Ford 460 motorhome running hot

"As a result of this, I am a believer in using only distilled water with a radiator."


Assuming that you mean distilled water MIXED 50%/50% with the appropriate antifreeze/coolant? (see owners manual)

Using deionized, RO (reverse osmosis) or, bottled drinking water is also fine as long as it is mixed with the appropriate coolant.

"Also, I tried two flushes of radiator flush. This did nothing and I do not believe it can attack sediment issues. Waste of money."

Agreed there. Most over the counter radiator flush additives are worthless if you are trying to dissolve hardened internal radiator scale. They work if you get oil/fuel/ATF in the coolant, but, so does flushing with soap and hot water. Save your time/money.

Chum lee

Due to the perception of low performance I would have a compression check performed on all cylinders.

maillemaker wrote:
I just went through an overheat problem with my E350 RV with 460.

My radiator looked like Yellowstone National Park inside. When it's cool, pull the radiator cap and look inside with a flashlight. You may need to drain off some coolant to be able to see the tops of the core tubes (assuming your radiator is a top-to-bottom cored radiator). On mine, there was a mineral deposit around all the cores, and many of the cores were partially or fully plugged. This was the cause of my overheat.



Unfortunately we were on a long trip (600 miles) and we limped it home at 50 MPH with the temperature gauge very near the high end all the way home.

I am pretty sure this cooked my PIP sensor, my Engine Temperature Sensor, and my Catalytic converter, which all failed in short order after this.

The fix for the overheat was a new radiator. I put in an aluminum one. You can see a thread on my repair here:

https://www.ford-trucks.com/forums/1543596-suggest-a-radiator.html

Aluminum radiators have superior heat transfer properties but are susceptible to galvanic corrosion, so I recommend using a zinc sacrificial anode with one. There are details on this in the above thread.

As part of this, I installed a dual temperature gauge to monitor the coolant temperature and transmission fluid temperature.

My engine temperature is now rock-steady at 188-195F.

As a result of this, I am a believer in using only distilled water with a radiator.

Also, I tried two flushes of radiator flush. This did nothing and I do not believe it can attack sediment issues. Waste of money.

I considered having the radiator "rodded out" but it is very hard to find shops anymore that can actually rod out or re-core radiators. And even if you do, there is the risk that the thin metal somewhere will start leaking anyway. If your radiator is original, it's 31 years old so it's probably best to replace it (if it is the problem).

Another thing to check is your fan. If it's thermal clutch controlled it could be bad. Check YouTube for how to do this.

Also check your lower radiator hose to make sure it is not collapsing when the engine revs. If so, this will cause a flow restriction.

If you have to run in an emergency and you have engine heat in the RV house turn it on full blast. This is a secondary radiator and will dump some heat into the house. Of course the house will be hot as hell back there so open your roof vents.

Steve

Hey thanks for the great info!! I will check into the radiator this evening and see if I can see deposits. I will also look into your other thread and see what the process is. This is still a possibility I have not fully ruled out.

I still need to check for the muffler possibility, but I do have my own temp probe and gauge installed so I know the temp is verified. Even when running for hours it wont go over 220, but ideally it shouldnt be much over 200. I can keep it close to 200 if I am not doing a lot of stop and go and hills and working the engine more.
I really dont have the money to start installing additional fans and such nor should I really need to. Simply, the engine shouldn't be running this hot, and the lack of acceleration and power under load leads me to believe there is a seperate issue causing the engine to run inefficiently.
I also think there is a very small leak in the exhaust manifold on the passenger side, and will be getting thermo-steel for it but I doubt it would be causing this. It is a pretty small leak, maybe pencil lead size near one of the mounts.
The 02 sensor was definitely bad as it idles and runs better since replacing. The fuel pressure sensor fixed the not starting when hot issue. Oil pressure is right where it needs to be after pump and crank replacement.
I'm wondering if a lean fuel condition from a faulty pump could be causing the engine to run hot and lack power.
The radiator drains very well as I saw when removal and fluid flush/change. Though I didnt blast it out. The thermostat seems to kick in around 180 I think if I recall correctly and will maintain at or below 220 at the moment even driving in 90+ degree heat for over an hour.
Definitely minimal driving of the motorhome, but to be clear on my situation this is my home and only vehicle aside from peddle bike, and it has to be moved on occasion. Just keeping it to short jumps at the moment to minimize heat build-up.

I just went through an overheat problem with my E350 RV with 460.

My radiator looked like Yellowstone National Park inside. When it's cool, pull the radiator cap and look inside with a flashlight. You may need to drain off some coolant to be able to see the tops of the core tubes (assuming your radiator is a top-to-bottom cored radiator). On mine, there was a mineral deposit around all the cores, and many of the cores were partially or fully plugged. This was the cause of my overheat.



Unfortunately we were on a long trip (600 miles) and we limped it home at 50 MPH with the temperature gauge very near the high end all the way home.

I am pretty sure this cooked my PIP sensor, my Engine Temperature Sensor, and my Catalytic converter, which all failed in short order after this.

The fix for the overheat was a new radiator. I put in an aluminum one. You can see a thread on my repair here:

https://www.ford-trucks.com/forums/1543596-suggest-a-radiator.html

Aluminum radiators have superior heat transfer properties but are susceptible to galvanic corrosion, so I recommend using a zinc sacrificial anode with one. There are details on this in the above thread.

As part of this, I installed a dual temperature gauge to monitor the coolant temperature and transmission fluid temperature.

My engine temperature is now rock-steady at 188-195F.

As a result of this, I am a believer in using only distilled water with a radiator.

Also, I tried two flushes of radiator flush. This did nothing and I do not believe it can attack sediment issues. Waste of money.

I considered having the radiator "rodded out" but it is very hard to find shops anymore that can actually rod out or re-core radiators. And even if you do, there is the risk that the thin metal somewhere will start leaking anyway. If your radiator is original, it's 31 years old so it's probably best to replace it (if it is the problem).

Another thing to check is your fan. If it's thermal clutch controlled it could be bad. Check YouTube for how to do this.

Also check your lower radiator hose to make sure it is not collapsing when the engine revs. If so, this will cause a flow restriction.

If you have to run in an emergency and you have engine heat in the RV house turn it on full blast. This is a secondary radiator and will dump some heat into the house. Of course the house will be hot as hell back there so open your roof vents.

Steve

You replaced the cat converter. Is it the correct size?
How is the muffler?
It could be a possible (clogged) exhaust problem.

pull radiator and have cleaned inside, change thermostat, add fan in front of radiator. and get a real temp prob and find out what the real temp is. DO NOT run it any more or your going to cause unrepairable damage.