His post is very informative. It's just my opinion that the engineers who designed and tested the truck's clutch fan know more. Just like anything in life, there's different ways to accomplish the same results. If you feel that's the way you want to go, then go for it.
If I had the AC issues you are describing, I would do the research myself to see what options posters with similar problems are doing and choose the "fix" I like best. Fortunately I don't sit in traffic for extended periods of time and suffer pronounced degradation in my truck's air conditioning performance.
If I was concerned, I would probably start with a better than stock insulation and sound dampening material in the cab area. This would reduce heat transfer and quiet the overall sound levels decreasing driving fatigue. A win win situation.

 

The engineers who designed and tested the truck may have known more... but if so, they certainly delivered less than what they knew. I would like to think that they knew better than the cooling system they actually delivered.

Here is what they delivered:

• For the first three production years (1998-2000), Super Duty trucks with automatic transmissions, having GVWRs up to 19,000 lbs, and having GCWRS up to 26,000 lbs, shipped with NO oil to water transmission cooler in the radiator. ZERO. ZILCH. NADA.

Ford engineers "tested tough" the then brand new Super Duty, with no oil to water transmission cooler, but apparently, the wrong people were on that assignment, as they failed to understand the real world demands of towing.

Proof that Ford finally figured out their engineering error came with a production change to radiators with oil to water cooler in them, as well as a TSB advising service departments of the availability of parts to retrofit the previous three years of trucks with a new radiator and transmission cooling lines that have the oil to water radiator.

• For the first five years of production, the diesel Super Duty came with a 9 row oil to air transmission cooler that did not have enough surface area to dissipate the heat of the transmission fluid. The design of the cooler's passages were further prone to collecting debris, restricting flow, impeding cooling performance.

Proof that Ford finally figured out this engineering error came with a new oil to air cooler with 31 rows, and larger lines in and out of this cooler, along with the continuation of the oil to water cooler Ford added previously.

• For the first four years of production, Ford Super Dutys air conditioning system had to constantly overcome the full flow of hot coolant through the heater core, with no provision to redirect the coolant when the AC was on, or when an operator simply wanted a fresh air setting.

Again, proof that Ford's comfort and cooling engineers got this wrong came in 2002, when a vacuum valve that was previously introduced in the Excursion was expanded across all models of Super Duty, even the chassis cabs. This valve partially diverted the coolant flow from fully circulating in the heater core, making the AC more effective in the MAX setting.

The moral to these anecdotes is that engineers don't always get it right at first. And even if the engineers do get it right, their findings don't always end up in the production models we are able to buy. Perhaps accountants creep in at night and erase CAD files to cut costs. Who knows?

What I do know is the end result we are left with. And that sometimes includes problems that are up to us to solve, because the engineers didn't solve them in the first place, and/or their solutions were not made available to us. Further, Ford won't solve them retroactively out of warranty.

That's why questions like the OP's exist. Because despite all the degrees and the calculators and the sliderules, the engineers don't know more than we do about what it's like to be stuck with the results of their designs long term. If the AC was cold enough in the 99-02 Super Duty as originally delivered, then an after market vendor wouldn't have made a boatload of money over the last 16 years selling a solution to fix the problem.

Eventually, the engineers do get it right, as every year or so sees an improvement, or a production resolution to a problem, as illustrated in the points above. However, some of us can't afford to buy a new truck every 5 years, so we have to scrabble together our own solutions with what ever we can get a hold of.

 

I hear what you're saying, but we don't know what parameters they were required to stay within to meet a wide variety of conditions. We haven't even talked about how the bean counters possibly affected it.

 

Here you go. Sorry, been busy with work.https://www.ford-trucks.com/forums/1...hich-wire.html

 

The OP states in original post that he has a 1999 model year. The solution in the quoted link is for the 6.0L, which uses a different type of fan clutch.

The fan clutch in the 7.3L is not electronically controlled. It doesn't communicate with the PCM, nor is there any way to muck with wiring to make it engage full blast, because there is no wiring to muck with.

Many years ago, US Gear, before they went out of business, offered what they called a "Cyclone" fan clutch upgrade for 7.3L engines. This "Cyclone" clutch was a Vistronic type of clutch that was controllable electronically, similar to the factory fan clutch in the 6.0L.

US Gear's Cyclone was the only product I became aware of that offered in cab control of fan clutch engagement of the 7.3L engine... but it required the replacement of the OEM fan clutch, because the factory fan clutch in the 7.3L is a viscous clutch that is entirely independent of any external control. The OEM clutch engages and disengages based on it's own thermal coil on mounted on the clutch itself.

Even to test the factory fan clutch "maximum fan speed" rpm parameter requires bringing the minimum engine operating temperature up to 205 degrees F. In other words, the OEM fan clutch requires the ambient environment to be adjusted in order to test it... meaning there is no provision on this clutch to directly engage it manually or electronically.

 

Ah yes, I see that now. Guess I'm still too busy. Or maybe I didn't realize people were still driving those old things anymore





That's an inside joke for the rest of you 7.3 owners