# Does coolant mix itself in the engine **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [July 4, 2017, 5:35am UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579 "2017-07-04T05:35:19Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![TheMidnightNarwhal](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/themidnightnarwhal/32/5375_2.png) [@TheMidnightNarwhal](https://community.cartalk.com/u/TheMidnightNarwhal)\ **Post date:** [July 4, 2017, 5:35am UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/1 "2017-07-04T05:35:19Z")
Ok so this a very basic and noob question but do I need to mix coolant (if bought concentrated) before out of the engine or can put 50% coolant into rad then put the other 50% of distilled water and it’l mix itself or is that bad? ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [July 4, 2017, 5:46am UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/2 "2017-07-04T05:46:11Z")
We have had a few discussions on this, I ended up thinking the 50/50 mix was logical due to doing a flush with the hose adapter one only got 1.5 gallons of the three by draining the radiator, so yes it will mix, but the hose job was not using distilled water, as seems to be the preference these days. ---
**Author:** ![Waterbuff](https://avatars.discourse-cdn.com/v4/letter/w/f07891/32.png) [@Waterbuff](https://community.cartalk.com/u/Waterbuff)\ **Post date:** [July 4, 2017, 5:47am UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/3 "2017-07-04T05:47:51Z")
Plenty of people only add diluted to make things simple. OTOH, concentrated coolant and distilled water will mix inside the cooling system. If you need to feel better about it, alternate additions of smaller amounts of each. Like one quart undiluted coolant, then one quart water, then repeat. You help the mixing go faster this way. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [July 4, 2017, 12:29pm UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/4 "2017-07-04T12:29:23Z")
You can mix it in the engine. Pour the coolant in first. The "surprise " that happens is if you drain 1.5 gallons and pour in 3/4 gallon of coolant, no can’t get another 3/4 gallon of water in. You will eventually as the air burps out but better to have an over-percentage of coolant than the other way round. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [July 4, 2017, 2:20pm UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/5 "2017-07-04T14:20:29Z")
You can let the cooling system mix it. However, be sure you have the “concentrated” coolant rather than the “premixed” type, and use only distilled water (about $1 at any grocery store) to mix it with. Tapwater often contains stuff that while safe to drink may cause problems in your cooling system. That white mineral crust you see in the cleaning-chemical commercials is common and can really screw up a cooling system. The “premixed” stuff is already diluted for you. You need only pour it in and burp the system. ---
**Author:** ![TheMidnightNarwhal](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/themidnightnarwhal/32/5375_2.png) [@TheMidnightNarwhal](https://community.cartalk.com/u/TheMidnightNarwhal)\ **Post date:** [July 4, 2017, 5:48pm UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/6 "2017-07-04T17:48:05Z")
I never was able to find distilled water. Though at the local canadian tire they sell deionized which is made for rads. ---
**Author:** ![TheMidnightNarwhal](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/themidnightnarwhal/32/5375_2.png) [@TheMidnightNarwhal](https://community.cartalk.com/u/TheMidnightNarwhal)\ **Post date:** [July 4, 2017, 5:48pm UTC](https://community.cartalk.com/t/does-coolant-mix-itself-in-the-engine/105579/7 "2017-07-04T17:48:23Z")
Thanks for the replies guys!