The Big Gap

[1972RedNeck]

Is this gap causing me a problem?









When I am running down the road my A/C vent temp is 34*. When stopped, the temp comes up to 45* with the motor a 2,000 RPM.at Idle, it is 50*.

How should I fix it?



I don't think this would be a good solution.

My shroud is off of a 2X4 pickup so I used 2 spacers to make the fan reach the shroud since my truck is a 4X4. Would a 4X4 shroud fit better?

[VA72C10]

I don't think it will make any difference in the temp of the air coming out the vent. The compressor is getting turned faster going down the road and air is being forced over the condenser and cooling off the air much better than at an idle. Even in modern vehicles the a/c doesn't cool nearly as well when you're sitting at idle compared to when driving.

[jaros44sr]

is it possible you have the wrong mounts for your radiator, maybe 4 core mounts on a 2 core rad....

[cdowns]

yes that large gap affects negativly how efficiently air is being pulled over your cooling coils by the fan blade

[71 super]

To go along with cdowns, the 4x4 shroud is considerably larger and will help both in a/c coil cooling as well as general engine cooling.

[VA72C10]

While I agree a larger and tighter fitting fan shroud will help with radiator and condenser efficiency....aren't his cooling numbers on par for a factory style a/c setup? And isn't the main issue at idle/stop the compressor speed and lack of air over the rad?

If he has no other cooling issues...I don't see how fixing/changing the fan shroud would make an appreciable difference in the temperature of the air coming out of his vents...

[68gmsee]

Wow! 34 degrees is darned near freezing. I've always kept mine in the mid 40's on my a/c vehicles.

Another thing to think about is the insulation of the cab itself. At highway speeds the wind is dissipating a lot of heat from around and under the cab. When you slow down or stop, the compressor slows and the inside air in the cab starts to warm up fairly quickly. The a/c can't cool it down as fast.

[1972RedNeck]

I have an old A/C book and it says to shoot for 35*.

The shroud is off a 3 core and my rad is a 4 core. Are they different?

[VA72C10]

Originally Posted by 1972RedNeck

I have an old A/C book and it says to shoot for 35*.

The shroud is off a 3 core and my rad is a 4 core. Are they different?

Yes, 4 core mounts and shrouds are different....also 2wd and 4wd are different on the shrouds. a 4wd shroud is HUGE

[1972RedNeck]

Brothers and LMC just list one for 4WD, 3 or 4 core not specified. Are 4WD 3 and 4 core shrouds the same?

Are Brothers or LMC's better quality?

Originally Posted by VA72C10

Yes, 4 core mounts and shrouds are different....also 2wd and 4wd are different on the shrouds. a 4wd shroud is HUGE

Don't they just stick farther away from the radiator? With the 2 spacers I am running my fan is inside the shroud, so won't the 2WD shroud work if I get a 4 core one?

Nobody specifies 3 or 4 core either. Is non A/C 3 core and W/ A/C 4 core?

[VA72C10]

Not sure if a 4wd shroud is the same whether it uses a 3 or 4 core rad. My assumption has always been that they are the same....

What I was saying is the upper and lower mounts to the rad support are different for 3 and 4 core rads.
On a 2wd bb that uses a 4 core rad it also has a different shroud compared to a truck with a small block and has a 2 or 3 core rad. Not sure if any non-big block trucks came with 4 core rads from the factory or not and if they did whether they would have used the bb style fan shroud or a standard 2wd shroud..

The 4wd shrouds have a much larger area to capture the fan (the round part is much deeper) so that to me is what you need to not only get rid of the gap but also to make sure the fan is well within the shroud properly for optimal cooling

But again, I don't expect you'll find much difference in all in the actual a/c output temperatures with a correct shroud vs what you're currently running. maybe a degree or two...but not similar temps compared to when you're at speed....

[69sixpackbee]

You still did'nt say what type of system. Which condenser? Which refrigerant? I can tell you that my 134A-converted factory Four Seasons system is very stable..even at idle but I did all of the necessary sizing and appropriate adjustments to the system and I still have the large gaps like you.

Bud

[68 IRON]

50* air on a 90* day sounds nice to me....I aint got no a/c. You a/c guys...somtimes I..!