Motor runs hot when rpm increase

[sempka]

2000 Holiday Rambler with a 2000 Ford Triton V-10 motor, motor started to run hot when going up hill and the transmission downshifted causing rpm to increase. Replaced the a bad fan clutch the thermostat and had the radiator flushed, drove it about 500 miles and motor started to run hot when rpm increased, replaced the thermostat again based on recommendation from a mechanic. Drove motorhome about 900 miles before problem reoccurred after running about 3 hours that day the motor started to run hot again when the rpm increased going up a hill. I never let the motor get hot enough to get out of the operating range, by slowing down and letting the rpm drop. Any suggestions on where to look next?

[sempka]

Chum lee wrote:

FunTwoDrv wrote:
I wonder if you could be dealing with an air lock somewhere in the system...

Gary

My Ford F53 V10 is rock solid on water temp no matter what I do. (Once warm, it never varies in coolant temperature according to the gauge) The fan clutch does engage on some longer hills though. That said, some engines appear to get hot/overheat if there is air trapped in the cooling system around where the water temperature sensor is located. I don't know if that is an issue with the Ford V10 or not. Without an accurate alternate way to check the coolant outlet temp, you won't KNOW either. I'd suggest you find out before you start servicing/replacing parts.

Chum lee

Getting an OBD plugging to use with FORScan Lite so that I can watch several parameters. Will report back when I have results. Suspect radiator. Filled with new fluid about 1400 miles back and replaced the receiver, it already has lots of black material in the new receiver.

[time2roll]

Easy to boil the thermostat on the stove to verify it opens fully.

[wvabeer]

I have purchased more than one faulty tstat

[Chum_lee]

FunTwoDrv wrote:
I wonder if you could be dealing with an air lock somewhere in the system...

Gary

My Ford F53 V10 is rock solid on water temp no matter what I do. (Once warm, it never varies in coolant temperature according to the gauge) The fan clutch does engage on some longer hills though. That said, some engines appear to get hot/overheat if there is air trapped in the cooling system around where the water temperature sensor is located. I don't know if that is an issue with the Ford V10 or not. Without an accurate alternate way to check the coolant outlet temp, you won't KNOW either. I'd suggest you find out before you start servicing/replacing parts.

Chum lee

[FunTwoDrv]

I wonder if you could be dealing with an air lock somewhere in the system...

Gary

[mowermech]

sempka wrote:

rgatijnet1 wrote:
Were the radiator fins cleaned when the core was flushed?

Yes, they were washed out.

Based purely on experience, I would remove the radiator and have it professionally, thoroughly, cleaned.
Our first motor home was a 1977 Pace Arrow, Chrysler 440 engine. It would overheat going over the Continental Divide. I used radiator flush, washed out the fins as best I could, replaced the water pump, thermostat, fan clutch, belts, etc.
Finally, when it overheated on a mild grade, I went home and decided to remove the radiator for professional cleaning. When I unbolted the A/C condenser, and swung it out of the way to access the radiator, I discovered the fins looked like an adobe wall! The dust and bug guts had plugged it completely. There was no air flow through almost 3/4 of the radiator. Once it was professionally cleaned in a hot tank, no more overheating trouble.

[sempka]

time2roll wrote:
Wow 3 percent putting you at 35 mph is crazy. I would have assumed 5+ percent and some altitude.

Does it feel like it has performance issues? Long shot would be the air filter.

Actually this was in eastern Oklahoma on I-40, and it did put me below the legal minimum speed on a couple of hills.

[sempka]

OLYLEN wrote:
What do you mean getting hot but in operating range. If its in the operating range its NOT hot. Normal operation 190+or-, when climbing with lower gear and 4500 RPM to around 200 + or- then the fan kicks in. you can hear it, soon temp starts cooling with trans temp lagging a bit. Need more info, sounds normal.

LEN

The 3rd time the problem happened after running a total of about 850 miles (after the thermostat was changed out) without any increase in temperature including going up and down hills. On that day the temperature after the motor warmed up stayed normal for about 3 hours running at 65 to 67 mph with the rpm running about 2200. This included going going up and down hills with the rpm increasing from about 2200 to 3500. Going up a hill no worse than some of the others, the themperature started to climb and appeared to be still increasing. It got to the upper white mark eventhough I slowed the motorhome down to decrease the rpm down from 3500 to 2200, before I got the temperature to decrease very slowly back to normal, after that 1st occurrance the temperature would start to climb everytime the rpm increased to 3500.

[OLYLEN]

What do you mean getting hot but in operating range. If its in the operating range its NOT hot. Normal operation 190+or-, when climbing with lower gear and 4500 RPM to around 200 + or- then the fan kicks in. you can hear it, soon temp starts cooling with trans temp lagging a bit. Need more info, sounds normal.

LEN

[time2roll]

Wow 3 percent putting you at 35 mph is crazy. I would have assumed 5+ percent and some altitude.

Does it feel like it has performance issues? Long shot would be the air filter.

[enblethen]

The water pump is doing an adequate job until engine is under load then it does not perform properly.
I would not use a factory style thermostat. Always look for and get a thermostat that fails in the open position.

[sempka]

time2roll wrote:
You mean a Ford gauge actually moves?

Since the thermostat seemed to make some difference... is that a genuine Ford part or just a random part over the counter? At least ask for the premium thermostat.

Certainly if the hoses are original or soft they could be replaced. IMO not much collapses when running 10-15 psi.

The thermostat is a genuine Ford part, the bottom hose doen't appear to be very soft. Yes, the gauge actually moves and depending on long the the rpm stay high, the temperature gauge will move higher or lower in the range.

[sempka]

WE3ZS wrote:
You are only stating "hot" but without actually knowing the real temperatures the engine and trans are getting up to. Having the actual temperatures of both would be a big help in trying to diagnose the problem(s) or verifying that there really isn't a problem.
Get a ScanGauge, Ultra-Gauge or any one of the vast number of OBDII dongles and smartphone apps (like Torque) to monitor the engine and trans vitals.
Being a model year 2000 rig, do the trans cooling lines go into and out of the radiator then into a trans cooler or do they only go straight to the trans cooler? Some of the Super Duty pickups of that era didn't have the ATF flow routed through the radiator, something Ford corrected soon thereafter. Many owners of those trucks have updated them with later model radiators with the ATF cooling circuit for far better trans temp control while towing and hauling heavy loads.

The lower radiator hose appears to be fairly solid, but does not have a wire reinforcement. Am looking at ordering a ScanGauge to confirm the dashboard gauge, The trans cooling lines go direct into the trans cooler.

[time2roll]

You mean a Ford gauge actually moves?

Since the thermostat seemed to make some difference... is that a genuine Ford part or just a random part over the counter? At least ask for the premium thermostat.

Certainly if the hoses are original or soft they could be replaced. IMO not much collapses when running 10-15 psi.