your engine than conventional oil. You need to be cautious though. In some cases using synthetic oil can actually cause your engine to start making noise where it didn’t with conventional oil. This is due to the different characteristics that synthetic oil has. Because synthetic oil is so much better than it’s conventional counterpart, it can actually cause a noise where there wasn’t one before. If you have an older engine that’s likely worn out, meaning it has excessive or borderline bearing clearances, synthetic oil will slip right through that opening and possibly cause engine noise. I’m not saying this will happen if you use synthetic oil in an older engine. What I’m saying is that sometimes this will happen in older high mileage engines, and when it does, switch back to regular oil and see if the noise goes away. If it does, at least you know what the issue is. I’d be saving my money for a new engine or new vehicle if this is the case. It may not be long before the engine fails if it’s making noise. Here are a couple of videos I’ve done on this topic that might make things a little more clear.