Why are antifreeze testers useful? Made up of a combination of antifreeze and water (often in a 50:50 split), coolant is integral to the smooth running of an engine. In the colder months of the year, having a tester in your line up of winter products is more important than you might think.
In winter, the antifreeze lowers the freezing temperature of the water, while in summer, it raises the boiling point to prevent overheating. In short, it keeps your engine working in a goldilocks temperature zone – so long as you make sure you maintain it with the best tools for the job.
If you don’t check your coolant from time to time it can start to cause all manner of issues for your engine, all of which can cost you some serious cash if you’re not careful. If your coolant freezes, it can cause serious internal damage, while an overheating engine can mean the end for seals, head gaskets and even cylinder heads. Things go deep into your engine that not even a fancy torch can illuminate them.
The best antifreeze testers at a glance:
The best antifreeze tester: Draper Tools Disc Type Antifreeze Tester – Buy from Amazon.
Editor’s pick: Selay AK4122 Antifreeze Tester – Buy from Amazon.
Most high-tech antifreeze tester: Sealey VS0052 Refractometer – Buy from Amazon.
Affordable antifreeze testers can stop bad coolant before it becomes serious. One of these tools will spot if your antifreeze isn’t up to scratch, allowing you to change it before it does any damage to your engine. All testers we’ve chosen are easy to use, reliable and inexpensive, perfect for keeping in your toolbox. And if you need to stop your windscreen from freezing too, check out our guide on the best de-icer.
The best antifreeze testers
The best antifreeze tester
It measures from -7 to -37 °C and being built by Draper, is a durable item designed to last a good while, and of course, many antifreeze tests.
Pros
- Great quality tester
- Easy to use
Cons
- Other options are slightly more advanced
Editor's pick
Place the tube into the coolant chamber, squeeze the pipette to pull some coolant into the chamber and watch for how many discs inside float upwards.
Pros
- Easy to use
- Good value
Cons
- Some may find it a bit fiddly
Best quality antifreeze tester
Pros
- Great quality item
- Easy to read
Cons
- Must be careful when using
Best budget antifreeze tester
Pros
- An affordable option
- Easy to use
Cons
- Gauge might be hard to read for some
Best mid-range antifreeze tester
It comes in a plastic body which, while it isn't as well-built as the Draper unit, should last you a decent amount of time.
Pros
- Easy to use
- Trusted brand
Cons
- Build quality not as great as Draper's unit
Most high-tech antifreeze tester
You get a pipette, a storage case, and a tiny screwdriver. The Refractometer is quite high tech as it measures the refractive index of light passing through the sample mixture. It's an accurate method of testing your antifreeze, but one that requires a lot more expenditure than the other options on this list.
Pros
- Very accurate bit of tech
- Can be used to test screenwash, Adblue, and battery fluids as well
- Comes in handy storage case
Cons
- Doesn't represent as good value as the others
Best value refractometer
Unlike the Sealey however, it's not stated whether this device can test out Adblue. But it still remains a very accurate and professional method of testing our your antifreeze/coolant.
Pros
- Highly accurate method of antifreeze testing
- Comes with useful extras, including calibration screwdriver and fluid
- Good build quality and materials
Cons
- Isn't stated whether it can test Adblue
FAQs about antifreeze testers
How does an antifreeze tester work?
They’re simple and very affordable little devices, but they can potentially prevent a very large amount of engine damage from insufficient coolant running within.
An antifreeze tester takes an extract of the coolant from your radiator and indicates whether there is any dirt of if it’s full of particles that reduce the coolant’s effectiveness. If the coolant is showing these signs from your tester’s reading, it only makes sense to flush out the old coolant and refill it with new coolant.
How much antifreeze do I need for my car?
The definitive answer will be in your car owner’s manual as it differs between make, model, and engine. To check the level of your antifreeze/coolant, there should be markers for the minimum and maximum level, and if you need to top it up, ensure you’re using the correct one for your vehicle.
Where does antifreeze go?
There should be a reservoir under the bonnet with the cap labelling the product. It will either be spelled out as antifreeze or coolant, or it’ll be a symbol that indicates a thermometer in liquid. You will need to look out for the minimum and maximum markers and ensure your antifreeze is at the required level it should be.
Is antifreeze the same as coolant?
No, they’re slightly different. Antifreeze is a glycol-based liquid that’s concentrated and must be diluted with water before use. Only when the water is mixed with antifreeze is it referred to as a coolant.
If you’re wondering whether you can purchase pre-mixed coolant, you’ll be absolutely right. These are available too, but you must check if your vehicle and engine can take it.
What is OAT 33 and OAT 50 in antifreeze/coolant?
The difference lies in the concentration of Organic Acid Technology (coolant) when mixed with water. OAT 33 indicates that the concentration of coolant is at 33%, whereas OAT 50 means 50%.
OAT 50 is generally tailored towards heavy duty vehicles and will provide better coolant protection against freezing temperatures, and if you’re wondering what your vehicle uses, it’ll be listed in the manufacturer’s recommendations.
Other things to consider with antifreeze testers
Truth be told, what is there to talk about with them when their constructions are so utterly simple? The market is pretty much the same as the ice scrapers one, really. So, as a priority, you probably want them to accurately measure the temperature of your coolant. So the quality of the product’s construction will be key. There is a lot of cheap options out there from unheard-of brands. But we have you covered with testers from trusted tool manufacturers.
The next is your preferred method of reading. The disc-type testers are ultra-simple, but won’t be for everyone. The Unitec tester provides an actual dial which will suit a great deal of users. The bonus feature of that device is that if you apply it correctly, it shouldn’t leak. It can be fairly easy to have one or two drops or spillages with the disc types after testing. Talking of drips, you can make your windscreen free of them with a car-based glass squeegee.
The last thing is value. Although antifreeze testers are generally inexpensive products, how much you spend if always key. The top notch brands will always charge a little more. But you have to remember that the difference in price between the things isn’t that dear. A very different field to, say, a set of snow chains.
Aaron Hussain is a commercial content writer at Bauer Media writing for Parkers and CAR. He is obsessed with classic cars and anything with a fascinating story to tell.
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