A/C question

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May 24, 2010 | 10:02 PM

bren_tx

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A/C question

I just put in a brand new condenser in my truck (88). It actually is a condenser for a '95, as i wanted to get one from when they put 134a in from the factory. I flushed everything out real good, cleaned the evaperator (NASTY!!!) and replaced the accumulator and orifice tube.

I charged it up, it was just shy of 90 outside, and it was blowing about 47 from the vent. Im really exited about the results, Ive never gotten it to blow really cold since changing to 134. Now my question: the low side was reading 30-33 psi, but the high was reading 350-375! Im a new to the a/c world, and was wondering what would cause this and is it a safety concern

May 25, 2010 | 06:53 AM

subford

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From: Easton,Ks

No fan in front of the truck while working on it.

May 25, 2010 | 07:56 AM

rla2005

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From: Kentucky

I would still be concerned of the high pressures. Subford has a good point, it does indicate an airflow problem. Did you measure the temperature at the center vent with the A/C on Max, blower on high and windows closed?

Another question is the fan shroud in good condition? What about the fan clutch?

I just recharged our '97 Mustang GT 2 weeks ago. The pressures were 25/175 with center vent temperature of 34 degrees, outside temp. was 75, humidity at 85%.

What other changes did you have to make to adapt the '95 condenser to your hoses/fittings?

May 25, 2010 | 08:36 AM

hotrod351

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From: mohave valley, arizona

thats high for the high side. problem is you need to vacuum the system down before you charge it. by creating a vacuum you will pull most of the r134 in without it being under pressure. thats what i did on my 70 mustang conversion and its worked great here in arizona with outside temps in the 100,s +. you can get a cheap vacuum pump that connects to a air compressor that will do the job.

May 25, 2010 | 01:26 PM

MBDiagMan

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From: NE Texas

Yes, if you did not evacuate it, you need to have the charge recovered, evacuate and recharge. Also, check your fan clutch. A bad fan clutch will cause your high side pressure to escalate.

If everything is right, you should be able to get vent temps less than 40 with no trouble.

May 25, 2010 | 07:11 PM

bren_tx

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Quote:

Originally Posted by rla2005

you're right, i didnt have a fan in front while i was working on it. I measured it at the center vent with the a/c on max and the windows down. The fan shroud does not exist (broke into a million pieces when i crashed the front end) and i have no idea how the fan clutch is doing. It only makes a lot of noise at cold start up and then goes away. It probably should be replaced, its about 7 years old.

May 25, 2010 | 07:17 PM

bren_tx

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I tried to follow all the procedures by the book. I got a brand new set of gauges, got a vacuum pump. I pumped it out for about 10 min, then shut it off and checked to make sure it held for a while. Then i continued to evacuate it for close to an hour to make sure i got all the moisture out. When i came time to put the freon in, it sucked the first can out completely dry, and sucked atleast half of the second can before it had to start the engine. I finished that can, and hooked up a third can and only put about half of it in. I was aiming to get the low side where it needed to be and to get the vents blowing 40 degrees below ambient. I decided to stop adding freon once i got there even though i thought it should have taken a little more. I figured I could always go back and add more.