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fluctuating low side pressure and 134a shoots out relief valve well driving

JoshuaSulwer on Sun August 09, 2015 2:50 PM User is offlineView users profile

Year: 2000
Make: chrysler
Model: sebring convertible JXI
Engine Size: 2.5 L
Refrigerant Type: 134A
Ambient Temp: NA
Pressure Low: 30-90+
Pressure High: too hot

2000 chrysler sebring convertible coupe 2.5L 144k miles
First off please forgive my ignorance, my main teacher has been poverty and necessity; plus in 110 plus degree weather and working 64 hours minimum a week and the constant reasonable expectations to provide for my family: My best sometimes is slightly compromised to say the least.

AC worked great, then 1 day quit without signs. Noticed The high side cap was a little loose and could hear a lite hissing, proceeded to tighten cap-a half turn or so and hissing stopped. Planned on replacing the shradder valve stem but when I took the cap off w a new valve stem in hand there was a rubber plug under the cap that was wedged in there good over the valve. When charged and cap tightened it didn't leak so I left it alone for now because I only assumed there would be a shradder valve on the high side too.

Added approx 7 oz w a lowside only manifold reading 45psi when finished, w 0psi at first. ambient temp 110 F, 10% humidity. blowing cold in park, start driving and PTCHHHHH (noise, cloud) and warm air blowing out ever after. Reading 0psi again. Also I didn't bleed the air out of the manifold line before connecting it the first 2 times I tried tried charging it and also I had the can upside down because it would fill way faster Later I read that is wrong because it adds liquid 134a instead of gas. Possibly regardless, on the 3rd attempt with the can upright as they sit on the store shelf with a 12 to 3 motion and taping and bleeding the air out of the line before attaching- the same thing happens. Also the low side pressure fluctuates as the compressor cycles on and off from 45psi to 90plus (gauge maxes at 90) Also it only takes 3-7 oz to go from 0 to 45psi. Even if I add just enough to get it kind of cool at 30psi it will shoot out the relief valve within a minute of accelerating. Also the high side lines are too hot to touch. I hear they are suppose to be around 110F, sometimes I will flip food by hand in my personal frying pan at 165F and it doesn't hurt like it does to touch the high side line, so I'm assuming the pressure there is higher than it should be if 110F is ~350psi: based on the theory of more pressure equals higher heat. Also from the expansion valve the small line is ice cold going to the dryer and line frosts even now that its not blowing cold, but compressor clutch is engaged and fans work high and low speed properly. From the dryer the high line is still super hot. The large low side line is luke warm and reading 0 psi; but if I turn the car off and try to connect to the low side it spikes the gauge passed the max of 90psi.

I am pretty certain I have a clog, but where? I have a expansion valve easy to access, but everything I read and watched doesn't make it sound like that is it. (but I am not convinced what I have learned online so far is accurate)
I'm considering just doing a proper evac and vacuum, but I'm going to have to do that anyway if this sounds strongly like any particular part of the AC system is failing.

Please help and please keep it corrective criticism; someday my children may read this, thanks.

Thank you

mk378 on Sun August 09, 2015 5:39 PM User is offline

You need a proper gauge manifold so you can see both pressures. The high side is much more informative when you must charge by pressure. Starting from an empty system and charging by weight is preferable.

Popping the relief valve is usually because the condenser fan does not work, or the system is overcharged.

A leaking ball type high side fitting is replaced by unscrewing the whole thing from the line, system must be empty.

Edited: Sun August 09, 2015 at 5:40 PM by mk378

bohica2xo on Tue August 11, 2015 11:34 AM User is offline

Sounds like a condenser full of previously exploded TRS090 bits, or magic in a can sealer. Perhaps a little air too. Or maybe just 22 ounces of oil...

No worries, just keep adding things through the low side with no high pressure readings and that compressor will eventually give up too. The really fun part of blowing up a TRS090 is when the parts go through the case. Best to wear safety glasses when that happens.

In other words, stop what you are doing. Buy or borrow a proper gauge set and test the pressures. Right now your compressor is ok, but if you keep hacking at it you will kill it.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ice-n-tropics on Wed August 12, 2015 3:24 PM User is offline

1) If the small line between the drier inlet and the condenser outlet is frosty, the condenser is partially plugged. If it's frosty out of the drier only the drier is restricted
2) TR scroll compressors generate aluminum fines as the anodized orbiting scroll rubs against the softer aluminum fixed scroll, thus as the scrolls run-in and the volumetric efficiency improves as the scroll shapes conform and gas bypass between scroll walls decreases. Oil is gray color in a used scroll. These alum fines lodge under the pressure relief valve (PRV) as it reseats and the original 425 to 500 psi pop off pressure may not be restored and a new PRV req'd.
I have a complete new similar radiator & condenser & dual fan assembly for a Dodge V6 Stratus in my shop if you are interested

Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

Edited: Wed August 12, 2015 at 6:04 PM by ice-n-tropics

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