When it comes to internal combustion engines, everyone knows that air and fuel are the most critical substances required to make them work. Behind the scenes, however, the engine oil pump works to circulate another crucial substance – the motor oil.
When the oil pump becomes faulty, you’ll notice some common symptoms, such as the oil pressure dropping or the engine overheating. If you hear noises coming from the engine’s valve train or the oil pump, or if your car won’t start at all, that’s almost like the death sentence of the engine oil pump.
Shut the engine off immediately and troubleshoot the pump when you notice these signs.
In this guide, you'll learn to spot a bad oil pump in your vehicle. More important that that is that you'll know how the oil pump becomes faulty, so you can prevent it from getting rooted.
So, let’s get going.
How Do You Know You Have a Faulty Engine Oil Pump?
The oil pump in your car is responsible for circulating motor oil, which is critical in keeping your engine’s moving parts working correctly. So, recognising the signs when an oil pump goes bad is key.
5 Symptoms of a Bad Oil Pump
1. Drop in Oil Pressure
The engine oil pump is responsible for pressurising the entire oil system. So, a drop in oil pressure is the first sign of a problem.
However, most cars don’t have an oil pressure gauge. Your vehicle will likely have an oil pressure warning light or indicator instead.
The light is in the shape of an oil can. When it turns on, that’s a sign that you should stop driving immediately to prevent any further damage to your engine.
You can troubleshoot the oil pump at home or have someone tow your car to a workshop. Whichever way you choose to do it, don’t drive the vehicle. A compromised oil pump puts the entire engine at risk.
2. Engine Overheats
Next, a faulty oil pump will also cause the engine to overheat.
You see, motor oil protects your engine in two ways. Firstly, it reduces friction between the engine’s moving parts, reducing heat. The oil also absorbs plenty of heat as it travels throughout the engine.
When the oil pump fails to circulate motor oil as it should, the engine will quickly overheat. Sure, the engine has a separate cooling system (i.e., the radiator and other parts). Still, the excess heat will certainly overwhelm that system’s cooling capacity.
This is another reason you must stop your car immediately once you notice signs of a faulty oil pump and have someone tow it to a workshop.
3. Noise from the Valve-Train System
A failing oil pump is the first piece that causes a chain reaction, leading to several harmful side effects. Aside from overheating, the engine’s moving parts will also experience a lack of lubrication. That will produce another symptom for you to notice – loud noises.
For starters, you’ll hear noises coming from the valve-train system. That’s the engine part that includes hydraulic lifters, pushrods, valve guides, and other moving parts.
When there’s not enough engine oil flowing through to lubricate those parts, they’ll start to grind against each other noisily. When you hear these noises, you must shut your car off immediately.
Those noises are the least of your problems. However, as the engine continues running, the metal parts will scrape against each other and damage the engine from inside. That will lead to even more extensive (and expensive!) repairs.
Again, shut the car off and get someone to tow it to the workshop immediately.
4. Noise at the Oil Pump Itself
Of course, a problematic oil pump will make noise itself. However, most drivers won’t notice this noise unless they look for it. That’s why the noises in #3 are often the first symptoms that drivers notice.
If, by some chance, you're inspecting your engine compartment and hear noises coming directly from the oil pump, that's an early sign that the part is failing.
You'll hear whining or whirring sounds because its internal moving parts are wearing out. You'll hear these sounds even when the car is idling.
Let’s be clear – the oil pump isn’t meant to make any noise. So, if you hear something, troubleshoot, and replace it as soon as possible.
5. Car Won’t Start
In the most severe cases of an oil pump failure, your car won't start at all. None of its parts can move, so the combustion process cannot occur.
At this stage, you’ll have no choice but to tow the vehicle to a workshop. Aside from replacing the oil pump, the mechanic will also have to thoroughly inspect the engine for any other damage signs.
What Causes Oil Pump Failure?
You can trace the root cause of an oil pump failure to the pump itself or the oil you've put in it.
2 Main Causes of Engine Oil Pump Going Bad
1. Oil Pump – either damaged or incorrectly installed
Firstly, an oil pump will fail if you’ve installed it incorrectly. You’ll know that’s the most likely cause if the oil pump is faulty after a recent installation or replacement.
Small mistakes like incorrectly shimming the pump or not giving the pump gears enough backlash can cause the pump to fail when you use it.
However, if you haven't touched the pump in a long time, it's likely faulty from a lack of maintenance. Oil changes are crucial because the oil picks up debris as it flows through the engine and sludge builds up in the pump.
As the build-up worsens, it strains the pump and eventually causes it to fail.
2. Motor Oil – irregular oil change, contamination, low oil level
The oil that goes into the pump is just as essential. As we saw above, infrequent oil changes will cause a sludge build-up in the pump. Not only that, but the oil will also go bad and worsen the problem.
The same problem can also happen if contaminated oil circulates in the system. That contamination can occur in many ways, such as when you’re pouring the oil into the system.
Lastly, a lack of oil will also cause the oil pump to fail. When the pump doesn’t have enough oil, its internal parts will grind against each other and damage the pump from within.
Can You Drive with a Bad Oil Pump?
No, you cannot drive with a bad oil pump. There are two reasons why doing so is a terrible idea.
- Firstly, a faulty oil pump can’t circulate oil to lubricate your engine’s parts. So, when you keep the engine running without enough oil, its metal parts will grind against each other and damage the engine from inside.
- Secondly, the lack of circulating motor oil will cause the engine to overheat, causing damage to the engine.
So, as soon as you realise you’re experiencing bad oil pump symptoms, shut the engine off and get someone to troubleshoot it immediately.
To learn more about engine oil pumps and other car parts, check out the blog at Carpart.com.au. There are plenty of educational blog posts to help you understand what’s going on with your car.
By Ray Hasbollah