Forum Discussion

AZCowboy's avatar
AZCowboy
Explorer
Nov 11, 2013

Overheating when climbing hills

We are new to RVing. We purchased a 92 Fleetwood Bounder, 34 ft. It has a Cummings engine and Allison Transmission. It runs excellent EXCEPT for when climbing hills. The temperature gauge sits at 180 degrees until we start climbing and then depending upon the grade it can raise up to over 210 degrees. Within 5 minutes of pulling over, the temperature will drop back to 180 degrees and if we idle longer it will drop down to 160. We've replaced the thermostat, raidiator cap, had the radiator rebuilt, replaced all the hoses and fan belts. We also of course had all the radiator fluid replaced when we replaced the hoses and rebuilt the radiator.

Any other suggestions?
Class A
  • hershey's avatar
    hershey
    Explorer
    Nov 11, 2013
    I agree with the above post. 210 is not too hot when climbing a hill. My Cummin's will hit that number in very hot weather climbing.
    Normal is about 185-190.
    Remember to reroute the blow by tube from the top of the engine to the bottom of the radiator. It will coat the radiator with an oil film and of course attract dirt and dust until it plugs the fins on the radiator.
    Happened to mine at only 30,000 miles. Did the reroute and now have over 70,000 miles and still clean and runs cool.
  • Sully2's avatar
    Sully2
    Explorer
    Nov 11, 2013
    rgatijnet1 wrote:
    It sort of sounds like everything is NORMAL. With the usual 15 pound radiator cap, the boiling point of your antifreeze is in excess of 250 degrees. If the temperature only raises to 210 when you are climbing a hill, it sounds like everything is still well within the normal range of operation. You can throw a lot of money at it and install a larger radiator and maybe a separate transmission cooler but to me it sounds like you really do not have a problem.


    I have to agree from only reading text.
  • Sully2's avatar
    Sully2
    Explorer
    Nov 11, 2013
    AZCowboy wrote:
    We are new to RVing. We purchased a 92 Fleetwood Bounder, 34 ft. It has a Cummings engine and Allison Transmission. It runs excellent EXCEPT for when climbing hills. The temperature gauge sits at 180 degrees until we start climbing and then depending upon the grade it can raise up to over 210 degrees. Within 5 minutes of pulling over, the temperature will drop back to 180 degrees and if we idle longer it will drop down to 160. We've replaced the thermostat, raidiator cap, had the radiator rebuilt, replaced all the hoses and fan belts. We also of course had all the radiator fluid replaced when we replaced the hoses and rebuilt the radiator.

    Any other suggestions?


    Hill climb in a LOWER gear...thereby causing engine RPM to run higher and fan to spin faster....getting more air thru the radiator. DONT depend on the auto trans to know when you need to downshift....YOU do it manually
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Nov 11, 2013
    It sort of sounds like everything is NORMAL. With the usual 15 pound radiator cap, the boiling point of your antifreeze is in excess of 250 degrees. If the temperature only raises to 210 when you are climbing a hill, it sounds like everything is still well within the normal range of operation. You can throw a lot of money at it and install a larger radiator and maybe a separate transmission cooler but to me it sounds like you really do not have a problem.
  • WyoTraveler's avatar
    WyoTraveler
    Explorer
    Nov 11, 2013
    You said you had radiator rebuilt. Did you know that some of the larger radiator shops custom size when they rebuild? Sometimes as much as 50% larger. Cost is very little extra.
  • YC_1's avatar
    YC_1
    Nomad
    Nov 11, 2013
    I would replace the thermostat again. At least pull it out and put it in hot water to see if it opening fully.

    Rear or side radiator? If side radiator does it have a two speed mode?

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