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More often than not, the cheaper, seemingly less significant parts of your vehicle cause bigger, more expensive repairs in the long run. In the last few articles, we saw how more affordable parts like spark plugs and ignition coils can cause engine backfires and misfires. Today, we discuss six of the most evident clogged oil filter symptoms.
Why a clogged oil filter is bad for your engine
An oil filter filters dirt and dust from the engine oil. Although the oil filter cleans the oil, the dirt and dust stay inside the oil filter—it cannot and does not throw it out. The oil filter can store dirt and dust to some extent, but after that, replacing it is absolutely necessary.
The bypass system becomes active when the oil filter is clogged, and unfiltered oil starts running through the engine. The bypass system is designed to keep the engine oil flowing even when the filter media is clogged.
The problem is once the bypass system is active, the engine oil is no longer filtered. It means more friction between the engine parts, which results in faster wear and tear.
In this article, we go through the different symptoms of a clogged or faulty oil filter.
6 Symptoms of a clogged oil filter
An oil filter should be changed at least once every 10000 km or at manufacturer-recommended intervals. Ideally, oil filters are changed at every oil change to ensure the longevity of the engine and the oil. Skipping a replacement will not damage your vehicle instantly. But if it gets clogged enough to bypass the oil, the friction can damage your engine components.
Here are six signs of a dirty and blocked oil filter:
1. Drop in engine oil pressure.
A drop in engine oil pressure is one of the direct signs of a clogged oil filter. Maintaining the optimal engine oil pressure is necessary to ensure proper cooling and lubrication of all moving engine parts. Most vehicles today have an oil warning light on the dashboard. If it is illuminated, it’s a good idea to pull over at the nearest auto shop. Even better—pull over and call for a tow.
Oil filters have a bypass valve to keep the oil flowing through the engine in case the oil filter is clogged. A spring holds the valve in position, and when the oil pressure inside the filter increases, the valve opens up. Once this happens, the unfiltered oil starts flowing freely into the engine, and the oil pressure drops.
Not all cars are fitted with a pressure sensor, so if you don’t have an oil pressure warning light on the dashboard, you might have to check the pressure manually. Also, the oil pressure warning light can illuminate when the oil pressure is high as well—which, most of the time, is a sign of a broken pressure relief valve.
2. Engine overheating.
This one is from my own personal experience—the engine can overheat just because of a clogged oil filter. And if you fail to diagnose it, you might end up spending thousands on other engine parts, just like I did.
For me, the overheating due to a clogged oil filter was resulting in engine misfires after a hundred miles or so. I had to turn the engine off for at least half an hour to get going again. It would go as if nothing happened for another hundred miles, and then it’ll start misfiring again. But misfiring due to overheating was common in older carburetor vehicles; the only question was what was causing the overheating.
As mentioned earlier, when the oil filter is clogged, the bypass valve opens up, and the oil starts flowing freely through the engine—along with the dirt and dust. That results in improper lubrication, which is the recipe for engine overheating.
So, if your engine is overheating, have your oil filter checked before you move on to replace expensive parts. It might save you a few grand.
3. Knocking sound from the engine.
A knocking sound from the engine can also be one of the symptoms of a dirty and blocked oil filter. Aftermarket oil filters with different specifications to the stock filter can alter the engine oil pressure. It can lead to engine knocking, but a severely clogged filter can also be the reason behind the knocking.
When the filter is clogged, and the bypass system is active, the dirty oil causes rapid wear of the camshaft, also known as the cam effect, which produces knocking sounds in the engine.
It is not necessary that the engine knocking is due to a clogged filter. But you must get it checked and repaired before it gets too bad. Engine knocking almost never ends up well.
4. Sputtering engine.
The sputters are more likely to be because of more severe problems, but at times, it can also be due to a blocked oil filter. The sputters are literally the sound of engine damage, telling you that it is not able to run properly. It often starts as indistinct ticking sounds, gradually turning into more violent sputters.
When the filter is clogged, it sends unfiltered, sludge-worn oil into other engine components, causing them to splatter the oil. Yes, sputters are less likely to be due to a clogged filter, but any sputters or metallic noises from the engine should never ever be ignored.
5. Poor performance.
The drop in engine performance due to a clogged filter is hard to notice since it is slow and gradual. But it does make a significant difference over time, and noticing the performance drop often goes, ‘my car wasn’t like this before.’
As the bad engine oil increases friction between moving parts, the engine will lag and struggle to operate. You’ll notice a reduction in the engine’s ability to accelerate and produce power.
But yeah, poor performance can be due to a number of reasons, ranging from a clogged fuel filter, air filter, or carburetor to ignition system problems.
6. Dark exhaust smoke.
The exhaust smoke can turn dark due to a clogged oil filter. You shouldn’t see smoke coming out of the exhaust, except for some white smoke during cold starts. If you see dark smoke from the exhaust, your vehicle might be burning fuel or oil.
When the filter is clogged, the dirty engine oil can get leaked inside the tailpipe. The smell of burning oil is so strong that you can easily tell if it is burning fuel or engine oil. You may also find oil leaks on the ground if the filter is severely clogged.
Blocked oil filter: Frequently asked questions
What causes a clogged oil filter?
The engine oil itself causes a clogged or dirty oil filter. The oil gets dirty since it lubricates and flows through the moving parts of the engine. It then goes to the oil filter, where filter media collects all dirt, resulting in a clogged oil filter over time. However, if the oil filter is replaced on time, the filter will not get clogged.
What are the symptoms of a clogged oil filter?
The signs of a clogged oil filter range from a drop in engine oil pressure to engine overheating and sputters. You may also notice a knocking sound from the engine, a drop in performance, or dark exhaust smoke.
What happens if you drive with a dirty oil filter?
If you keep driving with a dirty oil filter, the bypass system of the oil filter becomes effective. Once that happens, the oil is no longer filtered, so dirty oil starts flowing through the engine. This increases friction between moving parts of the engine, resulting in faster wear and tear. Ultimately, using a dirty oil filter for an extended period of time results in expensive engine repairs.
Can a clogged oil filter cause a loss of power?
Yes. As a clogged filter bypasses the engine oil, the dirty oil starts flowing through the engine, increasing friction between moving components. More friction results in the engine having to work harder, which means a loss of power.
How do I know if my Oil Filter is clogged?
If you notice engine overheating, loss of power, sputters from the engine, or a drop in engine performance or oil pressure, your oil filter might be clogged. You can also check your oil filter every 5000-7000 miles to see if it is clogged.
What to do when the filter is clogged?
Well, there isn’t much to st replace it with a stock oil filter or one from one of the best oil filter brands like Bosch or Wix. When going for aftermarket filters, make sure it fits your engine and can maintain the manufacturer-recommended engine oil pressure.
Also, replace the engine oil and filter at manufacturer-recommended intervals. It goes a long way in keeping your engine healthy.