Fuso inadequate AC system fixed

[Bajaroad]

I drove through +95F temps last weekend and would argue the AC system on my '07 could also stand some improving. The rig was overheating climbing up the Grapevine (north bound) with the AC on, but that's another issue. I noticed that the air coming through the vents with the AC off was noticeable warmer than the outside ambient and that using Recirculate vs fresh kept the air cooler.
Although the windshield and windows are not much larger than a standard truck, the amount of light coming in the cab seems much greater, and your body is more exposed through the windshield. I'm hoping to find some type of shade for inside or adjustable visor for outside to reduce the direct light. Has anyone done this?

 

[bptp7270]

Hi Bajaroad,
If it is of any use there is a company in NZ called Airplex that make a poly external sun visor that would cut down on some of the direct sunlight through the windscreen. Their web is www.airplex.com

 

[kerry]

I put film on all my windows including a 6" or 8" strip across the top of the windshield. It does make a significant difference. I bought the film at O'Reilly's Auto Parts. Cost about $50. I still haven't had a chance to install the heater core shut off valve.

Mine started overheating climbing up to the Eisehower Tunnel last fall with the AC on also.

 

[Engineer Guy]

Keeping Your Cool

Some general observations that I hope help folks, even though from a long time Mitsi SUV Owner...

Due to dissatisfaction with my Montero Sport A/C, I wrapped the Coolant Tubing in black Pipe Insulation of the proper size. I wrapped it in Aluminum Foil. Aluminum Foil reflects some heat, too. To continue to have nothing flammable, I used thin Wire as Cable Ties to keep everything in place; not plastic Ties. Insulation 101 suggests that Coolant not losing heat as much will get to the Fan Core at a lower temperature. I don't have Test Specs to offer, but there was some improvement.

On my 3.5 L, the Coolant Tubing run takes a 90 degree turn at the Firewall and remains in the hot Engine compartment over this longer run over to the Passenger side. On my Neighbor's 3.0 L, the Coolant Tubing goes through the Firewall on the Driver's side straight away. Not surprisingly, due to only this variable, her Montero Sport A/C CRANKS compared with mine. Nothing to be done about this Coolant run path on mine, unfortunately.

This same idea of insulating Coolant Tubing runs is standard practice on Home A/C.

 

[KMTC]

Just so all of you know, This is not an approved repair by FUSO. This was a temp. fix by people at a dealer that just began selling these trucks that lack the proper training of the brand. There never was nor is there currently any service bullitins or recalls related to the a/c system on these trucks. Further more the a/c system is exactly the same on all FUSO FE and FG from 2005 - 2009. What you have been reading is a misrepresentation from people that have made repairs unauthorized by FUSO. The issue this truck had at the time was filters completely clogged and never being cleaned. You all must remember this truck in question sat by the beach all the time and as such would collect high amounts of sand in the cab. Thus in tern clogging the filter more than what we would all consider normal conditions. In such a case maintenance of the a/c filter would require more frequent cleaning. Could we have installed shut off switches to make it colder? Yes! Did the customer want his factory truck modified to be a pain in the *** everytime he wanted to run the heat? At the time NO.

 

[gait]

silly question .....

where is, and how to remove for cleaning, the aircon filter on my Canter?

 

[kerry]

On my US model it's in the ductwork on the passenger side. Drop the lower panel on the dash and slide it out. I've read a lot on here about them getting dirty and causing problems. I've never found dirt in mine.

 

[gait]

thanks Kerry, all clean now, a bit dusty. Insulating the coolant pipes makes sense to me, at least it had a significant effect on the efficiency of my fridge.

 

[gait]

air flow today in 34 degree C ambient temperature much improved, as is cab noticeably more comfortable. The filter wasn't blocked, just a tad dusty. Aircon still isn't world's best but every little helps.

 

[DontPanic42]

I use a 12 V fan to improve air circulation in the cab and it helps. I do need to check the air filters as it has been so dry and windy here for so long that there is dust everywhere and on and in everything.

 

[Deleted member 9101]

Its no different that on Class eight trucks. Under the hood you have a valve you shut off to block coolant from hitting the heater core. If you don't your A/C will not cool the truck.

 

[kerry]

posted this in it's own thread but I thought I'd add it here because the data is important. I'm guessing MOG did not test his AC vent temperatures at varying speeds. I don't know for sure what FUSO USA is officially saying but according to my data, there is a problem and it sure seems to me it is caused by lack of a coolant shut off valve to the heater core.

After Michael's post last year explaining the FUSO A/C problems being caused by not having a coolant flow shut off valve, I bought an electric shut off valve to install on my truck. However, I haven't gotten around to it yet. So, this weekend we headed out on a road trip and I took my non-contact thermometer because I was curious about tire temp. However as I was driving I realized I could get some real world data on the AC air temp at the vents since it was hot. Temps were in the mid-90's. On the interstate, driving 63mph, early in the day on the flat with no wind, vent temp was 66 degrees. Later in the day when it was hotter, we were driving into a headwind on long hills, vent temps got as high as 73 degrees. But here is the amazing part. When we pulled off the interstate and began driving around a small town looking for a restaurant, vent temps dropped quickly to 46 degrees and even as low as 42 degrees. On time when driving slow around town it got down to 39 degrees. I think this data verifies Michaels's analysis. Once the coolant flow increases at high rpm's the heat in the heater core is sucking the cold out of the AC system to a large degree. This also explains the impression I've had of my A/C system since I got the truck. Sometimes it works fine and other times it seems to loose its oomph. I think it all has to do with coolant flow. For instance, at 40mph in 5th gear, it can hold 58 degrees at the vents. I can't imagine anything else which would explain these huge variations in output air temperature. I will be installing the electric shut off valve in the near future so I'll be able to provide 'after' temperature readings.

By the way, my A/C on/off switch quit working. It will only turn off if I physically push it down in the 'off' position. I'll have to replace it. Can anyone confirm that the dash does not need to be removed to replace the switch but that I can pull the switch out of the hole its in? The manual appears to indicate this can be done but it's not entirely clear.

 

[kerry]

Installation of electric coolant flow control valve

Completed the installation of the electric coolant flow control valve mentioned earlier in the thread. Installation was easy as you can see from the pictures. 2 hr job max including coffee breaks. Haven't driven it yet to test the improvements to the AC but I can hear the valve operating. Hoses fit the 5/8" fittings on the valve.

 

[kerry]

Some of those pictures might be hard to interpret. The valve is right behind the front grill. I just cut the hoses and fit it in place. Lost about a quart of coolant. Wiring passes through a grommet in the left inside corner of the cab behind the headlights. Cut the grommet to slide the wire in place and then reinstall it. Switch is mounted in the left corner panel of the dash to the left of the transfer case lever. Picked up power from a wire I'd already installed to operate a solenoid in the 12 volt feed to the camper.

 

[kerry]

Drove it about 13 miles on the freeway at 62mph uphill at 90 degrees ambient temperature. Vent temps varied between 48-51 degrees. Looks like the problem is resolved. It's not a definitive test since it was a pretty short drive and I didn't turn on the flow to the heater to see if it brought temperatures up. But it's a pretty good indication the problem is the flow thru the heater core. I did test the new valve after the drive and it does control the flow thru the heater core with no heat when the valve is off. My drive home will be downhill so it won't be a good test but I can turn on the flow and see if the vent temperatures rise.