Step 6:

6: Next, after blocking the wheels for safety, we crawled under the rear of the coach on the passenger side and sprayed the radiator stack from this angle as much as we could. The radiator fan is in the way so you will have to change the position of your sprayer to reach as much of it as possible while realizing that in most coaches you may be spraying the charge air cooler or air conditioner coil and not the radiator directly.