John, I guess we measure good results by the temp gauge. I noticed that the temp gauge was alittle high, so I used the garden hose, with a fire hose nosel on it, put it right up against the rad, and hosed it out, from both directions. After that the temp went back to normal position.
I think the main cause of ours was that the exhaust was turned straight down, and when driving into gravel lots, it would stir up the dust, then the fan would suck it into the rad. I turned the exhaust just alittle to the right, about a 45 degree angle, and have not had that problem anymore, but I still have a dust collection problem on the back of the coach though. kevin