Overheating

[harv12]

We have a '07 Winnebago with a 400 HP Cummings Engine and a Allison 3000 MH Automatic Transmission. We noticed recently that the transmission fluid temperature and coolant temperature both were rising while we were on any substantial grade. It never got too hot, but we would pull over and it would cool down quickly while at idle.

I checked all the obvious and just changed all the caps on the coolant reservoir.

If anyone has experienced similar issues please let us know.

Thanks

[homeless]

My problem was the clutch fan!

[Jerry J]

Originally Posted by harv12

<<<< We noticed recently that the transmission fluid temperature and coolant temperature both were rising while we were on any substantial grade. It never got too hot, but we would pull over and it would cool down quickly while at idle.>>>>

If it didn't get too hot then why pull over? What temperatures are you seeing? Was that the high idle setting?
Mine (eng.) will go up to 212° up a grade and down to 199° when the fan comes on. I just manually shift to keep the rpm at 2000 -2100 to keep the temperature in control. I have the EPA-07 engine.

[harv12]

Thanks Jerry,
The transmission temperature would go up from about 180* to 205* on a grade {I can see that through the info panel on the dash} the coolant temperature which usually reads about 1/2 on the dash scale would go up to between 3/4 and the Red hot indicator. I haven't checked it through the info panel yet.

I figured pulling over when seeing those odd readings as smarter than pushing my luck.

We have the Cummings 400 HP engine number CUM ISL03 with the Allison 3000 MH automatic transmission.
I have no idea what the "high idle" setting would be; the tach usually reads about 1500 +/- when were idling. Again, the only time this has been issue is recently when we've been going up a significant grade for more than a few minutes.
Thanks for any input

[Jerry J]

Thanks Jerry,
The transmission temperature would go up from about 180* to 205* on a grade {I can see that through the info panel on the dash} the coolant temperature which usually reads about 1/2 on the dash scale would go up to between 3/4 and the Red hot indicator. I haven't checked it through the info panel yet.
I usually have the LBDU showing the eng. temp, trans. temp, and fuel mileage showing.

I figured pulling over when seeing those odd readings as smarter than pushing my luck.
Good idea.

We have the Cummings 400 HP engine number CUM ISL03 with the Allison 3000 MH automatic transmission.

I have no idea what the "high idle" setting would be; the tach usually reads about 1500 +/- when were idling. Again, the only time this has been issue is recently when we've been going up a significant grade for more than a few minutes.
I think mine reads 1200 rpm at high idle as set by cruise.

[OldChief7155]

I have a CAT 350 with the Allison 3000. Just like any vehicle temps will rise a bit when pulling a grade. If it stays within limits just keep on trucking'!

[harv12]

Thanks Jerry and the rest for all the input! This site has been a real education. I've been in the HVAC / Electrical business for many years and this whole thing has proven to me how little I really know

I haven't seen what the temps will do with the new coolant reservoir caps (radiator, pressure relief and something else), but considering it only happens on a decent grade up, I doubt they're really the issue {though they did need replacing}. I will play with my info panel to see if I can get the trans temp, engine/coolant temp and the RPM's to read out. It seem there's room for three read outs without having to scroll. Driving this BUS is enough for me to be occupied without fidgeting with the toggle

Thanks again and I'll try to keep this thread updated as to what the heck it ends up being.

Thanks again!