Stress A/C system?

[xxch4osxx]

Also from the site: Will DURACOOL® harm my Air Conditioning and/or it's components?
DURACOOL® will not harm your AC system or it's components. In fact, it will actually add life to air conditioning and refrigeration equipment. This is because it is non-corrosive as compared to R-134a and the R-22 products that may breakdown into highly corrosive components. We even guarantee in writing that the use of our refrigerants will not harm your air-conditioning system.

 

[xxch4osxx]

Originally Posted By: Chris142
Lets end the HC talk right now.



It is illegal to use a HC refrigerant in 19 states including the OP's Idaho. The only refrigerants that can be used are R12 if the car originally had R12 or R134a in any car including a retrofit from R12.


What is the legal status of hydrocarbon refrigerants such as HC-12a® and DURACOOL®?
It has been illegal since July 13, 1995 to replace CFC-12 with the HC-12a® formulation that was submitted for SNAP review in any refrigeration or A/C application other than industrial process refrigeration. The same prohibition for OZ-12® took effect on April 18, 1994. Because DURACOOL 12a® has the same chemical composition as the HC-12a® formulation that was submitted for SNAP review (i.e., Hydrocarbon Blend B), DURACOOL 12a® is also subject to the same restrictions.

http://www.epa.gov/ozone/snap/refrigerants/hc-12a.html

http://www.imcool.com/articles/aircondition/Porsche_928_Refrigerant_Fire.php

I wish I could see the OP's car and get guage readings. It may be low or overcharged or have a blend door problem.
This does not apply here in Canada. There are no restriction on use of hydrocarbon refrigerants in cars.

 

[onion]

Originally Posted By: astraelraen
This is going to sound terribly dishonest... but its not! Short background.

New car's A/C sucks (1.5 years old ~8900 miles on it). I've brought it into the dealer a few times... they always find nothing wrong with it. The A/C performance is marginal at best. I can hop in my wife's Legacy under any of the exact same conditions and it will freeze my butt off.

From what I've gathered on the internet there might be a problem with the compressor. Failures are starting to crop up in the early 2007 model years in vehicles with as low as 20k miles. The people who have had their A/C fail and then replaced all have reported the performance is way better once the new compressor is put in. Some say that there is a new part # for a revised compressor, but I cannot confirm this.

I'm afraid that because I drive so few miles (I doubt that will break 15k by the time the 3 year bumper-to-bumper is up) that IF my A/C is defective and fails then I'm going to end up with a huge repair bill early in the life of this car.

Is there anything you can do to an A/C system besides running it constantly to try to stress the system? I'm not trying to sabotage my car... but if its going to fail because of a defect. I want it to do it before 3 years lol.






Not sure what sort of vehicle we're talking about here- so I can't comment as to the likelihood of the compressor being the problem... nor can I speculate as to what your problem might be.

But if you just want to stress the a/c system- here's how to do it: put a piece of cardboard over the condensor. Roll down the windows and run the a/c on high. Don't drive around, but keep the engine revved to at least 2000rpm or so- so that the compressor will be pumping enough volume. That will build lots of pressure in the high side.

Two cautions: Watch the engine coolant temperature. You might overheat the engine doing this. But if the day isn't very hot and you aren't driving around, you should be able to build LOTS of heat and pressure in the a/c system before the engine even gets warmed up. Also, lots of a/c systems have a high-pressure cutout switch that will disengage the compressor clutch if high-side pressure gets too high. If your compressor disengages during this experiment and the a/c isn't cooling at all, then you likely have such a switch... in which case you're going to have a hard time putting any excessive stress on the compressor.

Here's another idea. You might have a problem with dishonesty, but I don't. I cheat to win. I've replaced LOTS of compressors (including some under warranty) due to a leaking shaft seal (yes, folks... I know that shaft seals can be replaced. But sometimes that's a liability that I don't want to incur- and neither does warranty). If a shaft seal leaks badly, then it generally sprays oil all over the compressor clutch. Visually, refrigerant oil LOOKS pretty much the same as any clear oil- like power steering fluid. Hypothetically, if somebody were to dump a little power steering fluid on an a/c clutch, spread it around, and let it collect dust for a few days- I would likely diagnose it at first glance as a leaking shaft seal... and replace the compressor.

 

[demarpaint]

Glad someone else mentioned the oil trick first. It will work, just give it a few days to collect some dirt.

 

[brianl703]

Wouldn't a weak AC compressor show up as lower than normal pressure on the high side?

 

[pbm]

I wish the OP would identify the vehicle in question.

