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tmw188 · 01-20-2023, 03:52 AM

So school me here on these fans. I have a side radiator Monaco. So looking at the photos is the Wax Valve a name branded upgrade to what I’m assuming to the Souer Danfoss? Is the SD OEM?

RV Driver · 01-20-2023, 08:04 AM

The Source Engineering wax valve is a replacement for the trouble-prone Sauer-Danfoss electronic system. I have the Thermal (wax) Valve on our Mandalay.

The system uses a wax-filled chamber to open and close a hydraulic valve. At 188 degrees the wax melts and the valve closes, causing the fan to run on high speed. When the temp drops below 188, the wax solidifies and opens the valve, slowing the fan. It’s a very simple and reliable system.

It’s not OEM, it’s a change/upgrade.

tmw188 · 02-14-2023, 01:58 PM

Quote:

Originally Posted by RV Driver

The Source Engineering wax valve is a replacement for the trouble-prone Sauer-Danfoss electronic system. I have the Thermal (wax) Valve on our Mandalay.

The system uses a wax-filled chamber to open and close a hydraulic valve. At 188 degrees the wax melts and the valve closes, causing the fan to run on high speed. When the temp drops below 188, the wax solidifies and opens the valve, slowing the fan. It’s a very simple and reliable system.

It’s not OEM, it’s a change/upgrade.

Thanks for that explanation, I didn’t noticed you had replied for some reason. Mine looks like the pic 3 in post# 1. That’s the fan motor is it the part on bottom that controls it?

RV Driver · 02-15-2023, 07:24 AM

Image 3 in post 1 is the hydraulic fan motor and the hydraulic lines to it. The small box under the motor is the valve that is operated by an electric signal to change the fan speed.

Image 2 is the Source Engineering Thermal Valve. That valve is installed in the hydraulic line to the fan. It then controls the fan speed by temperature alone. The Thermal Valve operates at 188 to 190 degrees to change the fan speed. The electric valve on the motor is either set to stay open by removing the electrical plug, or in some coaches (Freightliner’s) it is replaced with a cavity plug.

I’ve had this conversion on our Mandalay for several years now. Very pleased with it. The Source Engineering guys (Scott and Jim) are both good guys who know a LOT about these engine cooling systems.

tmw188 · 02-15-2023, 11:29 AM

Thanks RV Driver that’s kind of what I thought it was. Do some change this just as a improvement not know if their OE setup is an issue? Does it require any bleeding of the lines? I suppose it monitors ambient temp?

RV Driver · 02-16-2023, 07:26 AM

The Sauer-Danfoss electronic fan control that is original equipment in these coaches are troublesome and unreliable. I had a lot of trouble with mine. If/when the system failed, the “fail safe” mode was supposed to run the fan on high speed all the time, thus making sure the engine did not overheat. However, running on high speed all the time cost about 1/2 mpg, made a lot of noise, and raised tremendous dust clouds when entering an RV park with dirt roads.

However, that failure mode didn’t always work and I ended up with a fan stuck on the low speed range. With the fan on low speed, the engine would overheat on grades. That’s why I replaced mine with the Source Engineering Thermal (wax) valve.

When the Thermal Valve is installed, no bleeding of the hydraulic lines is needed. Any air in the system is quickly evacuated when the engine is started. There is a constant flow of hydraulic fluid in the system because it is the power steering pump that actually generates the pressure.

The Thermal Valve valve monitors the temperature of the engine coolant, not the outdoor ambient temperature. When it senses a temperature increase, at 188-190 degrees the wax melts in the valve, this opening the valve and changing the fan speed. Stone simple and very reliable.

tmw188 · 02-16-2023, 11:27 AM

That’s great thank you for answering those questions, it gives me a better understanding of the system controller.
I have a couple more questions on this. Is there a preferred location for these, just above the t stat in the elbow?? Are there different manufacturers of these wax valves?
How do I know if my fan is underperforming other than perhaps high coolant temps for no particular reason, or running wide open?
🤷

RV Driver · 02-17-2023, 10:35 AM

The wax valve is typically installed on the cross-pipe at the top of the engine bay. A hole must be cut into this pipe and the installation flange welded in.

The only company I know that supplies these valves is Source Engineering out in Oregon.

With the fan speed controller set to the high speed mode, the fan speeds should be:

Engine at 800 RPM Idle - Fan at 565 RPM
Engine at 1,400 RPM - Fan at 1,340 RPM
Engine at 2,100 RPM - Fan at 2,030 RPM
ENGINE at WOT 2,380 RPM - Fan at 2,000 RPM

These numbers are for the Cummins ISL engine, but regardless of which engine you have, the fan speeds should be close to these.

With the Sauer-Danfoss controller, you can set the fan to high speed by unplugging the small electrical plug on the fan motor control valve. It's mounted on the motor.

tmw188 · 02-18-2023, 05:41 AM

Great info, I’m unaware of any issues with my fan controller but I like this as a future upgrade. Are the OE controllers known for reliability issues? That install location seems to be about the best location and I would assume the hoses in the kit are long enough to work.

Mainecoons · 02-18-2023, 05:55 AM

If the wax controller operates on coolant temperature only I don't see how it would solve the problem of the fan running on high all the time regardless of engine RPM. One would normally be entering a campground coming off the road with the engine at full operating temperature. Hence I would expect the fan to be running pretty fast if only controlled by temperature. What am I missing here?

tmw188 · 02-18-2023, 06:00 PM

Reading back thru some of these posts it seems like it’s a little non specific on whether some need the orifice or not. How do you clock the rpm of the fan even if you know the correct rpm?

shootist · 02-18-2023, 06:12 PM

Quote:

Originally Posted by Mainecoons

If the wax controller operates on coolant temperature only I don't see how it would solve the problem of the fan running on high all the time regardless of engine RPM. One would normally be entering a campground coming off the road with the engine at full operating temperature. Hence I would expect the fan to be running pretty fast if only controlled by temperature. What am I missing here?

Diesel engines cool immediately when you back off the throttle. They produce so much heat under load that they are way over radiatored for idling around.

RV Driver · 02-18-2023, 06:31 PM

Quote:

Originally Posted by Mainecoons

If the wax controller operates on coolant temperature only I don't see how it would solve the problem of the fan running on high all the time regardless of engine RPM…

The Sauer-Danfoss controller also operates on coolant temperature. What else would it operate on?

The only time your engine would be at a temperature where the fan would run on high speed is climbing a long grade. Even if the RV park was at the top of the hill, by the time you get off the interstate and ease into the RV park, the engine has already cooled back to a “low fan speed” temperature.

gsander1 · 02-18-2023, 08:04 PM

The Sauer Danfoss operates on three parameters. Coolant temperature. Charge air temperature. Air conditioner compressor head pressure. This is particularly important to Magna and Affinity owners with the front and rear A/C evaporators. On a warm day the head pressure can build fast on startup. Without fan cooling bad things can happen.