Fuso inadequate AC system fixed

kerry

Expedition Leader
I got inconsistent readings on the drive home so I don't have a definitive test of the modification yet. I think it will take a long hot day's drive to get the real answer as to whether the modification is effective. Michael, have you had any more experiences which confirm that your AC problem is solved?
 

kerry

Expedition Leader
My symptoms of cold air at low speed and warm air at high speeds might also be indicative of low flow over the condensor at high speeds. Has anyone considered this and maybe experimented with an air scoop around it to see if AC performance improved?
 

kerry

Expedition Leader
I carried out a similar vent air temp investigation on my 1994 80 Series Landcruiser today. The temperatures got colder the faster I drove. At 63mph it was putting out 22 degrees at the vents. I'm really curious as to what air vent temperatures people are seeing on their FGs at various speeds.
 

SkiFreak

Crazy Person
So Kerry... do you think that the valve you installed to bypass the cab heater has had any beneficial effect?
 

kerry

Expedition Leader
It's too early to tell. I need to go on a long drive on a hot day to know. I just read a thread on another forum where a guy claims that his condenser in a Mercedes 126 which had been converted to R134 was too small to re-liquify the refrigerant above 95 degrees. Below 95 degrees is worked ok but when ambient reached 95 degrees he gained 10 degrees of temperature at the AC vents. Our condensers are not huge. However an inadequate condenser would not account for my experience of inadequate cooling at highway speeds and adequate cooling around town at low speeds. Someone suggested to me that low refrigerant may exhibit these symptoms. I sure would like to know what temperatures other people are experiencing at varying speeds to know if my truck is an anomaly or not.
 

kerry

Expedition Leader
OK here's an update with some not so good news and some good news. We're driving east from Denver across Colorado and Kansas. Air temps just over 90 degrees. Coolant shut off valves made a slight difference. Maybe a degree or two cooler at the vents but still 60+ degrees at the vents at speed. Not cool. Stopped at a picnic site for lunch and let the truck idle. Vent temps in low 40's. Soon as we got back on the road, vent temps went up to mid-60's. So I was trying to imagine what might be causing the problems at speed if it wasn't hot coolant flowing thru the heater core. I speculated that maybe the condenser wasn't getting adequate air flow at speed. We stopped in St Francis for fuel and I looked at the condenser. Mine has a rubber flap that extends down in front of the condenser just behind the bumper. I suppose it's there to protect the condenser from road debris but I thought it might be disturbing the air flow at speed so I bent it up and tucked it behind the bumper and pulled out on the highway. Presto, problem solved. Vent temps now at 43-45 degrees at speed! In fact, it was freezing us out. Had to turn it down. I think what is happening is that the rubber flap bends backwards at speed and directs the air under the condensor so it doesn't work. At low speeds it hangs straighter and the fan can suck air up thru the condenser. Anyway, it looks like my problem is solved. I'm assuming that rubber flap is OE. If so, it's a stupid design. So if your AC is not cooling well at speed, get that rubber flap out of the way and see if it improves.
 

SkiFreak

Crazy Person
I'm thinking that a nice little picture that demonstrates the problem you have described/resolved would be good.
 

kerry

Expedition Leader
My camera batteries are dead:) In these pictures I had, you can see the flap hanging down under the front license plate.
 

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FG Surfari

Adventurer
To note, I removed the same rubber condenser surround on my FG when I fitted the larger tires to the truck a few months ago.
As such, you are correct in your find, as the AC in my rig is much colder now.
 

DontPanic42

Adventurer
Since the rubber flap appears to be for protecting the condenser from damage by rocks and other debris, how practical do you think replacing it with a mesh one similar to the wire screen around the transmission cooler? Sounds like a winter project for me.
 

kerry

Expedition Leader
My wife suggested mesh too. I'm not convinced the protection is really necessary. What do other think? I suspect mesh might even disturb the air flow into the condenser. I've got a standard transmission so I'm not sure what the transmission wire mesh looks like. I think swapping out the rubber for something else would be pretty easy. I think it's just pop riveted to the bracket.
 

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