The Auto Cool Guy has a better way to control engine temperature.
We use Pulse Width Modulation of your fan to control its RPM. Our sensor monitors the radiator outflow temp and adjusts the fan RPM to keep the outflow at a constant 15 to 20 degrees BELOW the thermostat temp. This way, the thermostat can regulate engine temperature. Use a laser temp gun and put the red dot on the outflow area and on a black dull surface for good results as you adjust the BLACK knob. Avoid shinny chrome surface due to temp errors. Take your time and do not rush this setting. After you have made this adjustment, you should see ROCK SOLID engine temperature. You will notice speed and motor load will effect your fan RPM - see its working.
By the way, fans with Auto Cool controllers do not KICK ON and off, leave that to the brand X controllers. Please don't tell me your Auto Cool wont KICK on.
FEATURES AND CONTROLS:
Soft Start limits inrush current with pulse width when the controller is powered up. Inrush current is a brand X controller killer when starting a fan motor from a dead stop.
A/C FAN SPEED control has a small pot on the side of the controller. When 12 volts is applied to the A/C controller pin, use a small flat blade screw driver to set this fan speed. The radiator temperature control mode will over ride the A/C fan speed automatically. If not used not a problem.
FAIL SAFE: The fail safe mode turns the fan on full RPM. The FS mode is turned on by grounding the FS pin. Use a small switch from FS to ground. You can turn FS mode on or off any time.
COOL DOWN TIMER: When you turn off the IGNIITION, the fan will keep running for a period of time to cool down your radiator and then shuts down.
FAN BUZZ: The buzz is caused by the fan blade and the armature shaft not tight.
We have found the Mark VIII fan have been reported at no buzz fans.
Our HF-125 controller runs at 7Khz to prevent the buzz but may have a high frequency tone cured by a large filter cap you see below. If your fan is brushless, use our HF controller only. The fan will vibrate at low RPM with low frequency controllers.
START ENGINE: As the motor and radiator is getting warm to hot, the fan will start turning slowly and gain RPM as the temp rises. The RPM will hold at the point of regulation set by the black knob.
We have a new Auto Cool customer in Santiago, Chile! He is putting the Auto HF-125 controllers in his fleet of trucks. Photo to the left is their snow covered mountains.
The Auto Cool Guy now has these special capacitors to cure the high frequency 7,000 Hz tone in you fan. One each is included with the purchase of the HF-125 controller.
If you have dual fans, may want to order a second filter capacitor.
DIESEL RADIATOR TEMPERATURE CONTROL
One of our early customers made this Youtube on the HF-125. At first we had a Fail Safe issue but corrected it and any that had been sold. This 7 Khz controller is one of our fastest selling controllers. Video made 2-2021
Sensor Warning: If your radiator OUTFLOW port is plastic, do not use the Standard Brass sensor. It will not get true heat transferred to the sensor! This will result in very low or no fan RPM.
I made this video of the DX-150 - how it works on the bench. It has ten LEDS that show percent of pulse width modulation = controlling radiator temperature.
US ARMY ORDINANCE:
CALLED UP FOR A TOUR IN SOUTH EAST ASIA AND ASSIGNED TO THE 295TH ORD. FROM HASTINGS & GRAND ISLAND, NEBRASKA 10-68 TO 10-69. MOS: SHIT BURNER AND AMMO SUPPLY LABOR. TOUR WAS IN CHU LIE, QUAN TRI CITY AND DA NANG.
The photo on the upper left is the Auto Cool Guy. Location was north of Quan Tri City just south of the DMZ. When we were out of our base camp we always carried our M16s and at least 8 clips of .223 ammo with 20 rounds in each clip.
The bottom left photo is the Auto Cool Guy and my pal Jim Stulken joy riding around in Chinooks - stealing rice from Charlie and giving it to local villages. One flight we filled up three CH47s full of bags of rice and hauled it out of the area.
During my time in Chu Lie I found an Army photo lab to develop black and white film and make 8 - 10 prints for some of the guys in the unit. Our CO called me into his office and ask me about making money on MY TIME. I ask if I was breaking any Army regulation. He said NO, and the issue dissolved into thin air. They even published some of my B-W photos in the 295th year book.
It may sound odd, by my time in Vietnam was very boring - always looking for the
next adventure. Stay tuned to this site for more Vietnam photos and stories that will change each week.