Can You Drive Without A Radiator Cap? At one point in every driver’s life, you have probably opened the radiator cap when the engine is hot. What you saw was coolant and bubbles pouring out from the radiator.
Even though it’s not recommended to open the radiator cap when the engine is hot, most of us have done it, and we all know the consequences.
With that in mind, you are probably aware of what will happen when you drive without the radiator cap.
The radiator cap plays a critical role in stabilizing the coolant in your car’s engine. The high temperatures of the engine often cause bubbles to develop within the coolant system.
With the cap well fitted on the radiator, these bubbles are confined within the engine, and the coolant can move easily.
But when you take the radiator cap out of the equation, the bubbles will push the coolant out of the radiator neck in massive burps.
This will result in loss of coolant, which can lead to damage to the gasket resulting in leaks.
Running an engine without a radiator cap will mark the beginning of engine issues that won’t be easy to remedy. You need to ask yourself – are these costly repairs worth driving around without a radiator cap?
Can You Drive Without A Radiator Cap?
[toc]
What is the Radiator Cap, and Why Do You Need It?
Most car owners can easily point to the radiator cap in their engines. It also goes by the name pressure cap. When you look at its build, you may notice how simple it seems, and you may not associate it with being of much value to your car’s engine.
That’s why you may even contemplate operating your car without a radiator cap. But before you take this leap of risk, you should do some research about radiator caps.
Radiator caps often last for a very long time without requiring replacement. But, when it gets faulty or pops out of the neck, you may notice your engine overheating or losing a lot of water or coolant.
The radiator cap is an excellent pressure-releasing agent. Within the engine, the high water temperatures often lead to an increase in pressure. This pressure can sometimes be more than what the cooling system is designed to handle.
A radiator cap features a spring-loaded valve that releases coolant from the system into the overflow tank. This helps regulate the pressure in the system and prevents the components from exploding.
When you finally turn the car off and the engine cools, a vacuum is left behind, and the same radiator cap release coolant from the overflow tank to the cooling system.
As you can see, the radiator cap is a simple component. But it plays a critical role. So, don’t drive your car without the lid.
How Often Should You Check Your Radiator Cap?
Always! You should never knowingly drive your car without a radiator cap. Every morning before going to work or running errands, you need to pop the hood and inspect the state of all components.
If you are always used to seeing your radiator cap intact, you can easily overlook it. So, always check its condition. At times, the radiator cap may not fall off from the neck, but it can wear out because of the environment it is constantly being exposed to.
Will Driving Without Radiator Cap Cause Engine Overheating?
Unfortunately, without a radiator cap, your engine will overheat very fast. With no cap to prevent water bubbles from pouring outside the radiator neck, you will lose a lot of coolant.
Secondly, the pressure in the cooling system will be low, and this will also result in overheating of the engine. So, yes, when you drive without a radiator cap, the engine will overheat, which may lead to gasket damage and leakage. This is another costly issue.
Will the Engine Overheat If the Radiator Cap isn’t Correctly Tightened?
You can expect a similar outcome if you don’t tighten the radiator cap. If it’s not tightened, there is no difference from driving without the radiator lid fitted on the neck. That’s because coolant will pour out, and there will be nothing to relieve pressure.
How Much Coolant Can I Lose from Driving Without the Radiator Cap?
That depends on how efficient your engine is. In new cars whose engine systems have been formulated to regulate temperatures, you can lose about half the coolant after moving around without a cap for a few days. By a few days, we mean three to five days.
All the coolant should have come out through the radiator neck in a week.
If your car is in great shape, you should notice increased engine temperatures. That should beckon you to check the coolant levels and other causes of overheating.
In cars with high mileage, if you lose the radiator cap now, the temperature gauges will be off the roof within an hour or two of driving. Also, you may notice shifting issues, leaks, and other signs of radiator failure.
We hope you can see how dangerous not having a radiator cap is because most of these issues are severe and can cost you thousands of dollars in repairs.
How Can I Know My Radiator Cap Has Come Off?
If you open a radiator cap, you must ensure you close it correctly. This shouldn’t be so hard to do because you have to turn the cap in a clockwise direction till you can feel it firmly shut.
At times, if you put it on too loosely and drive on a bumpy road, the cap can fall off without you noticing. If you go for short rides, you may not realize your radiator cap has come off. But, if you drive for long distances, here are some signs you should be on the lookout for;
- Leakage of coolant
Since coolant is colored, you should be able to spot stains after you stop your car on a particular spot. It’s essential for drivers always to be aware of their surroundings and vehicles.
- Empty reservoir
When coolant is hot, and under high pressure, it can be sent to the reservoir tank. If you notice that this tank is abnormally empty, chances are there isn’t enough pressure.
- Overheating of the engine
The most obvious sign that you are don’t have a radiator cap is if the engine is overheating. You should see that warning on your dashboard.
The best way for you to know that your radiator cap has come off is by popping the hood and looking. Otherwise, you will have to rely on these signs/symptoms, which could also signal another problem.
Is It Possible to Drive a Car Without a Radiator Cap?
You can drive a car without a radiator cap provided you refill some coolant and water every 10 miles. Driving a vehicle with an open radiator neck will spill coolant and water throughout the entire drive.
Coolant is the main ingredient needed in the cooling system. Without coolant, there is no cooling, and that results in overheating. By now, you should have a rough idea of the dangers of overheating.
If you must drive without a radiator cap, have some excess coolant at your disposal and fill it in after every twenty or thirty minutes.
How Tight Should the Radiator Cap Be?
If the engine is hot, fitting the radiator cap can be challenging. So, you may not close it all the way around. In one short turn, you should be able to close the coolant cap tightly.
There aren’t different levels of tightness. Practice opening and closing the radiator cap frequently to get the hang of how it works.
How Long Does a Radiator Cap Last?
As mentioned earlier, very few people have issues with radiator caps. These caps are designed to last for a significantly long period. A radiator cap can last for up to ten years.
This is even longer than the period most people own the cars themselves. So, there is a possibility of you never running into such an issue.
But despite radiator caps lasting so long, as they relieve pressure from the radiator and get opened or closed frequently, they wear out.
A radiator cap can wear out within two to ten years. It’s best to replace them after three years. This prevents the risk of the lid falling off as you drive.
How Much is a Radiator Cap?
The cost of a radiator cap can’t even be compared to the money you will spend on a blown gasket or engine. A radiator cap costs around $5 to $50.
The price will depend on the make of your car. Replacement is often free, and it’s done where you have bought the new cap.
For a component that only costs $50, is it worth driving your car without it and paying hundreds of dollars for engine repairs?
If you lose your radiator cap or it becomes faulty, you shouldn’t drive your car without it. Head over to an auto store near you and get a radiator cap for your vehicle.
Considering how widely available radiator caps are and their price, every car should have one at all times. You don’t need any professional skills to replace a radiator cap.
Provided you find the right fit for your vehicle your engine and cooling system should operate perfectly.