Fan stuck wide open

[Ljwt330]

Originally Posted by 08Navigator

I must really have something wrong...I pulled over on side of highway to check my trailer ...I walked around the back of my coach when I noticed the fan was roaring...I went in and checked temp...was 183...what was making go so fast if the engine was at idle? What would make the fan do that? How is that possible?

I will venture an educated guess, but it is still just a guess as I am not familiar with the exact set up of your fan cooling system.


However, in general, your fan speed and cooling is regulated by an electronic control that opens/closes a valve that regulates pressure in the hydraulic lines to the hydraulic motor control. If that electronic control fails completely, the system defaults to full speed for the fan, whether under load or at idle. It is a safety issue to prevent overheating. This appears to be what has happened. Your temperature of 183* is likely too cool for proper performance as well.


I would suggest you see a shop that deals with your chassis manufacturer and have them inspect the fan regulating system. Often it is a simple replacement control module.

[08Navigator]

Thanks for the input!!!

[jacwjames]

Check your manual, there should be a detailed description of how the fan should work and what temperature it should start speeding up. In my case it starts speeding up at 185F. Normal driving I run ~183F based on my Silverleaf display, climbs to ~190 on hard pulls.

[TR4]

Originally Posted by 08Navigator

I must really have something wrong...I pulled over on side of highway to check my trailer ...I walked around the back of my coach when I noticed the fan was roaring...I went in and checked temp...was 183...what was making go so fast if the engine was at idle? What would make the fan do that? How is that possible?

Sounds normal to me. Remember, you’re pulling off the highway, pulling a trailer. Your engine has a lot of heat built up. You’re now sitting there with the engine running at idle. The water pump is slowly circulating coolant. At idle, it will take time to drop coolant temperature. It will take time before the fan speed drops. This is how my electronic controller worked.

After two electronic controller failures I installed the wax valve conversion. The electronic controller would cycle between 180 to 199. The wax valve was more proportional, keeping the temperature around 186 to 190. On a hard pull, the temperature would go up to 200. The electronic controller was always trying to catch up with temperature. I also saw a small gain in fuel economy.

Bill

[vito.a]

Originally Posted by 08Navigator

I have no idea what size anything is...except the reservoir. which, at max may be 2 gallons...and the lines running to the reservior might be at max -12 so just for coversation...i am thinking the system might be running max 5 gallon per minute...at 1500 psi...so correct me if I am wrong...1500 x 5 / 1714 = approx 5 hp? max?

Check your owners manual and you will see the hydraulic system is much larger. Our Cummins ISX hydraulic system holds 22 gallons of Dexron. The hydraulic pump is quite large and driven off the engine PTO. It drives two very large fans and the power steering.
Fan speed is governed by the engine ECU through a Sauer Danfoss hydraulic fan controller. The fan controller is famous for going bad and then defaulting to full speed.
This is a post with pictures on rebuilding the hydraulic pump. You can see how large it is in the second picture.
http://www.irv2.com/forums/f115/saue...ml#post4895665

[hypoxia]

Originally Posted by TR4

The electronic controller would cycle between 180 to 199. The wax valve was more proportional, keeping the temperature around 186 to 190. On a hard pull, the temperature would go up to 200. The electronic controller was always trying to catch up with temperature. Bill

Interesting statement. My 15L ISX 600 has a 195° thermostat and runs 195°.
On a long climb may go just over 200°. I don't think I have ever seen more than 205° with the Sauer Danfoss Electronic Controller in normal operation at 53,000 pounds on a hot day.

The engine ECM sends a PWM signal to the Sauer Danfoss Electronic Fan Controller (FDCA) which in turn regulates the hydraulic flow to the fan varying the fan speed. If your engine temperature was varying 20° it leads me to wonder if there was more to the problem than just the FDCA. Regardless, the wax valve cured your problem by eliminating all electronics.

[TR4]

Originally Posted by hypoxia

Interesting statement. My 15L ISX 600 has a 195° thermostat and runs 195°.
On a long climb may go just over 200°. I don't think I have ever seen more than 205° with the Sauer Danfoss Electronic Controller in normal operation at 53,000 pounds on a hot day.

The engine ECM sends a PWM signal to the Sauer Danfoss Electronic Fan Controller (FDCA) which in turn regulates the hydraulic flow to the fan varying the fan speed. If your engine temperature was varying 20° it leads me to wonder if there was more to the problem than just the FDCA. Regardless, the wax valve cured your problem by eliminating all electronics.

I think they made changes to the SD controller. My controller did not take input from the ECM, only coolant temperature, intake manifold air temperature and A/C trigger signal.

Bill

[jdw1]

Originally Posted by TR4

I think they made changes to the SD controller. My controller did not take input from the ECM, only coolant temperature, intake manifold air temperature and A/C trigger signal.

Bill

So, how many leads go into your SD controller?

