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As you’re well aware you have to look after your car’s engine as it’s the most expensive part of the car. If you’re hearing new noises coming from under the hood and haven’t checked the oil level recently you’re right to be concerned.

A tapping, ticking, or rattling noise are common signs that your engine oil level is low. The sounds are happening because there isn’t enough oil within the engine to lubricate its parts effectively. Topping up with oil will remedy this.

An engine knocking sound is rare when the oil level is low and this points more to a carbon build-up within the engine or out-of-sync timing.

That’s not the full story though!

The sound can be worse when you first start the car after it has been sitting for more than a few hours. This is because the oil will have completely drained to the bottom of the engine over this time.

When you start the engine, what oil you have in your engine is forced from the pan – the bottom of the engine – to the top part, where the pistons are working at very high speeds.

what causes a car to burn oil

A lack of oil in the engine will mean the pistons aren’t being lubricated and give off the metallic ticking or tapping noise that you hear.

Another part of the engine is hydraulic tappets. Depending on your car, there is a minimum of 16 fitted in your engine. These rely on good oil pressure to work efficiently.

When the oil level in the engine is low, one of the consequences is low oil pressure. When the pressure is low, they can also make a tapping noise.

Can Dirty Oil Cause Engine Noise?

Dirty oil is thicker than newer oil and can contain impurities such as metal shavings from the engine and sludge. You may notice noise when you first start the car as dirty oil may struggle to get from the pan to the head of the engine. Your oil pump may struggle to get the oil around the engine causing more wear than if you had new oil.

What Are the Signs of Low Engine Oil?

Oil Pressure Warning Light Is On

Low oil and engine warning light

This is the main sign of having a low oil level in your engine. Although it’s an oil pressure warning light, the main cause of low oil pressure is the engine having a low amount of oil. The two issues are very closely linked.

Your car’s oil pressure light should go off soon after you’ve started your car. If it remains on then, this indicates a problem.

Check Engine Light Is On After Oil Change [CAUSES AND FIXES]

Even if the light does go off, it might come back on again as you’re driving. Sometimes a sharp turn left or right can be enough to disturb the level of your oil when it’s low and cause the warning light to come on briefly.

An Overheating Engine

Car engines are generally cooled by water, but some by air – like the VW Bug. These systems can only take away the heat that the oil has collected in the engine.

Not only does engine oil lubricate, but it also takes absorbs the heat caused by friction in the engine. If there isn’t enough oil to do this sufficiently then, the engine can overheat. It won’t matter if the coolant system is working well if the oil can’t pick up all the heat generated by the engine.

Poor Performance

A low oil level can affect how well the engine performs. If there is added heat friction and wear on the engine parts, they won’t work to their maximum. 

Generally, though, you won’t notice a large drop-off in performance until your engine is beyond repair. There are plenty of signs that your oil level is low to take notice of before this becomes an issue.

What are the Causes of Low Engine Oil?

Oil Leaks 

Some car manufacturers state that losing a small amount of oil over time is normal. 

However, if you’re noticing a large drop in your car’s oil level regularly, then these may be the causes.

As a basic rule, most cars that have traveled less than 50,000 miles in their lifetime shouldn’t be burning oil between oil changes. 

As cars get older, piston rings and other engine parts will allow a small amount of oil leakage. Often so small that you won’t really notice it. There’s unlikely to be a pool of oil underneath your car on the drive.

If you see blue smoke coming from your exhaust, this is a sure sign that oil is leaking into the combustion chamber of your engine and being burned off with the gasoline.

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When To Change the Engine Oil in a Car

Most car manufacturers recommend that cars have the oil changed every 5,000 to 12,000 miles. Some newer cars with engines lubricated by fully synthetic oil can go 15,000 miles without an oil change.

What Happens if Your Engine Oil is Low?

Damage to Engine Parts

Your engine will eventually fail. It will get too hot and cause intense heat that will warp parts and cause catastrophic failure. 

Engine Oil Will Degrade Quicker

Engine oil does become less effective over time. It loses its ability to absorb heat. 

The less oil in your engine, the quicker it will deteriorate as it has to take work harder than it was designed to do. 

What could have been a simple case of topping up the oil now becomes a complete oil change.

As it deteriorates, it will produce sludge that can cake the pistons and cylinder walls, resulting in poorer performance. 

Can You Drive With Low Oil?

No. Low oil will definitely damage your car’s engine. It would be best to stop driving, turn off the engine, and top the level up.

Can I Top Up Rather Than Change The Engine Oil?

An engine oil top-up should not replace an oil change. Sometimes the oil level will drop between oil changes, and it’s okay to top up. However, to do this when an oil change is due is a bad idea. Oil eventually goes bad, and two factors dictate when this happens. 

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Age of The Oil

The older a car’s oil is, the less effective it will be. If a car isn’t doing many miles and hasn’t been changed for a while, some people believe it can still be okay after a couple of years. This is not advisable. 

The shelf life of oil can be anywhere up to 5 years but once opened; most manufacturers state it’s good for one year only.

Miles Driven

If you have been keeping to the car manufacturer’s oil change recommendations and notice your oil level is low, you are safe to top up the level. One word of caution is if you’ve noticed a significant drop, it might mean that you have a serious oil leak. 

It’s normally advised to change the oil filter at the same time as changing the oil. Continually topping up the oil level with an out-of-date failing filter won’t prevent debris and sludge from reentering your engine.

The 5 Reasons Your Cars Engine Oil Is Black After Being Changed

It’s a good idea to make a few checks like exhaust blue smoke or oil leak around the cover gasket to make sure all is well.

Can an Oil Change Help With Engine Knock?

It is possible but unfortunately not likely. A knocking noise rarely indicates low oil levels, but it can also signify a more damaged engine.

If a car’s low oil level isn’t topped up quickly enough, the tapping noise you’ve been hearing can move onto a knocking noise. This indicates that engine parts have failed and will need replacing. 

Topping up the oil level may initially mask the knocking noise, but it won’t fix the damage that’s already been done to the engine.

How Much Will it Cost to Fix an Engine Knock?

Expect to pay anywhere from $1,000 and $3,000 to replace the damaged parts. Often seals, head gaskets, and sometimes a complete head need to be changed over. Labor costs are high, too, as the engine has to be stripped down and rebuilt. Expect labor to cost between $500 and $1,500.

In Summary

  • It’s not normal to hear tapping or ticking noises coming from your car engine. These noises are signs that your oil level is low.
  • Just because the low oil light hasn’t come on doesn’t mean the oil level isn’t low. These warning lights can fail.
  • It’s not good to drive with low oil in the engine as you can cause expensive damage that could have been prevented.
  • An engine knocking noise probably means that there is more significant wear in the engine. A top-up may lessen the noise but not rectify the underlying problems.
  • Oil top-ups are okay as long as it isn’t more than a year since you had a complete oil change or driven more than your car manufacturer recommends.

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In Conclusion

Your engine oil may be low if you hear tapping, ticking, or rattling sounds. The engine’s inability to efficiently lubricate its components is the cause of the noises.

When the oil level is low, an engine knocking noise is uncommon, and this is more indicative of carbon buildup inside the engine or out-of-synch timing.

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