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A/c diagnostics : Blowing semi-cold

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Old Jul 1, 2012 | 08:47 AM
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Default A/c diagnostics : Blowing semi-cold

Iv always had a/c problems with all of my sc's but if im going to keep this one, i need it ICE cold.

its a r134a system and holding pressure perfectly.
the ac never really cools down, and iv noticed on HOT days it over heats the car and the ac is luke warm.. maybe 5 degrees cooler then outside. i plan on replacing the T-stat, dryer and condenser first before i try the compressor.

any thoughts?
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Old Jul 1, 2012 | 09:03 AM
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Don't forget to replace those o-rings while your at it.

I always vacuum as much air out of the system (creating negative pressure) before filling it up with r134a. This will help remove any unintended air gap.
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Old Jul 1, 2012 | 09:07 AM
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Forgot to mention that I already did that at the beginning of the summer. All new orings on every connection. There were plenty of rock hard ones I found
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Old Jul 1, 2012 | 10:14 PM
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install a pusher fan on your condensor and change your drier.
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Old Jul 2, 2012 | 06:28 AM
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^ did that

https://www.clublexus.com/forums/per...condensor.html

ill try putting a new drier in first since there so inexpensive. then ill try a condenser if that doesnt change anything.. or possibly the pump
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Old Jul 8, 2012 | 09:31 AM
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I'm having a similar problem with my 300. The compressor comes on, the system is charged but no cold air. I did have heater control valve problems back in the winter. I had it bypassed for cold weather. I put a HCV I got out of the scrape yard on. Not sure if it's in proper working order or not. It never draws the rod up so I'm assuming something is wrong with it or the vacuum part. At this point I'm purely guessing that it's just all the hot coolant flowing through and that's why I get barely chilled aired through the system. I bought that Ford part that was suggested in a HCV topic that I'm going to try next.
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Old Jul 9, 2012 | 06:20 AM
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let me know. i think its something else for me, this morning i had pretty cold a/c.. however the ambient temperature was upper 70s and drizzling.
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Old Jul 9, 2012 | 05:19 PM
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Tried the Ford part that closes and keeps the coolant out. No real change in the temperature coming out. I dropped it off at a shop this morning and missed their call this afternoon. I recently replaced the valve cover gasket and went ahead and did the EGR delete. I might have missed a vacuum line in there or something. I'll know more tomorrow.
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Old Jul 9, 2012 | 10:17 PM
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sounds like you have a freon pressure prob. if the ac doesnt get cool/cold at all then there would be a prob. with your ac on try releasing air out of your system untill you see liquid/mist freon flying out. check your a/c again then add a bit of freon with the bottle flipped upside down when filling. get rid of the can before it gets sucked bone dry and the pressurized air gets into your a/c system. after pressure checks out with the a/c on rev your motor to about 3500 rpm to make sure the system is not overpressurizing and shutting down. the trick i use is to pull all the air out an run as much pure freon as possible bc those little air pockets in your system gets hot and itll force your a/c to run warm.

i would put the recommended oz of freon in + 6 more oz then start to purge air out to the ac system. the amount of freon i use is above the recommended amount and below the amount that would shut down the system from over pressurizing. i run this on all of my family cars and some customers that are willing to fork out the extra cash for 1 more can of freon.
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Old Jul 10, 2012 | 01:25 AM
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Its possible that it could be a bad expansion valve.
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Old Jul 10, 2012 | 09:36 AM
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yea, like it gets cold in the morning but i cant run it to long or my car over heats.. and it doesn't just mildly over heat, it starts climbing and doesn't stop.. i have no idea why that would happen besides the fact i put a pusher fan in front of the condenser to try to blow more air into my puller fans on the inside of the radiator. maybe at highway speeds its actually lowering the airflow.

idk
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Old Jul 10, 2012 | 09:58 AM
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how much r134a do you have in the system?
did you pull a vacuum on the system before you hooked up the refrigerant?
are you using the stock viscous radiator fan?
sooooo, so do you have an overheating problem, or an AC problem?

i'm not posting my most obvious question until you answer the questions above!
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Old Jul 10, 2012 | 10:18 AM
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I have both problems.

I may not have enough in the system to be honest, I used a large can of ac pro. I did have it on a vacuum and it held pressure as it should. I thought it was enough refrigerant because the compressor kicked on and the gauge was reading where it should.

I'm running an aftermarket aluminum supra radiator and two 15" electric puller fans that pull the air from the front of the car through the radiator toward the motor. I recently put on a 14" pusher fan in front of the condenser Blowing air into the two puller fans, and it seems like my over heating issue stayed the same when the ac is on.

Im thinking tstat, water pump or a bad heater core. The headgasket was replaced with a hks one three months ago when I did a head swap to a rebuit head. I had the system flushed at a local shop and they said they didn't pull out that much grime
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Old Jul 10, 2012 | 11:17 AM
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AC problem:
the gauge was reading where it should according to the gauge, or according to the FSM? our cars take a lot of refrigerant... did you use the hanger gauges and a vacuum pump? how much vacuum did it pull and how many ounces is the big can you mentioned?

overheating problem:
do you notice that the problem is worse when you're cruising on the interstate? you see where i'm headed here?


also, i bet the stock viscous fan pulls more air than your dual/triple e-fans... just a bet!

don't you have like 500whp? you still haven't posted the obvious answer i am looking for!

Last edited by cartmill; Jul 10, 2012 at 11:22 AM.
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Old Jul 10, 2012 | 11:22 AM
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I bet it would too, unfortunently I don't have the parts to convert back since the previous owner did it. I also don have a shroud on it. I have a 3" fmic that blocks Alot of airflow. I already know I'm suffocating the engine bay. But there are plenty of people in Florida in much hotter temps with more humidity that run the same set up. To me I feel like I have a failing water pump or a clogged radiator.

Also to note It over heats ONLY with ac on while at idle and highway. It doesn't over heat if I'm just sitting in traffic when it's 109 outside.

Last edited by bryan767; Jul 10, 2012 at 11:27 AM.
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