Also, if you have a greasy or oily chassis, go rent a Hotsy.
So I didn't rent a Hotsy, but I did manage to run a hose from the laundry room hot water line to the pressure washer, and wow what a difference! Hot water is the way!
I'm using a foam cannon loaded with a mix of Dawn, purple power, and car soap, and the hot water suds being blown into every corner and crevice really paid off.
Getting in there and agitating everything with a long handled brush also goes a long way.
The hot water cuts through crud and grease like a laser beam. I can actually tell what shape my knuckles and birfs are now.
I went ahead and scrubbed all the stuff I've taken off so far too.
I think I'm going to pay to have the radiator professionally cleaned and refinished.