If you want a long-lasting, factory-specified fluid for oil changes and complete system protection in North American vehicles, choose PEAK OET Purple Concentrate; if you need a durable, instant-reading tool to verify freeze protection levels during maintenance, choose KoiLykke Coolant Tester.
• PEAK OET Purple Concentrate: Offers up to 15 years or 350,000 miles of rust and corrosion protection using advanced OAT technology, but it is a chemical concentrate that requires mixing with water and cannot function without the vehicle's cooling system infrastructure.
• KoiLykke Coolant Tester: Provides instant visual readings of ethylene glycol freeze levels with six floating discs and an unbreakable plastic body, but it is merely a diagnostic instrument that measures fluid rather than replacing or treating it.
• Best for: PEAK OET is for anyone performing a full coolant flush or needing extended life protection for modern high-performance engines, while KoiLykke is for mechanics and DIYers who need to quickly diagnose existing fluid health before topping off or changing fluids.
This product is designed specifically for owners of modern, high-performance North American vehicles that require a purple organic acid technology (OAT) antifreeze. The core value here is longevity and protection. When installed as part of a complete flush and fill procedure, this concentrate guarantees service life protection of up to 350,000 miles or 15 years. That is a significant stretch compared to traditional coolants, meaning you are less likely to be dealing with overheating issues or corrosion buildup for over a decade.
The formulation relies on proprietary state-of-the-art organic acid technology. This isn't just generic green fluid; it is engineered to protect all cooling system components against rust and corrosion using the same inhibitor technology that protected your vehicle straight from the factory. This makes it the ideal choice for brands like Alfa Romeo, Chrysler, Dodge, Fiat, Jeep, and RAM. If your car came with purple coolant from the plant, this is the exact match you need to maintain that factory seal.
However, this product is a concentrate, not a ready-to-use solution. You must mix it with distilled water according to the recommended ratio before adding it to the system. It is not something you can simply pour into a radiator and expect immediate results without proper preparation. Furthermore, because it is a chemical additive meant for a specific type of engine cooling system, it is useless if you do not own a compatible vehicle or if you are looking for a tool to measure what is already inside. It is strictly for filling, flushing, or topping off systems that demand OAT chemistry.
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-11-07 · 6 min read · Independent comparison
If your primary concern is knowing exactly what condition your current coolant is in before you decide to change it, the KoiLykke Coolant Tester is the tool for the job. It features six large colored discs that float within the testing chamber to indicate the precise freeze protection level of ethylene glycol antifreeze. This visual feedback is critical for preventing winter damage. Instead of guessing if your mixture is too weak for a freezing night, you get an instant readout that matches the discs to a temperature chart.
The design prioritizes durability and ease of use in harsh environments. The body is constructed from virtually unbreakable plastic, which means it can survive drops in a garage or rough handling in a professional fleet setting. It includes a high-quality rubber bulb for drawing samples, allowing you to test fluid directly from the radiator or overflow tank. There is no need for batteries, complex calculations, or digital interfaces. You squeeze the bulb, observe the floating discs, and match them to the provided chart for immediate confirmation of your coolant status.
This tester is versatile enough for cars, trucks, buses, and even new energy vehicles. It is an essential companion for any mechanic or DIY enthusiast who maintains multiple vehicles or wants to ensure their fleet is winter-ready. However, it is important to understand what this tool does not do: it does not clean the system, it does not add protection, and it does not replace old fluid. It is purely a measurement device. If you need to perform an oil change or a full coolant replacement, you still need to buy the actual fluid after using this tester to confirm the old stuff needs to go.
• Best for extended lifespan: Choose PEAK OET Purple Concentrate if you want a fluid that lasts up to 15 years and 350,000 miles with superior corrosion inhibition.
• Best for diagnostic speed: Choose KoiLykke Coolant Tester if you need an instant, battery-free visual reading of freeze protection levels without waiting for lab results.
• Best for specific vehicle compatibility: Choose PEAK OET Purple Concentrate if you drive a North American brand like Chrysler, Dodge, Jeep, or RAM that specifies purple OAT coolant.
• Best for versatility across fleets: Choose KoiLykke Coolant Tester if you maintain a variety of vehicles including trucks, buses, and new energy vehicles that all require ethylene glycol testing.
• Best for active protection: Choose PEAK OET Purple Concentrate because it actively prevents rust and corrosion using factory-grade inhibitors, whereas the tester only monitors existing conditions.
• Best for physical durability: Choose KoiLykke Coolant Tester for its virtually unbreakable plastic construction, making it ideal for rough garage work where tools get dropped.
• Best for full system overhaul: Choose PEAK OET Purple Concentrate when you are performing a complete flush and fill to reset the cooling system's health.
• Best for routine checks: Choose KoiLykke Coolant Tester for quick pre-winter checks to ensure your current mixture hasn't lost its protective properties.
In my opinion, I would buy the PEAK OET Purple Concentrate for my own vehicle because I prioritize long-term engine health and the peace of mind that comes with a 15-year guarantee. The ability to prevent rust and corrosion with the same technology used at the factory is far more valuable than simply measuring the fluid. While the KoiLykke tester is a clever tool for diagnostics, it is secondary to having the right fluid in the first place. If I am doing an oil change or a major cooling system service, the priority is getting the correct, high-performance concentrate that protects the engine for decades.
No, this is a concentrate formula. You must mix it with distilled water before adding it to your vehicle's cooling system to achieve the proper protection levels.
No, the tester uses a mechanical system with floating discs and a rubber bulb, so it provides instant visual readings without any need for power sources or complex calculations.
Yes, the tester is designed for wide vehicle compatibility, including cars, trucks, buses, and new energy vehicles, specifically for testing ethylene glycol antifreeze levels.
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