10 Best Radiator Caps 2021 – Trusted Reviews & Guide

You might undermine the value of the radiator cap, and you might think it is not a very important vehicle component. After all, it is just a cap that is covering the radiator opening. Well, let us break this myth. The radiator cap is one of the most critical components of the car’s cooling system. It helps the radiator in functioning correctly. The lid has multiple seals, and these seals help the radiator in ensuring that the pressure can buildup for the circulation of the coolant. A faulty cap can lead to overheating of the cap as it will reduce the pressure, and hence it will reduce the boiling point of the water.

After years of use, the cap may become faulty as the seals can break-off. If you are having trouble with the radiator and if you notice any leaks from the cap, it is best to replace the radiator cap with the new one. There are many different options available, and some of them are better than the OEM caps in the market. In this article, we have listed some of the best radiator caps available in the market so that you can easily purchase one. So, let us move on to the next section and check out what we have on the list.

Best Buy Radiator Caps Reviews

If you do not have a lot of time to research about the radiator caps, then you can rely on the list that we have shared below. You can quickly go through the reviews along with the pros & cons to get an idea of the product. Click on the link associated with the listing, and you will be able to order the radiator cap. The whole process would not take more than 2 to 4 minutes. So, check out the best available radiator cap in 2021.

1. Stant Safety Radiator Cap

Stant Safety Radiator Cap

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One of the best brands for buying the radiator caps is Stant. You can buy any radiator caps from the brand and be assured that it will perform well. If you are looking for radiator caps with a safety lever, then you must buy this model. This cap has a thick gasket, and it fits well on the radiator. The cap is designed as per the specifications from OEM. The radiator cap prevents the over-pressurization of the radiator, which can lead to radiator punctures.

The pressure rating of this radiator caps is 16 psi, and it has a solid metal build. You can buy this radiator caps without a second thought, and we assure you that it will be better than the stock radiator caps that you received with your vehicle. You can use the product link above and check the compatibility of this radiator caps in your car.


  • Stant is one of the most reliable brands when it comes to radiator caps.
  • This radiator caps have a safety release to help you in releasing the pressure.
  • It has a pressure rating of 16 PSI.


  • Nothing that we could notice.

=> Check This Also: 10 Best Car Radiator Stop Leaks

2. Stant 10231 Radiator Cap

Stant 10231 Radiator Cap

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If you are not looking for radiator caps with the safety lever, you can check out this alternative option from Stant. This product is a perfect replacement for the faulty radiator caps. It features a SWIV-El design that makes removing and installing the cap much easier. Stant takes care to implement the exact OEM specifications while manufacturing the radiator caps. The cap has a metal construction, and it is designed with the best possible material. It doesn’t obstruct the design of the open cooling system, and it helps in an unrestricted flow of coolant to the reservoir.

It is one of the most reliable radiator caps that you can buy for your car. The brand has an excellent reputation, and the vented radiator caps perform better than your expectations. You will not notice any flaws or issues even after the long term usage of the radiator caps.


  • It has a sturdy metal construction that holds well under 16 PSI of pressure.
  • The radiator cap has a SWIV-EL design that makes it easier for you to install the cap.
  • These radiator caps are compatible with a wide range of vehicles, including trucks& SUVs.


  • Nothing about this radiator caps.

3. ACDelco RC27 Professional Radiator Cap

ACDelco RC27 Professional Radiator Cap

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ACDelco is another reliable brand available in the market when it comes to spare parts of the car. If you are looking for a premium radiator caps, then go ahead and consider this radiator caps from ACDelco. It is best suited for GM vehicles, and it seals the radiator perfectly. This radiator cap ensures the correct buildup of the pressure and improves the radiator’s efficiency.

The radiator cap offers the right kind of performance, and it is highly dependable as well. Because of the high-quality material, there is never a leak or an issue with the radiator caps.Overall, this radiator caps is quite a reliable option, and you can buy this without a second thought. It will help you in enhancing the performance of the radiator, and at the same time, it will also help you in ensuring that the radiator holds the pressure pretty well.


  • This radiator cap is compatible with all the vehicles, but it is best suited for GM vehicles.
  • The radiator cap is made of premium quality material.
  • The pressure rating of this radiator caps is 15 PSI.


  • Nothing as such.

4. Motorcraft RS-527 Radiator Pressure Cap

Motorcraft RS-527 Radiator Pressure Cap

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Some of the car radiators need a cap that can be screwed on the radiator tank. Such radiators have a different construction altogether. It is mostly applicable to the Ford vehicles. In such a case, the radiator caps listed above are not compatible with your vehicle. The answer to your problem is buying this radiator cap. It has a screw-type design that fits perfectly on such radiators. This listing is an OEM radiator caps from Ford. It can also fit other vehicles, and you will not face compatibility issues.

