Manual override switch for eng.fan - Diesel Forum

corvair · 05-01-2006, 06:48 PM

Has anyone done a manual override switch for the engine fan on a 2003 6.0???
To turn on the fan sooner when needed pulling hills.
Thanks for suggestions,

rickeg · 05-01-2006, 07:16 PM

I understand WHAT your saying, I'm just confused as to WHY you'd want to have the fan on before it's needed.

corvair · 05-01-2006, 10:22 PM

[ QUOTE ]
I understand WHAT your saying, I'm just confused as to WHY you'd want to have the fan on before it's needed.

[/ QUOTE ]

Would you consider 235 degrees (Calif Emissions) before fan comes on full speed, when 240 Degrees is considered overheating.
"I do"!!!!

superchargedpsd · 05-01-2006, 10:43 PM

Does your truck have an electric fan then? Do the 6.0's have an electric fan from factory?

Bullrack · 05-01-2006, 10:53 PM

Nope, but they're electronically activated.

AutoJim · 05-02-2006, 09:54 AM

The Visctronic fan drive is not an on-off device, but one that modulates engagement based on demand. It starts engaging (for coolant temperature) somewhere in the region of around 215F, give or take a few degrees, and the amount of engagement ramps up as coolant temperature increases. Full-on in the region of 230-235F sounds about right to me.

The idea is to provide enough airflow to meet the cooling requirements for the engine without giving more than is needed, which reduces parasitic loss and fan noise.

For short stretches, such as pulling very heavy up a hill in hot weather, you *may* see coolant temps go past 240F, but they'll come down again quickly after you crest the hill. That's normal. It's expected. It happens. With a 16psi cap, the boiling point of 50/50 EG/W coolant is 264F, so there's still plenty of margin -- particularly when you consider that the pressure in the cylinder head water jackets may be 5-10 psi more, and you gain 3F in boiling point for each psi of pressure increase.

EGR cooling is the wild card on these engines. It may well be that, depending on where your aftermarket temp sender is located, that the readings you're getting are unduly influenced by the EGR cooler's heat output. The ECT used by the engine controller is located next to the thermostat bowl, which is a place that provides a thoroughly mixed flow of output from each cylinder bank and the oil cooler/EGR cooler circuit. If your gauge sender is in the heater supply tube (the location I've recommended, I know), you might be seeing 5-10F higher readings there than where the ECT is located, because the heater supply flow has a higher percentage of EGR cooler output as a contributor.

In any case, it sounds to this cooling system engineer like your system is working as it's supposed to work, and you probably don't need to do anything. Keep in mind that while you can jumper the fan drive for a manual "on" switch, it will probably set a code in the PCM when the fan speed signal goes outside the acceptable difference range from the commanded fan speed.

Jerryc · 05-02-2006, 03:09 PM

I never cease to be amazed at the number of people that think they can control their truck/transmission better than the computer can.

JC

SAVAGESAM · 05-02-2006, 03:24 PM

What if you wanted to do this mod. to improve your A/C at idle? Say like while you run into the local mom and pop shop. How would you do this mod.?

Black05 · 05-02-2006, 03:26 PM

Better to do the SEIC mod -- just idle the truck up to increase cooling efficiency. Double benefit of high idle when needed for battery recharge, PTO usage, extended idle, etc.

corvair · 05-02-2006, 05:18 PM

Thanks for the info,
I`m using the Edge plat. with gauges which I guess it is reading off the computer.
The temps just bother me,KW&Peterbuilt have a manual override switch in their trucks which make it more pleasant when pulling grades.

corvair · 05-02-2006, 05:24 PM

[ QUOTE ]
I never cease to be amazed at the number of people that think they can control their truck/transmission better than the computer can.

JC

[/ QUOTE ]

What do you mean "think" with the products that are out there most of them does a better job, especially with changing the shifting which is far better compaired to Fords program.

AutoJim · 05-03-2006, 10:08 AM

[ QUOTE ]
What if you wanted to do this mod. to improve your A/C at idle? Say like while you run into the local mom and pop shop. How would you do this mod.?

[/ QUOTE ]

Well, since the "AC on" is one of the things that will engage the fan drive, if vehicle speed is below around 45 mph, I'd say that it's a waste of time to rig up a manual switch to do something the ECU is already commanding.

AutoJim · 05-03-2006, 10:15 AM

[ QUOTE ]
Thanks for the info,
I`m using the Edge plat. with gauges which I guess it is reading off the computer.
The temps just bother me,KW&Peterbuilt have a manual override switch in their trucks which make it more pleasant when pulling grades.

[/ QUOTE ]

Big trucks use pneumatic on/off fan drives, so you really notice it when they hit, and yeah, it's an all-or-nothing kind of arrangement, so having a provision to manually engage it in anticipation of high load operation makes some sense in that case.

The main thing to keep in mind with the Visctronic is that one of its main advantages over an on/off fan drive is the ability to modulate engagement -- provide what's needed without excess noise or parasitic loss. It's tracking coolant temp, AC demand, CAC performance, and, on automatic trans-equipped trucks, trans temp, and following the logic involved. I know the guys who programmed and calibrated it, and they're really good cooling guys, know their stuff quite well.

What I would be concerned with in an aftermarket chip or programmer situation is that the aftermarket unit altered either the signal input into the ECU (which is how many "trick" the ECU to use different parts of the fuel/timing maps) critical to Visctronic operation, or altered the calibration for the Visctronic itself.

(edited to correct a typo, no content changes)

AllOutFirefighter13 · 05-03-2006, 11:38 AM

[ QUOTE ]
What I would be concerned with in an aftermarket chip or programmer situation is that the aftermarket unit altered either the signal input into the ECU (which is how many "trick" the ECU to use different parts of the fuel/timing maps) critical to Visctronic operation, or altered the calibration for the Visctronic itself.

[/ QUOTE ]

AutoJim,

Can you elaborate a little about this? Would an aftermarket chip/programmer alter the information for the fan, and if so, what benefit to them would it do? I'm not being sarcastic...I'm just interested.

Thanks,

Joey

6SPDMANUAL · 05-03-2006, 12:02 PM

[ QUOTE ]
I never cease to be amazed at the number of people that think they can control their truck/transmission better than the computer can.

JC

[/ QUOTE ]

WHY??
can't you drive better than your computer? my POS KR, crap-a-matic truck will not pull my trailer in OD with the cruise on,..why? because the computer "presses" the accelerator too much causing the tranny to downshift, cuasing the rpms to go up to nealry 3000 and then causing the temp gauge to rise to 80 and even 90% plus of the gauge. (sorry i do not have any special gadgetts to tell me the actual temps) anyway, when i drive, i can tow at 70, 75 or 80, which ever i prefer, and not downshift the tranny, not raise the rpms, and not raise the temp. so i think that many people are smarter than the computer and this idea (for some) is extremely valid. last year in south dakota, this would have helped me a lot, because the fan did not come on until the engine was hot, and each hill, it would get hot, so if you know a head of time and can turn it on, it owuld keeep it from heating up, because soon as it came on, mine cooled down.