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Topic: Wax vs Electronic Radiator Fan Controller (Read 774 times) previous topic - next topic

Wax vs Electronic Radiator Fan Controller

I searched the Forum on the subject of fan controllers and found more information than I could possibly process.  My most basic question is, which type controller do I have?  (see photos below) 

Since I can see no wires going to the controller, I assume I have a wax controller.  However, reading the posts, mostly from two years ago, it sounds like electronic fan controllers were the standard OEM. 

Thanks,

Richard
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Wax vs Electronic Radiator Fan Controller

Reply #1 –
Your coach has wax, non-electronic high fan speed controller. Putting a ball valve on either of the hydraulic lines will force hydraulic radiator fans into high speed when ball valve is closed.

Re: Wax vs Electronic Radiator Fan Controller

Reply #2 –
Quote from: Barry & Cindy –
Your coach has wax, non-electronic high fan speed controller. Putting a ball valve on either of the hydraulic lines will force hydraulic radiator fans into high speed when ball valve is closed.
Rather than a ball ball use a needle valve. It is a very fine adjustment between fans not running and full speed. This is at the near closed position. There is a cap on the end of the valve and inside that cap is a Allen head that is uses to adjust your minimum low speed fan. This is basically a minimum for your INLET AIR TEMPERATURE. You need to have some unless you address separately. Also there is a special adapter required to prevent oil leaking during this adjustment. The set up you have is quite dependable in unloading your fans when cooler and ramping them up at higher temps. But is slow to catch up to needed requirements, probably why Foretravel switched to the electronic in later years. Temps are monitored threw ECM probably including engine,transmission and inlet temperatures.
Richard I believe 2000 was the transition year to the electronic controller.

Hydraulic fan controller DIY

Scott

Re: Wax vs Electronic Radiator Fan Controller

Reply #3 –
Please remember:

IDEAL is for coolant temperature to fluctuate some. If constant temp, you are wasting a lot of HP.

In that ideal world, fan speed from minimum (needed to keep intake manifold temperatures in correct range) to maximum would only occur several degrees after the thermostat is wide open.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Wax vs Electronic Radiator Fan Controller

Reply #4 –
FYI, we always drove with ball valve wide open, and only closed it for diagnostic and had it if needed for emergency use.

Never had problems with overheating once we learned to drive with part throttle, downshift, watching RPM, EGT, & boost. Coolant temps mostly 180, with some creep up to 185.

Re: Wax vs Electronic Radiator Fan Controller

Reply #5 –
Ive really learned a lot and am still surprised by new findings. I run my background fan speed very very low to basically make the fans rotate and nothing more till requested. I added a 100% shutoff solenoid and operate it during retarder use and brake use. Also has a automatic function for exceeding 150 degrees Inlet air temp. Typically fans have ramped up preventing hi IAT, due to engine loads exception being cold OAT downhills no retarder use transitions too hard climbs IAT will raise before temp bulb catches up. Rarely do I witness the fan automatically ramping up. Normal level ground engine, transmission, retarder temps in the 190 range. Hard pulls run up to 199. With fans commanded on everything drops to 170s. I like the idea of having manual control of the fan solenoid to cool down the coach prior to shutdown. All this can be delegated by running background speed were foretravel recommends but this come with the increased fuel costs running down the road with increased background speed all the time. No free ride. I am happy with the wax valve but feel the electronic would nearly do the same if the reliability was better. If you were to add the solenoid shut off valve to the electronic system that would be perfect. Improved fuel economy, cooler retarder, IAT management, increased dynamic braking, on command engine shut down cooling. Dependability and cost also figure in.
Scott