 

[demarpaint]

Originally Posted By: brianl703
Wouldn't a weak AC compressor show up as lower than normal pressure on the high side?


That lower pressure on the high side could also indicate the system is low on gas, or have a leak. A while back there were complaints from many new car owners of A/C systems not cooling properly. It was later found that the mfg's were under charging the systems slightly to save a few $$$. Most people had to have the systems charged up to spec to get it to function properly. I guess over 100,000's of cars under charging the A/C a few ounces really adds up. Maybe this is the case here?

 

[Propflux01]

Originally Posted By: pbm
I wish the OP would identify the vehicle in question.


He said a 3 year warranty, makes me thing it's a domestic.

 

[brianl703]

Why would you think that?

The following have a 3 year, 36K basic warranty:

Chevy, Chrysler, Dodge, Ford, GMC, Honda, Isuzu, Jeep, Mazda, Mercury, Nissan, Pontiac, Saturn, Scion, Toyota, Volkswagen.

I count 4 Asian manufacturers, 3 domestic, and one European in that list.

 

[440Magnum]

Originally Posted By: xxch4osxx
R134 can kill you if inhaled, unlike Duracool. Besides, hydrocarbon refrigerants have been in use in Europe for many years with no ill effects. I have no worries having Duracool in my vehicle, everything is flammable at the right temperature.


They BOTH will kill you the exact same way- by displacing oxygen and suffocating you. Any pure gas can do that. R-12, R-22, natural gas, propane, butane, hydrogen, helium, carbon dioxide, etc. will all suffocate you if you concentrate them and breathe them because they contain no free oxygen. R-134a is NOT toxic by itself. If you run it through an open flame, it will decompose into phosgene (deadly) and other components, but then Duracool (liquid petroleum gas) will just blow up.

 

[440Magnum]

Originally Posted By: brianl703
Wouldn't a weak AC compressor show up as lower than normal pressure on the high side?


A weak compressor will show up as an abnormally low differential between high-side and low-side pressures. You can
"fake" a normal high-side reading with a weak compressor just by over-charging the system, but it still won't work right because the low side pressure will also be too high. Another giveaway of a damaged compressor is an excessively "bouncy" high-side reading because when a compressor gets "weak" its usually because one cylinder isn't working (generally because of broken reed valves).

This touches on a key point: IF the original poster's AC system isn't working right, REAL diagnostic procedures can and will very likely locate the problem! There's no need to go screwing around trying to "stress" the da*n thing, just diagnose it. Problems that can't be revealed through simple diagnosis are very rare- things like an evaporator with a partial internal blockage so that only part of the coil is cooling the air come to mind- that will show perfectly normal pressures and yet have an abnormally high discharge air temperature- which in itself is a giveaway.

Since we still don't know what kind of vehicle it is, we can't rule out the possibility that it might have an inherently under-sized air conditioning system. There have been several vehicles over the years that were notoriously under-AC'd (the old Ford Aerostar comes to mind), and a few that had way more AC than they really needed.

 

[astraelraen]

Originally Posted By: Tim H.
Originally Posted By: pbm
I wish the OP would identify the vehicle in question.


He said a 3 year warranty, makes me thing it's a domestic.


Wow quite a response haha. I didn't quite think it was going to make it four pages long. Especially over a weekend.

Its a 2007 Mazda CX7.
TBH from reading I think part of the problem is a poorly designed system that wasn't built to compensate for the heat buildup in the engine bay from the turbocharger. So the A/C has to work even harder to cool the air. You would think placing the air on recirculate would help, but it doesn't really. The car also has a reasonably large passenger compartment with a black interior. And the front windshield is sloped at a pretty sharp angle... so it exposes a lot of the car to sun coming in the front. A lot of things working against the A/C... but you would think they would have compensated for that in the design phase...


In my opinion, the engine bay gets so hot during even "normal" driving that you can't even have the vent function on (no A/C) The air coming through the vents will be warm/hot depending on outside air temp. If its say... 70-80F outside, I can turn the vent on and be absolutely uncomfortable once the engine gets up to operating temp. I've lived in SC & Idaho and can tolerate some pretty hot & humid temperatures as well, so it's not me being a wimp

 

[bullwinkle]

Also possibly a bad expansion valve/"H" valve-not allowing enough refrigerant through the evaporator. Does the low side line (not the one that goes to the condenser in front of the radiator) get cool/cold and damp where it returns to the compressor? Sounds like a trip to a decent dealer svc. dept. might be a good idea.