Therotaryrocket85

Ive got an 88 vert that is bone stock and still running the freon setup. When i drive the car as speeds lets say 40 and above the air is ice cold and keeps the car plenty cold. However when i get into traffic and im at stop lights and such the air isnt as cold. Ive owned 2 fb's and they did the same thing, both had perfect freon levels and everything was 100% but this is my first fc so im wondering if this is a characteristic of these cars because its not turning enough rpm to sufficiently cycle the system or if i might need to have the freon level checked? I guess in a nutshell my question is are all of yalls the same way? Normally i wouldnt ask soemthing like this but my fb's were both like this so im just wondering if its a characteristic. Living in the armpit of texas with a black car gets hot! Thanks everyone

nyc_scorpio

iTrader: (1)

yeah man, mines does the same **** when i hit a stop. it must be the low RPM's that cause this.

homebrewer

A/C is nothing but a heat exchanger. The system is more efficient when driving because a greater amount of airflow is flowing thru the "coils". This is also aggravated by the fact that at idle your compressor is spinning slower than at normal driving speeds. It all adds up. I wouldn't worry about it.

slpin

iTrader: (9)

the e-fan on the front working?

waldo

This happens because there is not enough air flowing through the air con condensor (thingy in front of your radiator) because once the gas has gone through the compressor and cools the air down that gets blown through your vents, it comes back out very hot and needs to be cooled again, ie using the condensor so without this airflow the gas isnt being cooled enough and ur aircon isnt working that well, air con is pretty weird but amazing especially the aircon that can heat, it does everything backwards making the gas very hot anyway i hope this helps

cheers, todd

Therotaryrocket85

Ahh i c i c, so if i was to mount a small pusher fan on the thing in front of the radiator would that help the situation? Ive got one i could throw on there if thats the case.

slpin

iTrader: (9)

there should be a fan already.... at least on mine... check if yours work.

Therotaryrocket85

I just looked and all ive got is the factory fan clutch for the radiator. Theres nothing on the front of the evaporator.

slpin

iTrader: (9)

ah hmm... mine has one...
heh bolt one on and let it push, shouldnt hurt?????

jhammons01

What???????????

You guys need to get some schoolin'

The compressor "compresses" gas and it gets hot when its "compressed". The gas then goes to your an expansion chamber Inside your dash where the pressure is released and a cooling effect takes place as the pressure is released from the gas. This is what cools the vents inside the car, then you blower motor forces air throught this radiator type object and cool air comes out you vents. Then the compressor sucks the low pressure gas back in and the process starts all over. These terms are all distilled down for discussion sake.

While at idle your compressor is not able to compress the gas (R12 or 134a) at a very fast rate because the rpms are low, and therefore less gas is being compressed/released into the Cold head. Therefore the air from your blower isn't as cold.

Mine runs between 37° and 42° F while cruising on the freeway. But during a hot day just running errands around the immediate area, I might only see 52°F out of the vents......And yes I have a photography thermometer in the middle vents.

slpin

iTrader: (9)

you know that thingy infront of the radiator that cools that hot compressed gas?
what if its very hot and the effect of the lowering pressure is nto enough to overcome the very hot initial temperature?
dunno... stop the car, and wait till the ac doesnt blow cold, and then rev it and hold it at 3000rpm, see if it gets any colder....

JerryLH3

iTrader: (11)

If you're not already doing so, try pressing the button for recirculated air. Theoretically, that air is already cool, so it wouldn't be as hot as if the air was still drawing hotter outside air.

FCguy

One way or the other air must flow through the condenser to make the system work much at all (It WILL work without air moving through... just very poorly). Most newer cars with stock eletric fans will kick the fan on when the AC is turned on to move air through the condenser. So even if you rev the motor at a stop light you will only make the problem get a small bit better. The best idea so far was a small fan on the condenser. Also If you do an aftermarket e-fan setup you could slice into the AC clutch power line to kick on your fan relay to get the same effect as newer cars. Or do like I do... windows down at 100+

slpin

iTrader: (9)

those were my thoughts exactly...
however, the guy aboved me who claimed everyone needed schooling said it was due to the compressor speed, NOT airflow on the condensor...

thats why i asked him to hold the rpm up to speed up the compressor...

imo, the compressor can spin as fast as it wants... but if the condensor isnt doing its job...

Therotaryrocket85

Well i attempted the revving thing but that hardly made a difference. Back when i had my 84 gsl i converted over to an e-fan and was stupid and bought the cheapest one on ebay i could find. well i didnt even look at the size of the fan and i think its 8 or 9 inches hehe. Anyways i never used it so i guess this would be a good practice to try it out ehh........ Do yall know which wire it is on the compressor that i need to splice into? Id like it to come on when the compressors on. I think that would be a perfect setup.

slpin

iTrader: (9)

yup... it didnt make a difference because jhammons01 is full of **** about the compressor speed...

thats why some of the cars have a fan on the condensor itself...

put a fan infront of the condensor and push it... wire it so it turns on everytime the ac is on...

see if that helps.

slpin

iTrader: (9)

here - you can see the fan
look my car came with it...

jhammons01

Well, OK I'm not going to argue.

Note, Fans "pull" air over radiators/condensors.

