Best Antifreeze Tester in 2027

The TRZ RHA-100ATC is a refractometer that reads freeze protection for both ethylene and propylene glycol. Its ethylene scale runs from -84 to 32 °F. The propylene scale runs from -60 to 32 °F. That range suits cold climates, and it also shows glycol concentration, which helps you judge whether a mix is too weak. Percent readings reach 70% for ethylene and 63% for propylene.

Beyond coolant, the listing says it reads battery specific gravity from 1.100 to 1.400 sg and DEF urea concentration at 30% to 35%. That makes it a shop tool for more than one fluid. It weighs 0.31 lb, the lightest of the four models that list a weight. That is easy to carry in a tool bag. Those extras matter if you also service batteries and diesel trucks.

The spec data does not confirm automatic temperature compensation, even though the model name includes ATC. It also lists no case. Read the listing before you buy if either matters to you. Treat that as a gap to check, not a defect.

The Tiaoyeer bdzsy143 ranks second on our list. It is a refractometer for ethylene and propylene glycol coolant. The ethylene scale spans -84 to 32 °F and the propylene scale spans -60 to 32 °F. Those numbers are the same as the top-ranked model, so freeze-point coverage is not what separates them. The listing calls the unit compact and light, though it gives no weight.

It lists automatic temperature compensation. That matters because coolant readings drift when the sample and the tool are at different temperatures. The listing adds 0-70% glycol concentration for ethylene and 0-63% for propylene, plus battery specific gravity from 1.100 to 1.400. Specific gravity shows battery charge condition. Percent readings help you check that a mix is not too lean. The listing describes three functions in total.

It does not list DEF or washer fluid testing, a carry case or a weight. If you need those, look elsewhere in the table. For plain coolant and battery work, the feature set is complete. That narrower scope is a fair trade for many home garages.

The aichose SR0022-ATC ranks third. It is a four-function refractometer. Its glycol scale covers -58 to 32 °F for both ethylene and propylene, so one range serves both types. That is a narrower low end than the models that reach -84 °F on ethylene or -60 °F on propylene. Freeze readings for coolant are the core job here, and it handles them.

Where it stands out is range of fluids. The listing adds windshield washer fluid from -40 to 0 ℃ for ethanol or isopropyl alcohol types, DEF urea at 30% to 35%, and battery acid specific gravity from 1.10 to 1.40 kg/l. It also lists automatic temperature compensation.

The data does not show a glycol concentration percent scale, a carry case or a weight. If you want to read the percent of glycol in the mix, pick a model that lists it. For a shop that also handles diesel and washer fluid, this fits. Check the listing for the scale layout before you buy.

The WATETTY001 ranks fourth and lists three functions: freeze point, glycol concentration and battery acid specific gravity. Freeze readings run from -84 to 32 °F on the ethylene scale and -60 to 32 °F on the propylene scale. Those figures match the top two models, so coverage for common coolants is strong. Those numbers tell you how far freeze protection extends for each glycol type.

It has automatic temperature compensation. The listing says you put two or three drops on the prism, then hold it to the light and read the scale through the eyepiece. No battery is needed because the lens is optical. Concentration runs 0-70% for ethylene and 0-63% for propylene. Percent readings help you confirm the coolant mix ratio.

The listing gives no weight, no DEF or washer fluid test and no case. It is a plain tool for coolant and batteries. If you need more fluids, other models in the table cover them. Check the listing for fit with your fluids before you order.

The Hallocool HC00019 ranks fifth. It is a three-function refractometer for ethylene and propylene coolant. The ethylene scale runs from -84 to 32 °F and the propylene scale from -60 to 32 °F. It also shows glycol concentration, up to 70% for ethylene and 63% for propylene. Those figures tell you how cold the mix can get before it freezes.

Build is its distinct point. The listing describes an aluminum body with an ABS rubber grip, described as anti-rust and wear-resistant. That suits a garage where tools get dropped and handled with oily hands. Automatic temperature compensation is listed, which helps keep readings steady as ambient temperature changes.

It also reads battery acid specific gravity from 1.10 to 1.40 kg/l. The data lists no DEF or washer fluid test, no case and no weight. Without a case, you will want to store it in a safe spot between uses. If you need those, look at the models with more functions.