ScarabChris

My AC blows super cold, as long as the car is moving. Obviously the condenser is not getting enough air flow when the car is sitting still. The fans come on with the A/C but not being fully shrouded I don't think they are puling the air through.

Once the car is moving the A/C blows super cold. Don't get me wrong, the A/C still blows cold when the car is idling, just not as cold and in the 100 degree Miami sun you can feel the difference when sitting in traffic after just a couple of minutes. It doesn't take much speed to get it super cold again, once the car hits 15 MPH it starts cooling as air gets sucked in from under the car.

So...what are your thoghts? I was thinking about adding a 3rd fan in the nose of the car that I can turn on with a switch from in the car just to blow some air on that condenser when in traffic then turn it off once moving again.

I would rather not have a "rig" and have a real solution.

Bob88GTA

iTrader: (2)

I wouldn't waste your time with a 3rd fan Chris. That's the way they operate. ANY cars AC system will do that sitting in traffic or in town. You just don't have the air flow that you would have a speeds. Pavement heat, car heat, everything effects it sitting still.

ScarabChris

Nope not all cars do that. I have owned about 30 vehicles of various makes and models over the years and this is not a common problem all vehicles have.

My daily driver is the Escalade in my sig pic. It has the 6.2 LS and I can sit for hours idling in the 100 degree heat and it will freeze me out. And in fact if you walk close to the front of the Escalade with the AC on your shirt will be sucked to the grill. That's how much air movement the fans provide.

The difference is the electric fans are fully shrouded and there is an actual grill in front of the condenser so the outside air is forced to be pulled through the grill, condenser and radiator. The TA has two electric fans just mounted close to the radiator but no shroud, just the rings that connect the blades which I'm sure helps....but not enough.

This might be a typical issue on the F body cars. I have had a few when I was younger but I don't remember this being a problem. It might have been, I just don't remember it.

Hell my first car was a 1978 Monte Carlo with a 305 and even that car blew ice cold air when idling for long periods. Fully shrouded belt driven fan and a massive grill to draw in outside air.

I'm sure I can remedy the problem I have, one electric fan in the nose blowing some air on the condenser......or a new fan and shroud assembly where the fans are fully shrouded to the radiator and no gaps between the radiator and condenser.

Bob88GTA

iTrader: (2)

Sounds like you got it figured out. Try it and let us all know how it works. Best of luck.

Drew

iTrader: (58)

R134a?

Cleaned out the condenser lately? Have you cleaned out the gap between the radiator and the condenser? Are the foam baffles still between the condenser and the rad support?

I've seen plenty of people blame the lack of fan shrouding for overheating issues, etc... But considering these were some of the first cars around with electric fans, you sure do see a lot of them rocking the original equipment. You would think that if the stock fans just simply weren't good enough that after 30 years there wouldn't be nearly as many still running around with the stock parts. Hmm...

Fast355

iTrader: (2)

I have converted 2 of these cars to LS1 F-car fans as well as a 1983 G-van to the same fans. All 3 of them have very cold a/c at idle. The F-cars were on R134a and the G-van is on R152a. My 2nd G-van build is on the way and it too will run the LS1 F-car fans to cool the 6.0L. I have yet to pay more than $50 for a used LS1 F-car fan setup in working condition.

Also I would highly recommend swapping the condenser for a newer style replacement. The stock tube & fin R12 condenser leaves a lot to be desired next to the newer parallel flow units.

1986_IROC-Z

It's a little bit of everything mentioned. The stock AC at idle in these cars isn't great for a lot of reasons...
...poorly insulated evap box, close to exhaust manifolds
...poor under-hood ventilation
...serpentine condenser on older F-cars. Much less efficient than parallel-flow
...a single cooling fan for rad and condenser before '89-ish or so.

I've been told replacing the condenser (if yours is not already parallel flow) as well as upgrading the cooling fans for larger high-speed units will work wonders for idle and lower speed AC.

Fast355

iTrader: (2)

I have also found that a Ford Red 0.057" orifice tube works wonders for idle cooling with R134a. You end up having to play with the refrigerant charge to keep the compressor from cycling as much. I do not go by charge weight with R134a. I simply charge the system until the return line out of the accumulator just starts to get cold. On a 105°F day I have gotten my Express vans dual evaporator a/c system with both fans on high and recirculate to cool at 40°F at idle and 34°F going down the road with R152a in a factory R134a system with the 0.057" orifice, insulated evaporator box, and an inline heater shut-off valve.

I should also mention as a disclaimer I do have a 25% underdrive crank pulley on it. My idle rpm with the cam is 200 rpm higher than stock though so it is turning the compressor and fan about the same speed as the stock setup at the stock 550 rpm idle. Also going down the road at 80 mph with 4.56s in place of the 3.42s the accessories are turning plenty of RPM as well.

My Black on Black 2011 Infiniti M56S charged with R152a on a 105°F day blows 40°F within about 2 minutes at idle on high fan speed and gets down to 30°F on the road before the temperature control circuit cycles the compressor off. Within about 5 miles of driving on the highway the automatic temperature control set to 60°F pulls the fan speed back to about 2/3. With a properly charged R134a system it would blow on high fan speed for 20 miles and would not blow colder than 55°F at idle and 40°F going down the road. It could eventually get down into the low 30s after an hour of driving on recirculate. The quicker temperature pull down is very noticeable with the R152a. The a/c control system reads the temperature thermister in the evaporator and does not turn on the blower motor until the evaporator starts to cool and then slowly ramps ip the fan speed as the evaporator cools. With R134a it took a solid 30 seconds for the fan speed to hit high. With R152a it is less tha 10 seconds. On the Infiniti a $3.99 can of R152a aka Canned air/Keyboard duster charged the car to capacity and dropped the high side pressure enough that the cooling fans I had previously dialed in to run 100% duty cycle at 220 psi run at 65% most of the time. Now the only time I see 100% fan duty cycle the engine is running hotter than 180°F.

The compressors on both the Express and the Infiniti run quieter with R152a and turning them on is much less noticeable HP draw in the power department. Running R134a they both rattled very noticeably on a hot day. The Express van has a 12 year old 80K mile $200 aftermarket replacement compressor and the Infiniti has its 110K mile factory compressor still on it. Considering we run a/c about 8 months a year they are both probably due for replacements and my testing is on well worn systems, fairly worse case scenarios. I am sure the cooling fans on the Infiniti are also not quite turning the same RPM they did when new either. 110K miles surely does a number on the motors brushes and shaft bearings/bushings.