[08Navigator]

Originally Posted by vito.a

Check your owners manual and you will see the hydraulic system is much larger. Our Cummins ISX hydraulic system holds 22 gallons of Dexron. The hydraulic pump is quite large and driven off the engine PTO. It drives two very large fans and the power steering.
Fan speed is governed by the engine ECU through a Sauer Danfoss hydraulic fan controller. The fan controller is famous for going bad and then defaulting to full speed.
This is a post with pictures on rebuilding the hydraulic pump. You can see how large it is in the second picture.
https://www.irv2.com/forums/f115/sau...ml#post4895665

Thanks Vito....I will look in the manual...I just have the one fan.. I would like to keep the temp at the 180ish range, Convienced that is free HP. I guess all I will need is different Thermo Hydraulic valve? Maybe one that goes to full open at 185...and a lower thermostat for the engine (I am assuming the standard thermostat is 180) for the engine. Maybe I can get a 170 ish?

[hypoxia]

2007 Monaco Fan Controller Wiring Harness

https://www.irv2.com/forums/download...do=file&id=384

[Windecker]

I recently had both of my thermostats fail on my DD60 which caused my engine temps to rise roughly 10 degrees over normal. The first indication was the temps increasing a little at a time over several thousand miles.

The give away was the screaming cooling fan. I never over temped or had performance issues but I noticed my fan was running full speed almost constantly (once warmed up a little).
When I would arrive home, it would run for about 15 minutes screaming till it finally would cool down. Temp on the gauge was only up a little. Normally once home, it would already be cooled down from the highway since I live 5 miles, back country roads from the exit.

How I tracked it was feeling the outlet hoses of the radiator with the fan on full. I had very hot inlet hoses and room temperature outlet hoses. Meaning, the system was cooling too much. This told me, either a restriction in the cooling system or failing coolant pump.

Swapped the thermostats and it all was happy again.

Second point, I lost 1+ MPG when this was all going on. Starting at around 7 MPG normal average, a 1-1.3 MPG loss is huge.

Third, a screaming fan is not something to ignore at all. Yes, maybe to get home or to get it serviced but I would not ignore it.

Those fans gobble horsepower and are plastic blades. Blades that only last so long and if it lets go, you will almost for sure need a new radiator also.

No idea if any of this is relevant to your situaiton but I will say, if you normally do not hear your fan running full on, something has changed.

And like Vito said, this is not a small 2-5 gallon system. It is a massive cooling system holding roughly 20 gallons of hydraulic fluid with a pump pusing over 3000 PSI at a very high volume.

Cummins ISM engines normally have 2 fans.
Cummins ISX engines normally have 1 fan
DD-60 normally 1 fan
Cummins ISL normally 1 fan (but I am not confident on the ISL setup much).

Hope that helps...

Windecker

Originally Posted by 08Navigator

I must really have something wrong...I pulled over on side of highway to check my trailer ...I walked around the back of my coach when I noticed the fan was roaring...I went in and checked temp...was 183...what was making go so fast if the engine was at idle? What would make the fan do that? How is that possible?

[TR4]

Originally Posted by jdw1

So, how many leads go into your SD controller?

Eight
12v pos
12v neg
(2) A/C
(2) coolant sensor
(2) air intake sensor

Bill

[08Navigator]

Originally Posted by Windecker

I recently had both of my thermostats fail on my DD60 which caused my engine temps to rise roughly 10 degrees over normal. The first indication was the temps increasing a little at a time over several thousand miles.

The give away was the screaming cooling fan. I never over temped or had performance issues but I noticed my fan was running full speed almost constantly (once warmed up a little).
When I would arrive home, it would run for about 15 minutes screaming till it finally would cool down. Temp on the gauge was only up a little. Normally once home, it would already be cooled down from the highway since I live 5 miles, back country roads from the exit.

How I tracked it was feeling the outlet hoses of the radiator with the fan on full. I had very hot inlet hoses and room temperature outlet hoses. Meaning, the system was cooling too much. This told me, either a restriction in the cooling system or failing coolant pump.

Swapped the thermostats and it all was happy again.

Second point, I lost 1+ MPG when this was all going on. Starting at around 7 MPG normal average, a 1-1.3 MPG loss is huge.

Third, a screaming fan is not something to ignore at all. Yes, maybe to get home or to get it serviced but I would not ignore it.

Those fans gobble horsepower and are plastic blades. Blades that only last so long and if it lets go, you will almost for sure need a new radiator also.

No idea if any of this is relevant to your situaiton but I will say, if you normally do not hear your fan running full on, something has changed.

And like Vito said, this is not a small 2-5 gallon system. It is a massive cooling system holding roughly 20 gallons of hydraulic fluid with a pump pusing over 3000 PSI at a very high volume.

Cummins ISM engines normally have 2 fans.
Cummins ISX engines normally have 1 fan
DD-60 normally 1 fan
Cummins ISL normally 1 fan (but I am not confident on the ISL setup much).

Hope that helps...

Windecker

Wow, never thought that the fan would break apart...maybe I would be better off just putting a few automotive style electric fans on and canning the the entire hydraulic mess, sounds like it would be significantly more efficient? Much simplier and less stuff to break or fail plus nothing gobbling up HP. Thanks for the input!!

[jdw1]

Originally Posted by 08Navigator

Wow, never thought that the fan would break apart...maybe I would be better off just putting a few automotive style electric fans on and canning the the entire hydraulic mess, sounds like it would be significantly more efficient? Much simplier and less stuff to break or fail plus nothing gobbling up HP. Thanks for the input!!

Just remember that fan also draws air across your aftercooler, not sure I’d go that route. JMO