jerry-nola@att.net Report post Posted September 4, 2010 We have recently aquired a 2005 Holiday Rambler MH with a 300 ISB Cummins engine. According to the temperature guage, normal running temperature seems to be close to 200 Degrees F. When climbing a grade in warm temperatures, the temp starts to rise above 200. A weak buzzer starts, sounding more like crickets, with no warning light. As the temp rises the intermittent buzzer becomes more pronounced and regular. Upon descending the grade the buzzer gradually goes away. Has anyone else experienced this and found the cause? Thanks, Jerry Howard PS I also have a warning in heavy rain as covered in "WARNING CHIME" However mine is a high pitched beeping sound as opposed to a chime. Share this post Link to post Share on other sites
wolfe10 Report post Posted September 4, 2010 Jerry, By far the most common cause of heating under high load conditions in rear radiator coaches is blockage of the air flow through the CAC (Charge Air Cooler) and radiator. To check on this, access the top of the engine from the bedroom or closet. Shine a strong flashlight inside the fan shroud/between the fan blades. The fan blades sling the dirt toward the perimeter. Look carefully at the perimeter, particularly lower part of the perimeter to verify that it is as clean as the center. If not, clean with garden hose nozzle if just dirt. If any oily deposit, that plus Dawn detergent. Brett Share this post Link to post Share on other sites