This radiator cap is available at an affordable price, and it cranks up appropriately with the engine. You will be delighted with the quality of the radiator caps, and you would not have to change the cap for many years. Ensure the compatibility of this radiator caps before buying it.


  • This radiator cap is perfect for the Ford vehicles with older radiator design.
  • It has an exact OEM specification, so you will not face any issues with the size.
  • Works well under high pressure, and the quality is excellent. The pressure rating is 16 PSI.


  • It has a screw design, so check for compatibility with your vehicle.

5. Stant Radiator Cap

Stant Radiator Cap

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Here is the third product from Stant, and it is again one of the most reliable options in the market. It is a standard metal radiator cap that fits most of the vehicles. It has easy to use a design that makes it easy to install the radiator cap. The radiator cap clicks after the radiator cap is installed correctly. The top section of the radiator cap’s diameter is 2.6 inches, and the height of the radiator cap is 1.06 inches. The spring system helps in retaining the pressure.

The radiator cap can hold the pressure between 14 pounds to 18 pounds. If you have a faulty radiator cap, then do not buy the ones at the dealership. This radiator cap is available at a fraction of cost when you compare the price of the radiator cap available at the dealerships.


  • Stant has commendable goodwill in the market, and this assures you of the quality of the radiator cap.
  • It is available at an affordable price, and hence it is a justified replacement.
  • The radiator cap is compatible with a wide range of vehicles.


  • Nothing that we could notice about this cap.



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At number 6, we have a radiator capo from MotoRad. The brand is famous for spares, and this radiator cap is a premium product that you can buy. It meets all types of specifications for the OEM products, and it ensures a proper vacuum in the radiator assembly. The brand tests the cap extensively, and it can take a lot of abuse as well. You can install the cap easily as the shell of the cap is independent of the gasket.

These caps are tested for longevity, so if you are looking for a durable cap, this is the right product for you. Overall, the cap is reliable, and you can buy this if you are looking for a standard fit radiator cap for your vehicle.


  • This radiator cap can take a lot of abuse, and it is one of the premium options available in the market.
  • The pressure conditions are optimal, and the quality is excellent.
  • It is available at an affordable price.


  • The brand has not listed the pressure rating on the website.

7. Motorcraft RS76 Radiator Cap

Motorcraft RS76 Radiator Cap

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Here is the second option available from Motorcraft on our list. You would have noticed that some radiator caps can develop a certain level of rust on them. Rusting is mainly because the coolant can be corrosive. If you are changing the old radiator cap because of the corrosion, you might want to look at this option. This radiator cap is highly resistant to oxidation. It has a long service life, and it can resist high levels of pressure as well as temperature.

Motorcraft is known for selling the OEM parts for Ford. This cap is a perfect option if you have a Ford Truck and are looking for a radiator cap compatible with Ford. Go ahead and check out this radiator cap, and we are sure that you are going to love it.


  • The pressure rating of this radiator cap is 16 lbs., and it can resist high temperatures.
  • The cap is resistant to rusting.
  • These radiator caps are a perfect fit for Ford vehicles.


  • Nothing as such.

8. ACDelco RC95 GM Original Equipment Radiator Cap

ACDelco RC95 GM Original Equipment Radiator Cap

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We have talked about radiator caps from ACDelco, and here is yet another option from the brand. The previous product from ACDelco had a standard fit design, whereas a lot of GM and Ford vehicles may need a screw-type radiator cap. If you are looking for such a cap, then you can consider this option from ACDelco. The cap helps you in maintaining the pressure, and it enables you to keep the vehicle cool. The perfect pressure ensures that the boiling point of water stays high. The pressure, in turn, reduces the expansion factor, and it nullifies the chances of radiator explosion or puncture.

The cap is durable, and it is as good as OEM parts for the GM vehicles. It is universally compatible, so do not worry about the compatibility. Just check the screw-on mechanism before making the purchase.


  • It is the best option for GM vehicles.
  • This radiator cap has a pressure rating of 15 PSI, and hence it is very durable.
  • ACDelco has a good market reputation so that you can rely on the radiator cap.


  • Nothing that we could notice

9. Gates 31336 Radiator Cap

Gates 31336 Radiator Cap

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If affordability is your concern, then you can also buy the radiator cap from Gates. It is a standard radiator cap that fits most of the vehicles. It has a pressure rating of 16 pounds, and it performs pretty well in all types of conditions. This radiator cap works as expected, and you will not face any issues with the cap. Note that the cap is manufactured in China, and many people may want to steer clear of such products over quality concerns.

