Its been 5 years and I haven't cleaned my car coolant tank, therefore, I decided to use an easy method to clean it.

Things I used in cleaning:

1. H₃NSO₃ - Sulphamic Acid Mixture;
2. Sonax Ultra Cleaner;
3. Dishwasher salt;

It was the hardest to get the results was the yellowness of the coolant tank. Scrubbing is dead useless here, since the yellowness you can see on coolant tanks is the result of a chemical reaction. The only solution is to whiten bleach out the ugly yellow color out of the coolant expansion tank.