Yahoo Message Number: 63832 (http://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/63832)
Last year our engine heated up going on Hwy 50 in Nevada and it stopped on us before we reached the top of the hill. Afuer a few hours we were able to start the engine and go to the nearest RV Park for the night. The next morning after talking with the Cummins dealer in Elko, NV we drove on into Elko and they found the radiator partially clogged and cleaned it thoroughly and we were on our way again. Since that time the engine overheats quite quickly going up any grade while towing our Explorer. We have changed the engine belts, replaced the Modulator on the fan and the high and low temperature switches. Any suggestions as to why this is happening? Did we damage the engine on the original heating up? What should we look for in trying to hunt down the problem? Should I have the compression checked on the engine? The engine has 47,000 miles on it.
Yahoo Message Number: 63834 (http://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/63834)
Did you down shift into a gear that allowed the engine to maintain high RPM and back out of the throttle a bit? At 47000 the engine is almost broken in. How hot does the transmission run? It can help the engine to overheat if it is running hot. Some will tell you to have the engine fan RPM checked to make sure it is turning at full speed. Maybe time for a new thermostat. Possible the overheat did damage it. How hot is the outside air temp. when you overheat. Can make a big difference. Have you taking a good garden hose and washed out the radiator. Right conditions can plug one quick, i.e. dusty roads. Since this was the first problem, I would go there first again. Have someone take a light on the backside of the radiator and have eyes in front and see if the light comes through without any blocked sections. Safety shut off is to protect from engine damage. How hot was it when it shut off?
You have done a lot and spent some big bucks. A new thermostat would be a cheap try.
Good luck on finding it.
Leonard Kerns
97' Magna 5418
Yahoo Message Number: 63841 (http://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/63841)
Thanks Leonard,
I always downshift to try to keep the RPMs up but it was a 97 degree day, I may not have gone beyond 2500 RPMs. The transmission runs a lot cooler than the engine, maybe 195 or so. The engine was at 225 when it shut down. I did have the radiator checked this last July again and it was clean. The one thing I haven't checked is the thermostat, you would think the people that replaced the high/low switches and the modulator would have thought of that. Thanks, if you get anymore ideas, let me know.
Jim
Yahoo Message Number: 63844 (http://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/63844)
Your transmission is running very cool. That says the power train is not working really hard. Engine and trans should run close to same temp. A thermostat that does not restrict flow can cause overheating as the water moves so fast through the radiator it does not have time to loose the heat. A thermostat that does not open all the way can cause overheating by stopping the water from flowing fast enough. Some diesels have a gasket the thermostat seals against. They can go bad causing overheating as well. If the thermostat does not do it, then the next odd ball to check would be the water pump itself. Some times wired things can happen like the impeller starts to come loose and spin on the shaft, not circulation the water enough under load. This usually will cause a water leak at the pump weep hole, but not always.
Hope it is a simple thermostat.
Leonard
Yahoo Message Number: 63898 (http://groups.yahoo.com/neo/groups/Country-Coach-Owners/conversations/messages/63898)
I Agree with Leonard, Working on Cat Diesels in my other life rare but I have had Impellers loosen up on Water Pumps, T Stat is a must, Even if T Stat is open all the time this wont allow to much coolant to pass through this to is another purpose as its a flow restricter I had a tough time learning this in Cat school fought my instrutor and lost. Remember the sole Job of a Thermostat or Regulator as us Cat people call it is to allow the engine to warm up ASAP to operating temp then its opens to a set clearence. Cool tranny temp is a flag if the temp gauge is accurate. When I troubleshoot a overheating problem we are trained on proper procedure doing troubleshooting is proper steps. 225 Deg. is the Max temp the engine can handle before a forced shutdown. Most likly you may not of had severe engine damage for this shutdown. Cummins has the proper tooling the correctly repair your issue. BTW I also have worked on Cummins diesels. Feel free to E-Mail me off line as Im and owner of a 330 C8.3 99 Allure 30356. I use a surface heat gun or probes with temp gauges to measure coolant entering and leaving the radiator and a good 10 degrees or more in/out difference with the fan at rated speed!!! should be seen. Gook Luck, Ken Retired Cat engine Tech. I always like to put coaches on a Dyno and connect Temp/Pressure gauges and or the Laptop. I get slack on this but I am trained in this.