engine motor fan not working

[Flyinhy]

4 hours ago, waterskier_1 said:

Does your home brew controller modulate (vary the speed) of the fan or is it simply On/Off?  

  -Rick N.

No, it's simply on off. I know it's not the best solution but it's better than the fan wide open all the time. I've looked other options but money is tight and for now this works. Once this job is over and I get back to home base I will be able to get a friend to hook up insite and see what's going on with my ecm. 

Earlier in the year I had discussed this with Ivan and another member named Melvin. Melvin had contacted source engineering and they came up with a way to solve the variable fan speed. 

 

 here is an official description of the solenoid valve function, just like Melvin described based on intake manifold temp:

 

Motorhomes equipped with an ISM engine have an electric over

hydraulic override control valve. The override valve is located at the lower

rear corner of the radiator package. This valve is a normally closed valve

which is plumbed parallel with the thermovalve. It performs the same

hydraulic signal function as the thermovalve, but is electrically controlled by

the ISM engine. The ISM engine monitors intake manifold temperature. 

 

The electronics of the ISM engine control an 87a relay located in the rear run box

marked Hyd. Fans. When intake manifold operating temperatures are normal,

the electronic engine energizes the coil of the relay. This energizes the coil of

the override valve and the hydraulic fluid signal flows through the override

valve to the thermovalve. If the ISM engine detects an over temperature condition of the intake manifold, the coil of the 87a relay is deactivated. Power

to the override valve is removed, hydraulic fluid flow signal is stopped and

internal spool of the switching valve moves to full open position. The high

pressure fluid is directed to fan motors cooling 

Edited June 27, 2023 by Flyinhy

[Bill R]

1 hour ago, waterskier_1 said:

Most users want the fan speed to reflect the coolant temperature and not the engine (or transmission) RPM.  

My research on Thermo Wax Valves for our coaches is that they do not begin to open until around a calibration temp of 190F-200F.   And are wide open at +10F which puts the fan operation at WAO.  The thermo wax valve operation does not adjust fan RPM based on coolant temperature until those calibration temps. 

The Sauer Danfoss controllers are PWM PID controllers with variable and switch inputs.  They are advanced controllers that take into account coolant and air intake temps and possibly other inputs.  Also Dash AC compressor input and perhaps other switch inputs. 

The system I am using is replicating very closely the thermo wax valve operation.   If someone is looking to replace the SD Controller with a Thermo Wax Valve, this option very similarly replicates what the thermo wax valve will do.   If my motor controller goes out, I am out $15 for a new one.   I believe a thermo wax valve is around $300 plus.

The OEM replacement approach was one I considered, but the prices I saw led me to this much lower cost operation that performs very well based on many miles of operation.  Maybe @Jdw12345 can share how much his new SD controller was.

Plenty of options for ALL to ponder.  SOOOO much better than WAO all the time.

[Lionel blain]

thanks to everyone that has given great info on this subject, there is a lot to consider going forward. not sire which way i will go but hopefully I will figure something out and keep everyone informed as to the results.  Thanks again

[Jdw12345]

When I replaced my controller, I replaced the controller and the valve, if my memory serves me correctly I believe it was right around $1200.00 for the complete unit, took me lees than 10 minutes to install. I believe the controller without the valve was in the neighborhood of $800.00.

[Lionel blain]

jdw12345 where did you get the replacement controller? I'm in Canada and i looked into replacing the sd valve but they wanted $5000, which is out of my price range.  

thanks Lionel

[Jdw12345]

Brendenson Fluid Power, Andrea in Waukegan IL, (847) 689-1570

 

  Don’t know if she is still there but a super gal to work with, I attempted to get it from Brendenson in Tulsa I believe and since I’m in Minnesota they suggested I contact the outlet assigned to my location, they respect territory, my wife is a commissioned sales rep so I actually appreciated that!

[Jdw12345]

Today, working our way across South Dakota from Hot Springs to Lusk Wy I stopped at Mule Creek Junction to use the restroom, it was almost 100* the wind was blowing everything was running hot, engine, transmission, the dash air was running on max, fan on high, when I jumped out and headed in the fan was running, I thought maybe my fan controller took a poop on me, when I returned to the coach the fan was still running fairly fast, I jumped in turned the dash AC off and when I got back out and to the rear of the coach the fan was winding down. Turned the AC on and headed to Lusk Wy when we checked in at BJ’s RV park the fan was running again, we checked in and I turned off the dash AC when we came out to unhook the Jeep, when I got to the rear of the coach the fan was slowing down significantly and you could no longer hear it working. Engine temp about 190*. I guess for me anyway, I will stick with the Danfoss fan controller, it confirmed to me that the fan needs to pull air thru the cooling stack other than when the engine has warm coolant.

JMO