Hello,

I replaced my high pressure line which sprung a leak on my wife's R52 Cooper. Added 1 oz PAG 46 oil into the replacement line, installed it, and vacuumed the system. Confirmed no other leakage as it held vacuum for over an hour. Added freon thru manifold yellow service hose. Now high pressure side seams high.

Here is what happened when gauged yesterday, the AC set max and car idled for over 10 minutes:

https://www.youtube.com/watch?v=7Ohs...ature=youtu.be

The low side rises to 40 psi & high side to 275 psi. Fan kicks on, pressures drops back down to low 35 psi, high 220 psi. Fan kicks off at this point. Immediately after, pressures rise to same numbers again (40/275). Fan kicks on again pressures drop then rise. Everything repeats, same numbers. Ambient temp was around 75f.

AC blows cold but only about 20 degrees less than outdoor temp. Also the low pressure line is not too cold at service port.

Any idea what is causing this?

Shouldn't fan run more constant?

Did some research... One possibility air in system. I had to use 2 cans freon. 1- 12oz can and approx. 2.5 oz from the second can. Could I have introduced air while changing cans. I had low side valve closed when switching. High was never open. Can tap may have allowed air into service line only?

Or... faulty expansion valve, receiver drier (did not replace original because mechanic who diagnosed leak said wasn't necessary)?

I was listening inside car under driver side dash with ear against blower assembly/evaporator and heard a slight hiss which increased to a bigger hiss as the fan would kick on (pressure dropping). This went back n forth as fan kicked on & off.
Is it safe to say the expansion valve is functioning properly?

Please help...

Thank you,

Shawn​

 

Did you replace the drier?

 

No I did not replace the drier because the mechanic who diagnosed leak said it wasn't necessary. I am kind of kick myself in the a** for not doing it because I had heard before that you should replace it when you open the system. I told him this and he said the line is only being replaced and system won't be open too long.

I did notice when feeling around the components that the drier is super hot. Not sure if that is normal or not.

Drier appears original. Probably gunked up and creating restriction?

 

It's probably saturated with moisture. Evac the system, replace the dryer, pull a vacuum on the system to remove the rest of the moisture, and then recharge the system by weight of refrigerant as per the manual.


Or take it to a qualified mechanic.

 

When I replaced the line I vacuumed it for about an hour. I didn't feel good about not replacing it then and there. It's my wives car and we're in South Florida so we are already in "AC Mode". LOL

Drier is on the way. Gonna pull another evac the system, put in new drier and vacuum the system again. And... replace my failed low fan resistor!

Thank you for your feedback

 

When you put in the first can to the yellow hose, did you open the yellow hose at the dials to let the can push the air out and let a little R134 escape? If not you may have introduced air into the system. Drier is my second choice. I am getting ready to do the same. My condenser went bad and have a used condenser I am replacing it with and will be going through the same as you.

 

The system was in vacuum so I didn't think I had to purge the line with the first can. I closed the high & low side valves on the gauge then turned off the vacuum. Then I unscrewed the yellow line from the vacuum port and screwed the line onto the can tap (which was closed & already screwed to refrigerant can). I didn't think air could enter this way. Was I wrong in doing this?

 

there are 2 verdicts. Even though it is vacuumed, it is still air. Here is the link that I followed which states to pressureize the line with R134....

http://www.wikihow.com/Recharge-the-...ioner-in-a-Car

Step#6

 

From what I read in the article, they purge the line and then determine whether or not you need refrigerant once the charge hose is connected to the system. In my case they system was empty and in suction/vacuum. All air & moisture should have been removed.

Either way I'm gonna replace my drier, do another vacuum and recharge. When I do I will play it safe and purge both lines. First the yellow "service line", then the blue charging line. I read you must purge the yellow first, then the blue.

Another option is to get a can with the charging line connected. No need to purge, just connect and fire away.

 

Check this link out. Very clear and concise way as to how and why to purge ALL lines. According to this guy you want to purge all three and it makes a lot of sense.

 

I know this thread is super old.......but I think your problem is related to your radiator fan's low speed not working. When the low speed resistor breaks, the high speed fan will kick in intermittently just as you see in your video. If you stick your hand down between the bumper and the radiator with the high fan NOT running, do you feel the low speed fan running? If not, you need to look at the Low Speed Fan Resistor Mod thread. Link HERE. I'm trying to figure out why my wife's 06 MCS is blowing semi-cold air. For a second I thought I figured it out yesterday but now I can see the low side at about 40 psi with the high side very high at 350 with an ambient temp of 95 degrees.