Library · Preps

Preps & treatments

Coolant is not a cleaner. Every one of these exists so the fluid you fill with can do its actual job instead of scrubbing your loop. Two kits if you want the decision made for you, five bottles if you want to build the sequence yourself.

Start here

Which one do I need?

Brand-new parts, nothing has ever run through the loopComplete Prep Kit — New SystemRad Clean → SysPrep → PrimoPrep

Rebuilding a loop that has already run coolantComplete Prep Kit — Existing SystemRad Clean → System Reboot → PrimoPrep

New radiator, you already have plastic fill-port fittingsRad Clean — StandardOne bottle per radiator · plastic caps only

New radiator, you don't have plastic fill-port fittings yetRad Clean — Full KitConcentrate + plastic fittings + funnel, all in one

Switching from an opaque fluid to a clear oneSystem RebootLifts dye staining as well as residue

Annual service on a healthy loopRad Clean + SysPrepRadiators, then a full-loop pre-treat

Mixed-metal loop with a large copper radiatorPrimoPrepControls the copper-driven pH swing

Neglected loop, heavy residue, pre-treatment will not cut itSystem SoapThen re-prep from the top

In what order

The sequence, start to fill

01Rad CleanRadiators on their own, before assemblycirculate 1 h dwell

02SysPrepWhole loop — lifts manufacturing debriscirculate 12–24 h

03PrimoPrepWhole loop — settles the pH swing a copper radiator introducescirculate 72 h

Refilling a loop that has already run coolant? System Reboot takes SysPrep's place in the middle — same 15 ml to a gallon, circulated 24–48 hours. PrimoPrep still follows it either way.

A multipurpose cleaning and maintenance tool rather than a single-job treatment. Mixed with warm water it preps components before installation. It lubricates silicone bending cord so an insert comes back out of a fresh bend cleanly. Circulated through a heated loop it works as a gentle cleaner for coolant residue. And it works as hand soap after a building session.

Component prepA few drops in warm water

In-loop cleaningAdd sparingly to a heated, circulating loop

BendingLubricates silicone insert cord for hardline work

CautionMix conservatively in-loop — excess creates foam. Not aluminium safe.

Buy on PrimoChill.com$4.99

Do not use with

Aluminium components, anywhere in the line. Rad Clean additionally needs plastic fill-port caps — it is not safe against nickel plating during the dwell.

Where it sits in the sequence

Used as needed — component prep, bending-cord lubricant, or a light in-loop clean. It isn't tied to one specific step.

Inside the loop

Three things are trying to ruin your coolant right now

This is what every bottle above is defending against. The mechanism, the visible symptom, and the product that stops it.

Galvanic corrosion at every metal junction

Put copper and nickel in the same wet circuit and you have a battery. Electrons move from the less noble metal to the more noble one, and the nickel plating on your block starts to lift in flakes you will find in the reservoir six weeks later. Temperature accelerates it: a loop that idles at 45 °C corrodes faster than one that never leaves 30 °C.

Onset

Weeks to months

Reversible

Partly

Product

Liquid Utopia

The fix

Liquid Utopia carries a corrosion inhibitor package that plates a molecular barrier onto exposed metal. 15 ml per gallon of DI or distilled — under-dosing is worse than not dosing, because a partial film leaves anodic hot spots.

Why any of this

A coolant used as a cleaner is a coolant that clouds.

Every block, radiator and fitting arrives with something on it — machining oil, casting flux, cutting debris. If the first thing to meet that residue is your coolant, the coolant spends its inhibitor package cleaning instead of protecting, and you see the result as a film at week three.

Prepping is ninety minutes. Not prepping is a teardown, and it is almost always blamed on the fluid.

Changing coolants? Do this.

01Drain completely, from the lowest point

02Rad Clean through every radiator

03System Reboot if the old fluid was opaque

04Distilled rinses until runoff is clean

05SysPrep, then fill with the new coolant

Keeping It Cool is the technical library of PrimoChill. Products ship from primochill.com.