Fuso inadequate AC system fixed

[biggoolies]

I wonder if the Aussies lack of complaints about the AC system is related to the differences in ductwork, controls and cabling in a left hand drive versus a right hand drive?

Nah, they would probably say that us in North America are a bunch of wimps or wallys. ;-)

[Michel Szulc Krzyzanowski]

Hose size.jpg

Valves 1.jpg

Valve 2.jpg

Valve 3.jpg

[dwh]

That's one way.

If it were done properly, they should have used a standard heater control valve. There are a million types of heater control valve - cable, vacuum and electrically activated.

http://www.google.com/search?q=heate...w=1366&bih=622


Normally, only one valve would be needed, but if the cold air is blowing across the heater core, then I suppose to get the coldest air, one would want to completely isolate the heater core. In that case, a bypass type would be best.

Here's a kit for an electrically actuated full bypass heater control valve:

http://www.classicchevy.com/chevy-by...1955-1972.html


Looks like Michel's truck got fitted with a couple of these:

[ame="http://www.amazon.com/Four-Seasons-84706-Shut-Valve/dp/B000CNJ66E"]Amazon.com: Four Seasons 84706 Shut Off Valve: Automotive[/ame]

[kerry]

Thanks for posting those pictures. I think I understand what they did but I'm puzzled by it. They cut the hoses installed a bypass loop, then put shut off valves on the heater side of the bypass. BUT, without a shut off valve in the bypass hose, even with the valves open, coolant can still flow thru the bypass and not thru the heater core. If I were to put in a system like that, I'd want to be able to close off the bypass loop.

[kerry]

Normally, only one valve would be needed, but if the cold air is blowing across the heater core, then I suppose to get the coldest air, one would want to completely isolate the heater core. In that case, a bypass type would be best.

Here's a kit for an electrically actuated full bypass heater control valve:

http://www.classicchevy.com/chevy-by...1955-1972.html

That's the perfect system. It's what I think I will install in mine.

Same valve, only cheaper:

http://www.streetrodhq.com/detail/15...LECTRONIC.html

Before I order this valve, does anyone have a guess as to whether it will fit the FG heater hoses?

I ordered one of those valves. I'll let you know what I think when it arrives. It will be a number of weeks before I have the chance to install it.

[dwh]

Before I order this valve, does anyone have a guess as to whether it will fit the FG heater hoses?

The link I found says it'll work with either 5/8" or 3/4" which probably means that the valve has 5/8" fittings. So even if the truck uses 3/4" hoses, they'll still slide on to the 5/8" fittings.

EDIT: Also, the link I posted has a link to an installation guide .pdf file, which shows that the kit comes with rubber sleeves so you can slide the 3/4" hoses over the 5/8" fittings.

Also, I suppose you could wire iit to the heater switch instead of using its own switch - then it would open whenever you turned on the heat.

EDIT AGAIN: Hrmm. Never mind that last bit. The switch that comes with the kit is a rheostat that controls how much flow the valve allows. Neat.

[mog]

So hating to have all Fuso(s) lump together as having bad AC, weak frames, etc, I decided to test my Fuso’s Heating and AC system.

2002 Fuso FG (61,000 miles) 2002 Ford F-250 V10 (54,000 miles)
Both vehicles were within 10 feet of each other during testing and were tested concurrently.
Tests were conducted with an analog probe type temp gauge and a digital IR temp gauge.
Both gauges were check for calibration prior to test against know temperatures (freeze and boiling points of water).
F250’s Heating/AC system fan flowed approximately twice the CFM of the Fuso’s at maximum fan settings.
The Fuso was designed as a commercial truck, the F-250 was (now) designed as a light truck AND passenger vehicle (comfort).
Both trucks have approximately the same square-inches of front windshield Fuso- 2088sq/in.......F250- 2030 sq/in
All temperatures are in Fahrenheit.
Ambient temperature 69 degrees F.
Altitude 280 Feet above sea level.
Both vehicles in shade.
(A)-analog gauge (IR)-IR gauge

Vent temperature with no fan, cold selected, AC off:.....Fuso-70 (A) 69.8 (IR) ---- F250-70 (A) 70.4 (IR)
Vent temperature with full fan, cold selected, AC off:....Fuso-70 (A) 69.2 (IR) ---- F250-65 (A) 64.8 (IR)
Vent temperature with full fan, full heat, AC off:...........Fuso-129 (A) 128.6 (IR) -- F250-141 (A) 140.6 (IR)
Vent temperature with no fan, after heat cycle:...........Fuso-70 (A) 69.8 (IR) ---- F250-70 (A) 70.2 (IR)
Vent temperature with no fan, cold selected, AC on:.....Fuso-36 (A) 36.4 (IR) ---- F250-32 (A) 32.4 (IR)
Vent temperature with full fan, cold selected, AC on:....Fuso-32 (A) 32.5 (IR) ---- F250-28 (A) 28.2 (IR)

Conclusion – No heat ‘bleed through’ on either vehicle from heater core when selected off, even after a heat cycle has been run and allowed to cool.
F-250 performs better in both heating and cooling by about a 10-20% percent. This would be expect do to its design as a ‘confortable’ truck with other features such as leather, carpet, entertainment systems etc. Some of this ‘performance’ comes from the much higher CFM of the F-250’s system fan.
Fuso in above test, far exceeds design specification called out for in the factory service manual

[kerry]

That's interesting. I wonder what is happening to cause others to be inadequate. I haven't put a thermometer to mine but I know when I put my hand to the vents it's not blowing as cold as my other vehicles and the cab never gets as cool as my Landcruiser or Sidekick. Driving west in the afternoons in the summer I am always sweating and I few times I've decided it was cooler to open the windows.

[mog]

That's interesting. I wonder what is happening to cause others to be inadequate.

I can't really comment on the whole how well does the AC work, since I haven’t done much in HOT weather. Yesterday’s test for me was to see if there way a problem with the heater/AC system design, as the OP had stated. With no ‘bleed’ of hot air on mine (wow, they got 1 right, too bad about the other 100,000+ trucks ) I don’t see a problem there.

I would think that some of the AC system not super cooling is the fact it is a commercial truck, less cushy, perhaps the position of the condenser in a horizontal position with less ram air effect (although great in hot weather that it is not dumping more hot air into the radiator like a normal system), less cab insulation, front of truck is more exposed to outside air temp being a cabover, etc).

While it has not been a issue for me, my intent down the road is to mount the aux. AC unit for the cabin on the roof of the cab (ducting the air to the cabin), to keep the overall height of the truck as low as possible, and to protect the aux AC unit. So I will be able to use the aux unit to cool the cab also if that every becomes an issue.

More on Fuso AC here:
http://expeditionportal.com/forum/sh...ad.php?t=55123

[kerry]

Haven't installed the electric coolant control valve I bought but I did have to drive the FG from my house to the storage yard yesterday and conducted an experiment. I put the AC on high upon starting it. Air was very cold on my hand. When the engine reached operating temperature I put my hand in front of the air again. Noticeably warmer, confirming the problem I think. Should have had a thermometer but I didn't.