The condensor is there becuase the compressed gas is very volatile and heats dramatically when compressed and Cools dramatically when expanded. That is why we use it. If the temp of the gas is cooler to begin with then it raches a cooler temp when expanded. We try to bring the temp of the gas down proir to it reaching the expansion chamber.

If you having problems, your problem lies with the gas inside the system. You may say it is charged but do you know for sure?? Who filled it and with what?? If you have had the system recharged with 134a then a recharge might be in order. 134 breaksdown over time which is why we switched from R12 which never breaks down and attacks the ozone. So even if you have 134a then a recharge may be your cure. A Purge and refill with new oil may be what you need. New E-Fans and gizmos aren't the cure for your ills.

Have you had the system checked for leaks??? You may fill it but in a couple of days it leaks down=won't work. Could the Carcoal canister be clogged?? If the gas cannot run throught the system then it cannot be compressed and the released=cooling. The canister is a filter system to capture impurities and oil. The oil returns via a return line but shavings continue to acumulate in the canister.

NOBODY has mentioned any of these issues with your cooling system. Yet some are said to be full of ****. Like I said earlier MY clean and running system cools between 37°-42° with no Ronco Gizmos OR rewiring my completly stock A/C

Now if you like we could pull out the Freon and replace it with Helium and cool things down to about 70 kelvin. That is what we do at our Cryogenics department. But I think if we did that to your car you wouldn't like driving a BLOCK OF ICE!

harley71105

Actually she should not warm up that much....you may want to remove your fan (reg fan on the water pump) and the shroud on the radiator. Then take a high pressure water hose and blow out the trash between the fins on you RADIATOR and your CONDESOR coil in front of the radiator. When I checked mine it was so full of bugs and leaves, etc not much air could flow through it. This will make it run cooler for sure and the AC will be somewhat cooler.

harley71105

Shhoooot.....I want some Helium in mine.....what kind of oil do you use with that....is the head pressure in spec with the compressor ? Helium is even cheaper than R134a

jhammons01

^^^I've been tempted. BUT, Too cold and it would just freeze up. When we cool things down to that temp ist is usually in a vacuum. We use this temp to acutally capture any residual molecules remaining in a chamber creating a higher vacuum. The molecules flowing in free mean path eventullay bounce the way of the Cold head Charcoal array, when it hits the array it 'sticks'.

That being said think about all the H2O molocules present. Think about condensation on a gallon of milk that is left out. Only the condensation freezes, forming a big block of ice. That is the problem, especially in Louisiana with all your humidity.

But all this technology is years old. It is a simple process of compressing and releasing the gas in a closed loop. That is why the A/C thing is frustrating. A/C is this black magic that nobody but the highest trained technician should be allowed to work with it..........that was sarcasm. Once you get the principle process of what is happening you can isolate your problem without attaching anything from Ronco OR ACME.

slpin

iTrader: (9)

dude jhammons....
jsut becuase you made up a page of stuff doesnt really mean you know what you are talking about...

how about this

turn the car at idle
let it run till the ac doesnt blwo cold
get a hose and keep spraying the condensor
so the condensor is cold, and doing its job on coolign the inside freon

get in the car and see if it blows cold

and it WILL


my point is, the condensor is NOT doing its job and thats what it is causing his problem

with water to cool the condesnro, you will see that it works even at idle speed, and the compressor does NOT need ot spin anyf aster.

RotaryEvolution

iTrader: (30)

it is not as complicated as it seems but since it is an unseen action most people simply do not understand how the system works. since i don't feel like typing it out i linked to a descriptive website:

http://www.familycar.com/Classroom/ac1.htm#ACCUMULATOR

yes, idle compressor speed will affect the cooling efficiency and yes with no airflow over the condenser the efficiency is also decreased and yes by turning on recirculate it will increase the efficiency of the system and yes the evaporator can freeze in humid or during other circumstancial times (plugged orifice tubes or other failures and sometimes normal conditions) causing the system to stall and blow warm.

so, you all are right in some ways...

slpin

iTrader: (9)

but karack.... the problem he is expereincing is no airflow to the condensor, way more than a comrpessor not being able to keep up.

my ac in the 87, has r134 in it, and i could idle all day and still have it blow cold... also hav ea fan

Therotaryrocket85

It runs on r 12 still and i had it checked when i bought it and it was at the correct level. Also when its running you dont see any bubble or extravigant motion in the little eye. I installed the fan and hooked it up on a relay with the aircompressor and it did make a difference. Its not quite as good as id prefer but its definately tolerable now. Before it was just miserable. My radiator and all was recently replaced before i bought it so everything is clean and fresh. the way i see it after doing some research in the haynes manual i see that from the factory mazda offered an electric fan for the condensor that came on at a certain temp but also came on when the ac compressor was kicked on. Mine didnt have this option so i put it in, and the difference is apparent. The system doesnt have any leaks and it hasnt gotten any worse sense i bought it, just stayed the same. Now that the fan is there its much better although id still like a small margin of improvement. I guess tinting my windows would help a ton too.

How much would it cost to convert her over to r134a? Ive always heard mixed emotions of switching over and heard that r12 cools better so i dont want to make it worse. Honestly after the difference i feel today im thinking if i get dark tinted windows that would make the difference im looking for...... it sure did on my 91 vette i used to have.