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BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.Read more 
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Why trust BestReviews?
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and we never accept free products from manufacturers. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.Read more 
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We purchase every product we review with our own funds — we never accept anything from product manufacturers.

19 Models Considered
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120 Consumers Consulted
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We purchase every product we review with our own funds — we never accept anything from product manufacturers.

Buying guide for best radiator pump pressure tester kits

Last Updated November 2019

The cooling system is one of the most important components of a functioning engine. There’s many aspects of car maintenance that are up to debate and opinion. The one thing everyone agrees on, however, is the need to keep your engine from overheating: an overheating engine is an engine that won’t be running very long.

Unfortunately, many radiator and cooling system issues go undiagnosed or misdiagnosed, risking catastrophic failure and costly repairs. A radiator pump pressure tester kit can help you find and diagnose leaks in your cooling system and avoid problems down the road.

A pressure test kit allows you to safely duplicate the level of pressure the coolant system experiences when the engine is running, making it easier to look for leaks.

Engine coolant is made from a 50/50 mixture of antifreeze and distilled water.

How it works

To understand what to look for in a tester kit, it’s important to understand how your automobile’s cooling system works.

As coolant makes its way through your engine, it absorbs heat the engine generates. The radiator acts as a heat exchanger, cooling the coolant as air flows over it before the coolant goes back through the engine to absorb more heat. The coolant system is pressurized, which raises the boiling point of the coolant. This allows your engine to run at the temperature it needs to in order to operate efficiently, without boiling the coolant.

Key considerations

When buying a tester kit, one of the first questions you need to consider is whether you will be buying the kit for a single vehicle, or whether you plan on using it on several different makes and models. Some kits are geared toward specific makes, while others include adapters for almost every major car brand on the market.

Another factor to bear in mind is ease-of-use, especially if you’re not a professional mechanic. Some of the manufacturers go above and beyond to make their kits as easy and accessible as possible. For example, some models include color coded radiator test caps, with each color corresponding to an automotive brand. Since many of them look virtually identical at first glance, this is an easy way to make sure you’re using the right one for the right vehicle.

DID YOU KNOW?

Most engines run at 180 to 205 degrees. While water boils at 212 degrees, coolant boils at approximately 223 degrees.

Features

With a variety of options and price points, there’s a number of features you should look for when shopping for a tester kit.

Pressure rating

Kits come with different pressure ratings. Your typical cooling system is under 10 to 20 psi of pressure. There are aftermarket radiator caps that increase that pressure even higher, although the added pressure may cause additional stress on other components that weren’t designed to handle the pressure, such as gaskets, hoses and clamps.

Buy a testing kit that is rated for at least the same pressure as that listed on your radiator cap.

Refill tool

Some tester kits come with a refill tool designed to help you replace lost coolant without trapping air bubbles in the coolant system. Kits that include this feature are a good value, as a separate radiator refill kit can cost $60 to $70 alone.

Quick-snap connectors

Some tester kits come with a refill tool designed to help you replace lost coolant without trapping air bubbles in the coolant system. Kits that include this feature are a good value, as a separate radiator refill kit can cost $60 to $70 alone.

High-capacity pump

Self-locking, quick-snap connectors are another convenient feature included with many tester kits. This not only makes it easy to connect and disconnect the kit’s components, but also ensures you don’t accidentally lose pressure from a poor connection.

When a coolant system is under 15 psi of pressure, the boiling point of the coolant is raised to approximately 260 degrees. This provides the engine enough buffer to be able to run under a variety of conditions without the coolant boiling and the engine overheating.

Staff
BestReviews

Price

Tester kits can vary quite a bit in quality and price. This is definitely a product category where you get what you pay for.

Inexpensive: The cheapest kits will include support for a few makes or will focus on regional manufacturers. For example, they may work with US and Asian manufactured cars, but not European. The radiator caps are often not customized for a particular make, but a type of generic, one-size-fits-most style. These kits will cost $35 to $75.

Mid-range: Mid-range kits will include wider support for a range of autos, custom radiator caps and improved materials and construction. These kits will run $75 to $125.

Expensive: These kits are a substantial improvement in quality. They will usually work with almost every make of automobile, are crafted from high-grade materials and will often have purge and refill systems included. Expect to pay $125 to $250.

Tips

  • Never open your radiator cap when your engine is running, or has been running recently and is still hot. Allow plenty of time for the engine to cool. Remember, your coolant system is under pressure and contains liquid that is near boiling temperature. If you open the radiator while the engine is hot, that liquid can spray out and cause burns.

  • To see if the cooling system is currently under pressure, squeeze the upper radiator hose. The harder it is to squeeze the hose, the more pressure the system is under. Wait till there is little to no pressure before opening the radiator cap.

  • Make sure the cooling system is full before testing. The fluid in the radiator should come to just below the cap, and the overflow reservoir will have a line indicating maximum fill.

  • Never exceed the psi listed on the radiator cap. If you do, you risk damaging internal seals, gaskets and hoses that were not designed to handle the additional pressure.

  • Once you have the appropriate pressure, visually inspect the engine for any leaks or dripping coolant. Keep in mind that not all hoses are visible. Some are tucked away in the cabin. Even if you can’t see all the hoses, you should be able to smell the coolant if there’s a leak.

  • Keep an eye on your pressure gauge. If there’s no visible leaks, but your pressure drops more than a couple of notches within a few minutes, you could have an internal leak. This could be a sign of a blown head gasket.

  • Once your done testing, you need to release the pressure before taking the cap off. Some kits, especially the high-end ones, include a pressure release value. If yours doesn’t — and as long as the engine is still cold — slowly turn the cap and gently rock it back and forth to safely release the pressure.

  • If everything checks out, with no indication of leaks, but you’re still losing coolant when driving, you probably have a bad radiator cap. Some kits include an adapter to test the cap, while others don’t. Most radiator caps are inexpensive so, when in doubt, buy a new one.

Other products we considered

The Toolsempire 28-Piece Set Universal Radiator Pressure Tester is a good middle-of-the-road option. It includes color coded caps, support for virtually every make, as well as a vacuum purge and refill tool.

The Astro 7858 Universal Radiator Pressure Tester is a relatively high-end kit that includes a 35 psi gauge for testing higher pressure systems, color coded caps, anodized aluminum adapters and works with most makes.

Some extreme scenarios, such as car racing, may require a specialized coolant mix that can handle higher temperatures.

FAQ

Q. I do some mechanic work on the side. Will any of these kits hold up to professional use?
A.
Absolutely. Many of the more expensive kits are used in shops across the country and should hold up well with proper care.

Q. If a kit doesn’t have an adapter for my vehicle, can I order it?
A.
On high-end kits, yes. Manufacturers ship the kits with the most common adapters to keep the price low. If you need additional, less common adapters, you can order them and the kit’s case probably has open slots to put them in.

Q. Is there any other way to know if my radiator cap is bad?
A.
If you can’t find any leaks, but the vehicle overheats when the engine is running, you can try running the engine with the pressure tester connected in place of the radiator cap. If the vehicle doesn’t overheat then it’s almost certainly a bad radiator cap that’s no longer keeping the system pressurized and allowing the coolant to boil.

The team that worked on this review
  • Jacob
    Jacob
    Editorial Manager
  • Katie
    Katie
    Editorial Director
  • Melinda
    Melinda
    Web Producer

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