rsmolway@comcast.net

I have a 2000 DP with a Cummins 300 ISC. I do not know when the fluid was last changed. I called TWO Cummins service centers in Fl. Ctr #1 told me it needed a Fluid change and possibly a flush. ..[without seeing the coach] He said to expect the cost to be $500+.. Ctr #2 told me to drain a little fluid to see if was dirty and check the Ph. If the fluid was dirty it needed to be changed. If not, don't drain the radiator. If the Ph was off and the fluid was clear it only it needed an additive. My Cummins book claims that it needs to be done every two yrs or 24,000 miles When I checked the fluid it was clear [ green color] and the Ph was perfect. My question is which Cummins service center should I believe ?? To Flush or not to Flush..that's my question ? Thanks Capt. Ron

We have a 33,000 lb GVW coach with a 300 Cummins ISC Engine. At first we kept it at 55MPH and achieved 10+ MPG. At this speed we turned 1400 RPM. At a Cummins seminar I was told that I could damage the engine if I travelled below 1650-1700. Know we speed along at 65+ and achieve only 8MPG. We seem to spend most of our time in the passing lane. Did anyone ever hear of this advice or should I slow down a save a few bucks ?? Capt. Ron