Pressure washing a radiator

[Robert92867]

Not all radiators can withstand a Sunjoe 1700 psi pressure washer.  This particular radiator is a 2015 CGI aluminum 3-core model for a rear radiator Monaco.  The 4-core models are more $ and harder to clean.

[1nolaguy]

Pressure washers should never be used on finned radiators, especially those with aluminum fins. Even a water stream from a garden hose nozzle can damage aluminum fins. I was advised that the best way to clean the radiators( and also your A/C coils) is with lots of running water and from the side that air usually flows through. For radiators that is from the out side toward the engine. I do this every time I wash the rig. If your coils are really dirty water them down and then spray on a mix of water with dawn and distilled vinegar. let it soak for 10 minutes then rinse and repeat at needed. Alternately you can use a commercial coil cleaner which come from big box stores in a spray foam or from an HVAC supply house, usually in a concentrate that is to be diluted with water. Spray on, let soak about 10 minutes, rinse and repeat as needed.

I find the best way, once thoroughly cleaned, is to rinse with plenty of water regularly and then once or twice a year I do the Dawn/vinegar thing as noted above. 

Also, if you have fins that are pushed over use a fin comb or stiff plastic bristle brush to "comb" the fins back straight. It is amazing how much heat exchange efficiency can be lost by a coil when fins are bent over, even partially, and restrict air flow.