Running on Empty: How Low Oil Levels Can Cause Your Car to Overheat

(Last Updated On: May 8, 2023)

You’ve got an overheating engine, and the oil light just came on “can low oil cause overheating?” will undoubtedly cross your mind.

To get straight into it before we go any further, low oil can cause overheating. Engine oil’s job is to lubricate the engine components without much oil to provide lubrication, you get friction, and friction means heat. Although your engine won’t melt, heat causes stress on components in the engine and forces the cooling system into overdrive, trying to keep the temperature down. Which ultimately can cause those parts, such as the water pump and thermostat, to fail quicker.

Although, as mentioned, low oil can cause overheating, it is rare. The oil, just a tiny bit low, will hardly cause any problems and require an oil change or topping up. But dangerously low oil is more likely to cause the engine to seize or another component to fail. Overheating can result from low oil, but it needs to be just the right amount to cause no damage to engine internals. If you find the oil pressure light, low engine oil light, and the temperature gauge shooting up, you can say the cause is low engine oil.

Why does low oil cause the engine to overheat?

Engine oil has two main jobs. Number one, lubricate engine components to reduce friction between the components.

Number two, cool moving parts. Engine oil cools moving parts by moving the heat through to the oil cooler, a much smaller radiator that allows flowing air to pass through as you drive, cooling and removing the heat.

If the engine oil is low, lubrication is not provided. Thus, there is friction between components. Friction produces heat. Then because the oil is low, there is less fluid to move the heat to be cooled. The engine’s little oil can’t keep up and never cools sufficiently. This is where an engine’s coolant system tries to help by removing the heat from the engine bay. However, this is designed to remove the heat when all components, including the oil, work correctly, so when one-half of the engine is not doing its job, the coolant system is going into overdrive trying to pick up the slack. It can’t cool the engine enough on its own.

What are the other issues of driving with low oil?

Overheating is not the only problem when driving low on oil, especially when driving long term with the car underfilled on engine oil. The other issues include

Engine oil has additives such as corrosion inhibitors. When you drive low on oil and start overheating, it degrades, and all of the qualities in the oil are destroyed. Something as simple as oil can write off an engine, leading to a hefty repair bill. The expense of just topping up the oil, even with just a liter of oil, will stop all of these issues, so driving low on engine oil shouldn’t be a thing, but it does need regularly checking to avoid such problems.

How long can you drive low on oil?

Checking the oil level before considering if it is safe to drive would be the only way of determining how far or if you can drive. No oil on the dipstick will tell you that you shouldn’t even bother starting the engine it is too low and more damage can or may already have been done.

However, if the level is still on the dipstick but not quite enough to reach the minimum marker, it would be ok to drive but only a brief journey to an Autopart store/garage for a top-up or replacement.

check engine oil level

Can old oil cause engine oil to overheat?

Old engine oil is no more likely to cause overheating than new oil. Although, depending on what you call old oil would also depend on how ‘impure’ the oil is and how good it is at doing its jobs. Old engine oil oxidizes, which causes the engine oil to turn into sludge, the same as driving with too much engine oil causes oxidization. There isn’t much you can do to prevent oil oxidization which is why the engine oil is replaced at regular service intervals.

The only way old engine oil will cause the engine to overheat is if it has oxidized and is now sludge or its extremely low.

What else can cause overheating?

As we’ve already covered, the likelihood that driving low on oil is causing the engine to overheat is very slim. However, many other components in the engine bay will cause overheating and other indicators. For one, the car may display the engine management light or go into limp mode when overheating. The other parts in an engine bay that can cause overheating are:

How to check if low oil is causing a problem?

Checking whether low oil is causing an issue is precisely as you would think, top up the oil level and get back in the car for another drive. If the fault remains, either driving low on oil has caused permanent damage or there is another fault. It would be wise to take your car to a mechanic to inspect it as soon as possible. Some of the faults, like the ones above, are cheap fixes; ignoring them could result in a more costly fix later.

Frequently asked questions

Can low oil cause overheating while idling?

The engine will overheat if low on oil when idling; it takes a while for the engine temperature to get to a point where it is a problem, though. If the overheating appears immediately after starting the engine unless there is virtually no oil, it will likely not be oil but another issue.

Can adding oil fix overheating?

If the car is low on oil and overheating, topping up the oil level is the first thing to do. If oil were the problem, it would sort out the overheating issue. There may be further problems if the engine damage is already apparent.

Can an overdue oil change cause overheating?

The oil needs changing because the qualities in the oil deteriorate and no longer provide adequate lubrication(cooling) alongside other benefits. If the oil level is still correct, being overdue for an oil change will not cause overheating.

Can I still drive my car if it’s overheating due to low oil levels?

It’s generally unsafe to continue driving your car if it’s overheating due to low oil levels. Low oil can cause the engine to overheat and potentially cause severe damage to your vehicle, including engine failure. It’s best to immediately pull over, turn off your car, check, and refill the oil before continuing.

Summary on can low oil cause overheating

To summarise, driving low on engine oil can cause overheating, but the blame may be a fault with another part of the engine. Check the level to determine how low the oil is before you consider driving; if the oil level is dangerously low, don’t do it; you will regret it, especially if you end up on the back of a tow truck. Instead, top up the oil level and see if the overheating disappears; you can be sure it was the oil level causing the issue.

My name is Tom although my friends call me Tommy. Messing around with cars and bikes has always been a hobby of mine even from a young age. So I made it my day job 17 years ago. I am a fully qualified mechanic as you would expect. I've worked in all different areas of the motor trade, valeting, panel beating, engine repairs, I'm sure you get the idea. I enjoy sharing my wealth of knowledge and experience with others, which is the reason I spend a lot of time here writing for this website.

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