# Coolant, materials and warranty

Lesson 3 of [Evaluate a liquid cooling vendor before you buy](https://liquidcooling.fyi/academy/evaluate-a-liquid-cooling-vendor.md), 13 minutes.

The coolant touches every part of the IT loop. A wrong choice can cause leaks, blockage or a lost warranty. Ask about the coolant - Which fluid does the vendor supply for the IT loop? - Did the server maker qualify that fluid for the warranty of the servers? - What is the replacement interval, and h…

The rest of this lesson is for learners enrolled in the course. [See how Evaluate a liquid cooling vendor before you buy works](https://liquidcooling.fyi/academy/evaluate-a-liquid-cooling-vendor.md).

Also on the [web page](https://liquidcooling.fyi/academy/evaluate-a-liquid-cooling-vendor/coolant-materials-and-warranty).