Over heating issue

[iamalienru]

I have a 1998 American Eagle has about 60 k miles on it. it over heats when climbing a sustained grade. I know it is heating because when it got hot it was boiling over. as soon as i get off the grade it cools down to normal operating temp of 190 and it does it pretty quick. I have a new radiator not more than 9 months old. it has a side radiator i can see the fan working. just can't figure it out. yes it has the proper fuilds that i top off before every trip If you have any ideas please let me know thanks

[iamalienru]

Thank you for all the good info I am sure I purged the system when refilling the system I called Spar ten and they told me I could have a problem with the flow valve to the hydraulic fan it is an aluminum box mounted on the frame that has four lines coming in and out of it ..it sends fluid to the fan and power steering pump the steering line is seperart from the fan line they said to clean the values with brake fluid I am also going to add an external electric fan so I have a push pull system if that doesn't fix the problem don't know my next move down shifting is done when it gets hot cools it down enough to keep moving slowly but I want tow my boat and I don't want to worry too much about heat going slow is not a problem I want to get it right

[Kidoo]

Mine was overheating after I replaced the Radiator. I done the replace myself but had the core rebuilt. I tought the rebuilt was the problem because the fin and tubes where not the same, they where actually bigger to cool better and they where industrial / big truck type instead of the normal automotive type they have in many MH.

It came out that it was air in the system, it would warm up quickly when going up hill. The coolant lines have a long way before they get to the front heater and air has all kind of places to hide and creates air lock as I understand.

I ran mine for a good hour on a steep parking so the back was higher (DP) and the reservoir was higher, air bubbles goes up, the heater to full hot and the reservoir cap removed, coolant normally runs all the time through the little line just bellow the cap reservoir and it purge by itself.

The radiator shop told me it could take a long time to get rid of air trapped in a big system. It might not be your problem but I would give it a try.

Do you have an extra heater for the MH or a system for hot water? Air can be in there too.

[mabynack]

A couple of suggestions. A bad cap can cause overheating.

I've also seen shops install the fan blade backwards.

It's possible that something is obstructing air flow through the radiator.

Try checking the temperature on different parts of the radiator when the vehicle is warm. Sometimes the coolant passages are blocked or something is obstructing the air flow. Hot spots or cold spots indicate a problem with the radiator itself.

[RLS7201]

Had the very same issue with my old 95 Ford F53 chassis. The replacement radiator has 25 percent less fins then the old radiator. 15 fins per inch ver. 20 fins per inch.
Is there a possibility you could check the fin count.

Richard

[Kayteg1]

You are not saying what grade, but I know that in California whenever you drive, sooner or later you will approach 7-15 miles long grades.
No vehicle has cooling system design to keep lower temperatures on such grades if you keep gas pedal on the floor.
220F is not bad IMHO, but you might try to manually downshift at the bottom and go slower with higher rpm for better cooling efficiency.

[jurob]

How much grade? What gear, rpm and mph?

[Gjac]

Does it still boil over after all the changes you made or does just the gage read high now? Is the gage reading lower now or still the same as before the changes?

[iamalienru]

Fan is pulling air like a hurricane speeds up with rpms

[iamalienru]

Hello again still having the heating problems changed thermostats pulled water pump changed hydraulic fluid and filter new air filter runs at 185 in the yard out on the road after running about 40 min. it takes a hill and runs up to about 220 new radiator on surge tank 16 psi I am at a loss may time to change out the sending unit at a loss

[iamalienru]

thanks that is some good information i will try it.

[redguard]

iamalienru wrote:
i changed the radiator because i picked up a bolt on the freeway that caused a small leak in it. i have changed the radiator cap. fan speed looks to be fine rotating at high revolution. i did notice that the site glass to the fluid tank had a slow leak from its O ring i replaced it now i just have to get warmed up and pull a grade with it because it won't get over 185 degrees just running it. when it heated up i was pulling with my boat so i may have to recreate the situation any grade would send the temp to unsafe heat level. As soon as i got off the grade temp goes right back down to 190 thank you for all of the information you all provided

all Diesel MH,s will run considerable hotter when loaded pulling a steep hill.Your,s getting to the boiling point indicates you may have a combustion leak(maybe) or your fan is not engaging when it should and not full force.There is a fan control switch right at the fan hydraulic drive unit.DISCONECT the wire harness.This will default your fan to high speed.Try it like that and see how the temp goes
believe me its certainly not as simple as a rad cap or anything silly like that

[iamalienru]

i changed the radiator because i picked up a bolt on the freeway that caused a small leak in it. i have changed the radiator cap. fan speed looks to be fine rotating at high revolution. i did notice that the site glass to the fluid tank had a slow leak from its O ring i replaced it now i just have to get warmed up and pull a grade with it because it won't get over 185 degrees just running it. when it heated up i was pulling with my boat so i may have to recreate the situation any grade would send the temp to unsafe heat level. As soon as i got off the grade temp goes right back down to 190 thank you for all of the information you all provided

[tropical36]

iamalienru wrote:
I have a 1998 American Eagle has about 60 k miles on it. it over heats when climbing a sustained grade. I know it is heating because when it got hot it was boiling over. as soon as i get off the grade it cools down to normal operating temp of 190 and it does it pretty quick. I have a new radiator not more than 9 months old. it has a side radiator i can see the fan working. just can't figure it out. yes it has the proper fuilds that i top off before every trip If you have any ideas please let me know thanks

Have you cleaned or had it cleaned in a while. These radiators require periodic cleaning with a solution of some sort and a water hose and you might want to research the many existing threads concerning this.

[doxiemom11]

We just had this with our Jeep (older). Replaced the radiator cap ($4.99) and the problem stopped. The old cap wasn't doing it's job anymore. Love these cheap fixes.