As per the general opinion of the consumers, this radiator cap is affordable, and it works as expected. Before you buy, you can check the compatibility by visiting the product link listed above.


  • It is a standard radiator cap that is most compatible with all types of vehicles.
  • The pressure rating of this radiator cap is 16 pounds.
  • It is one of the most affordable option in the list.


  • It is made in China, and some people do not like the quality of the cap.



Buy From Amazon

We have reached the end of our list, and this radiator cap comes with the safety lever. Since this radiator cap is from MotoRad, you can rely on the quality of the cap. The safety level helps in the removal of any residue pressure before you open the cap. It ensures that the water doesn’t splatter around, and you are not injured because of it. The pressure rating is suitable for almost every car. Just like other spares, MotoRad tests this radiation cap for longevity.

The manufacturer has taken care of OEM specifications while manufacturing the cap. It is available at an affordable price, and you will not face any problem while changing the cap. It will help you in maintaining the right amount of pressure that enables a proper circulation. For any other information, you can visit the product link listed above.


  • This radiator cap has a safety lever that allows you to release the pressure when you are changing the cap.
  • The cap is easy to change, and it fits perfectly on most of the vehicles.
  • The quality of the cap is excellent.


  • Nothing that we could notice.

How To Choose The Best Radiator Cap

We have already shared the list of best radiator caps with you. You might still want to choose a different radiator caps for yourself. In such a case, it is better to educate yourself about the factors that can impact your radiator cap’s choice. These factors will help you in ensuring that you are buying the product that is the most reliable offering.

Go ahead and check out these points listed below.

  • Material of Body

You can start by looking at the material that the manufacturer uses for making the radiator caps. You will find some cheap quality products that use plastic. Our recommendation is to avoid those radiator caps. It will be better to purchase the radiator caps that use the metal. They will undoubtedly have rubber seals, but the overall construction and the top head of the radiator caps should be manufactured using sturdy metal.

  • Safety Lever

The next thing to look for is the safety lever. Well, this particular feature is a personal choice. The safety lever will help you in releasing any kind of pressure before you open the radiator caps. It is not a must have feature, but it is good to have feature. A safety lever can prevent any accidental injury when you are trying to open the radiator caps. After releasing the pressure, the chances of any spillage or spatter of the hot boiling water is reduced to nil. So, consider yourself changing the radiator caps and choose for yourself.

  • Pressure Rating

The next thing that you must check is the pressure rating that is supported by the radiator caps. The cap plays a significant role in maintaining the pressure of your radiator unit. They are all rated for up to a specific pressure. An excellent value is around 15 psi to 16 psi. You can also check the car manufacturer’s specification sheet to understand what kind of rating you need in terms of the pressure. Do not ignore this aspect of your purchase.

  • Brand

The next thing to consider here is the brand. You do not want to compromise on your safety, and you do not wish to encounter a blown-up cap during a long drive. To avoid all these situations, you must only buy a radiator cap from a reliable brand. Do not buy the cheap knock-off radiator caps as they can be damaging for the car.

  • Warranty

Some brands give a warranty on the radiator caps. You can choose the brands and the models that come with the warranty. Now, it is not completely necessary to buy the radiator caps with a warranty, but it certainly gives you a certain level of peace of mind. The guarantee assures that the radiator caps are reliable, and the brand is ready to take ownership of faulty caps.

  • Price

Pay attention to the price of the radiator caps and steer clear from any outlier in the market. The expensive ones may not be worth the price and the cheap ones may have inferior quality. The best bet is to choose something in the mid-range.

  • Size

Here is an extra point that you may need to consider. The fact is that most of the radiator caps are of standard size, but few older models were taller than today’s version of radiator caps. If you have an old car and have those taller radiator caps, ensure that you buy the compatible products.

Common Signs of a Faulty Radiator Cap

Radiator plays the most important role in keeping your car engine temperature low. Adding coolant to the radiator enhances the performance, provide better mileage and prevent the engine from other issues. If your car radiator isn’t working properly, you might face issues like the excessive temperature of the engine. In such cases, the radiator cap seems like the primary culprit. To understand it in easy words, there are few basic signs that you can notice to figure out radiator cap issues –

  1. Leakage in Coolant

The coolant reservoir helps in keeping your car temperature lower. When there is an issue with the radiator cap and it is stuck, it will build pressure inside the radiator. The worst part is, it will cause leakage in the hose. You can find dripping coolant under the car. Checking the coolant level in the reservoir is easy to understand if everything is fine or not.

