Originally Posted by PanJH
I spray the engine/tranny and the radiator/CAC with Simple Green HD ( safe for aluminum on the radiator) diluted at about a 1:3 ratio . Let it sit for 5-10 minutes and hose it off. Do it a couple times a year and keeps everything clean. Haven't had to use the pressure washer on it yet.
Your method using Simple Green HD is what is recommended by Freightliner for cleaning the radiator.
"RADIATOR CLEAN OUT METHODS BY FCCC
Dear Campers it has come to the attention of FCCC that the cleaning method suggested of the Radiators and Charge air cleaners are being questioned because of the radiators being made of ALUMINUM and PLASTIC and the cleaning product suggested. (Simple Green).
This product Simple Green is a effective cleaner and it is also biodegradable and when the Directions are followed limiting the contact time and rinsing well, Simple Green will not discolor or oxidize aluminum and is non corrosive, this product has been used for many years to clean aluminum, with no ill effects, it does not provide corrosion protection.
In military testing the product did cause discoloration and some oxidation when allowed to soak for many hours. It should also be noted that the mixture given is 3 parts hot water and 1 part simple green. Put this mixture in portable one gallon bug sprayer and apply to the outside of the radiator and to the outside of the charge air cooler and rinse thoroughly, repeat this process till rinse water becomes clear.
We have contacted the makers of simple green, Sunshine Makers, Inc about this and they have responded to FCCC with this information below:
Because of the possibility of misuse or improper rinsing we have developed another product that has been tested on metals, alloys, plastic, rubber, etc. This is the best retail product that we offer for cleaning aluminum. The product is called Simple Green Pro HD. It is readily available at Home Depot. This product formulation is based on the same formula as our Extreme Simple Green Aircraft & Precision Cleaner and is actually faster acting, more aggressive and also provides corrosion protection during the cleaning process. The dilution ratio will be the same that you are currently using, and it does require a rinse, but it is much safer for aluminum. This product is also safe for plastic, rubber, painted and gel coated surfaces, carbon fiber, and will not discolor anodized aluminum.
They recommend the use of Simple Green Pro HD, you will be able to recognize it by the purple color and Label at Home Depot.
Still use the portable bug sprayer and keep the solution mixture the same, 3 parts hot water and 1 part Simple Green Pro HD. spray on the outside of the radiator and spray on the outside of the charge air cooler and rinse thoroughly repeat as necessary till clear water comes out. Hope this will help settle the debate on Simple Green usage on Radiators and charge air coolers."