  1. Notice Temperature gauge

Once your car is turned on and the radiator is not working fine, the temperature will rise quickly. The cooling system starts performing poorly and it can make you replace the coolant. But, even you replace or add a new coolant, the temperature gauge will still show high reading. The reason behind the increase in temperature is the inefficient working of the radiator.

  1. Overflowing reservoir

As you put coolant in the reservoir, you can find that there are ideal level markings by the manufacturer. When the cap is not working fine and causing pressure, the coolant will go back to the overflow tank. This thing happens so quickly that the coolant starts boiling up. Boiling in the coolant is a key sign of a bad radiator cap and replacing the cap in such a situation is the only option.

  1. Engine Starts Overheating

Except for the temperature gauge, you can find that the Air conditioner doesn’t work properly. The smell gets inside the AC and it will make you feel dizzy. There is a certain smell and the cooling system isn’t performing also. In such cases, engine temperature rises to unfamiliar levels. Waiting to cool down your car engine temperature is the only solution to travel a few miles.

  1. Radiator Hose Collapsing

With the intense pressure in the radiator, the primary issue that you face is with the radiator hose collapsing. When the hose collapse, the efficiency in cooldown decreases by half. Your AC isn’t going to perform properly, the car engine heats immediately, noisy engine and more. In these situations, coolant is necessary.

Note – In the new cars, most manufacturers started introducing high-pressure radiator caps to eliminate pressure build inside the radiator. These caps have a special valve to get rid of excessive pressure and preserving the coolant from contaminating at the same time. 

Radiator Caps Frequently Asked Questions

  1. I am planning on purchasing a radiator cap, how long could I expect one to last?

On average, a radiator cap could last about 10-years. This lifespan could increase or decrease based on the frequency of use. If the frequency radiator use is high, the lifespan could decrease, on the other hand, if it is not high, then lifespan could increase above 10-years.

  1. Blowing away head gasket and radiator cap could be a result of a faulty radiator?

A head gasket failure could be a result of a faulty radiator or it may be due to frequent heating of the engine. Clogged radiator, faulty radiator fan, leaking coolant, etc., are some of the key reasons that could lead to a head gasket and radiator cap failure. A blown head gasket and radiator cap could lead to engine failure as with a radiator function properly, it would lead to engine overheating, which, eventually leads to engine failure.

  1. Apart from blown away radiator cap, when is the right time to replace a radiator cap?

A radiator cap blowing away is not a sudden issue, for the radiator to blow away, it could take some time. If you watch the radiator cap closely, you could avoid such an issue. The first thing you should do is check if there is rust inside the radiator cap. Check it frequently and if you doubt that it might blow off, then replace it. You must remember that radiator caps are cheap and replacing it might not be a difficult thing. Consider doing it, if the situation demands it.

  1. Is it possible to drive a car without a radiator cap?

Yes, you could keep on using the car without a radiator cap, but, you will have to fill the radiator coolant every time before using the car. A radiator without coolant is just a fan, if there is no coolant, then the engine would overheat. The overheated engine could breakdown at any time. No matter the car manufacturer, overheating of engine and engine failure cannot be avoided and no car manufacturer would recommend or support such an action.

  1. The radiator cap is a very small part when compared to the radiator and engine, why is it important, my mechanic asked me to replace the cap soon, shall I neglect the recommendation?

The radiator cap is often overlooked by most customers. They assume such a small part to be worthless. If you are such a person then listen to this. A radiator cap is as important as the radiator and the coolant fluid in it. A faulty radiator cap would allow the coolant to leak and the loss of coolant fluid would reduce the efficiency of a radiator. The inefficiency of a radiator would lead to the engine overheating and engine overheating could eventually lead to engine failure. The radiator cap helps to keep the cooling system pressurized, which, in turn, increases the efficiency of the cooling system (radiator). Without an efficient radiator cap that prevents leaks and locks the pressure, a car could breakdown at any time.


We have shared all the possible information about the radiator caps with you. This article covers everything, including the buying guide for the radiator caps. If you have any issues with the cap of the cooling system, you can address it by changing the radiator caps. While changing the radiator caps, ensure that the engine is not hot, and there is no pressure buildup in the radiator. The best approach is to change the radiator cap in the morning even before you fire up your engine.Replacing the cap in the morning will ensure that coolant is at the outside temperature and there will be no chance of an injury.

So, we are now going to conclude this review about radiator caps. If you have any feedback or any questions, you can reach out to us via the comment section. Thank You.