One thought: Say the system has a slow leak (technically they all do) and was indeed low. Some unnamed mouth-breathing chucklehead comes along and suggest adding a little bit of refrigerant to see what happens. A little too much was added, and although performance improved quite a bit, the system is now a little high. This might explain why performance is better, but not as good as it can be. Supposing the leak is still active, I'd be curious if performance increases in a few months as total refrigerant quantity drops back into the ideal range.

 

Thanks for the interesting info. Regardless 10 oz seems a good deal of loss in the system and it had to go somewhere. That is about a 40% loss. I suspect the same area of loss is still there.


T

 

It is why I had suggested a vacuum and the correct weight and then wait and see what happens. This guessing on refrig. fill is not what I like to do and that is what happens when you are just looking at pressure gauges.

TBB

 

Agreed, hands down! A full evac and refill by weight is the most accurate way to go. Then you know the refrigerant quantity is spot on, which will hopefully resolve any problems. If you have work done in a shop, that's what they will do because they don't want any callbacks.

But then again, I'm cheap and lazy. If I can get pretty darn close with careful guesswork, I'll review the risk/reward ratio. There's very little risk, other than possibly wasting half a can of refrigerant and bruising my ego. Contrary to popular opinion, there's virtually no risk of equipment damage if the refrigerant quantity is way high or low. You'll get poor cooling performance, but nothing gets hurt.

I definitely get why you'd want to know the servicing is done correctly. As for me, I'm willing to roll the dice and see what happens, because there's not much downside. Over the years, on many different vehicles, I've had about 80% success topping off the refrigerant, so am very happy with that.

 

The vehicle was stationary for the 45F at the vent. I believe like many of you have suggested that I have a leak and need to have this checked out. Any suggestions where the system weak points are for a leak. I am also thinking I should go to a professional with the correct equipment to detect the leak. What type of equipment is the best to detect a leak?

Thanks,
Howard

 

You could use a black light (you can get a flashlight version for cheap at Harbor freight if you have one near or even a home depot/lowes and look for the green dye, but you can pick up all sorts of other things like antifreeze, ect. However if you look at the path of all the AC parts and pipes and pay attention to the joints and around the condenser. A pro would use a Freon detector and perhaps a light to look around.
https://www.harborfreight.com/search...eak%20detector
https://www.harborfreight.com/uv-bla..._q=black+light

TBB

 

WOW. Thank you...I did not realize that a freon leak detector was that inexpensive.

Howard

 

I suspect you would find a leak around the condenser, pressure sensor or the compressor (especially pooling at the bottom of the condenser. Although any place that has an O ring is suspect. Some will say everything leaks and that is probably true to some degree, but not 40% of the system.

https://www.harborfreight.com/air-va...ors-96677.html
https://www.harborfreight.com/25-cfm...ump-61245.html

TBB

 

How much money do you have? Or more importantly, how much do you want to spend in pursuit of cold air?

If you had 45F air while working on the car, I think you will be pleasantly surprised with a road test. If the car is warm at all from the sun, expect 10-15 minutes on the freeway before reaching that mythical 38F target. Your AC system may be just fine as it is.

Does your car have a leak? All cars do. Those miniscule R134a molecules are little escape artists in a pressurized system seeking equilibrium. Even the most carefully sealed system will lose a little, maybe an ounce or so per year. How long since your system had a full evac and refill by weight? Just a guess, but say five years with an acceptable leak rate of 1.5 ounces per year, that would be 7.5 ounces short. Perhaps you slightly overfilled, too, which is easy to do. Adding 10 ounces may SEEM like a lot, but the time since the last measured fill is a huge factor. Remember, there's virtually no risk of damage if over or underfilled, just subpar performance.

Look at your cooling per dollar options. I suspect you will see pretty decent performance on the freeway. Even if not totally perfectly optimal, maybe you'll see a quite respectable 42F. But if the thought of a leak keeps you awake at night, expect to spend hundreds of dollars at a shop. They will charge an hour or so shop time for a leak check, and then a couple more hours plus parts for the actual repair. Then they will do a full evacuation and recharge, typically another couple hundred dollars. When all is said and done, you will be substantially poorer in exchange for maybe an extra degree or two in cooling performance. That's why I asked how much do you want to spend in pursuit of cold air, especially a possibly miniscule improvement?

If the thought of an unacceptable leak rate bothers you, you can do some diagnosis yourself. I've got one of these inexpensive sniffers and it set me back a whopping $29:



Poke around with one and see if it starts chirping anywhere. You might find something as simple as a loose fitting you can tighten.

The other factor to consider with a slow leak: You can easily monitor the AC performance over time and watch for a slow decay. Catch a small problem before it gets big. Keep a little el cheapo thermometer in the dash vent. It will help you discern a slow decline you might not otherwise notice until it got really bad, especially if the weather isn't super hot. Maybe you've got a big trip planned and don't want to be without AC. Just monitor ahead of time. Things might be just fine and no further action is required for years. Or the performance may indeed drop off after a few months, but you can decide then how to proceed. As cheap and lazy as I am, I hate to see anybody expend money and effort when not needed.

 

I redid mine after a full vacuum pull-down and weighed in the exact amount and even today I still get it to 37 degrees after 4 years. In Texas, it would be easy to notice if it became less efficient. So whatever I have lost, it is still in the range to get cold very quickly. Of course if it sits in 105 degree sun it does take some time to exit the heat load. I am not sure that a shop would charge him that much, but have difficulty finding shops I can trust and the dealership here- which is supposed to be highly rated- is the least trustworthy and has the absolute worst quality control of any operation in any industry I have ever seen. All for the most premium of dollars, along with a hefty degree of arrogance. I would just as soon give the car away before going to them.


TBB

 

37 degrees is great, but that's a LONG time to wait. My car consistently hits 38 after maybe only 10 minutes. I'll take that trade-off any day. Seems way more practical.

 

If my car comes out of the garage then it takes about 2-3 minutes of driving, even on city streets, to get that low. However if the car bakes in the hot dry sun of Texas and everything in the car is super hot and I am not on a highway, it does take some minutes to get the temp down. But I expect that.

TBB

 

The S-Type ( and X-Type ) A/C compressors are/were notorious for leaking, along with the EVAP cores. I've had several with the expansion valve fail as well. Occasionally the condenser will leak. The compressors also tend to get weak, more so on the high side, if you're able to watch the pressures while operating.

Other common issues are the dual heater control valves and the A/C control module. If the heater control valve shorts out, most likely it will take out the a/c module with it, this is even more present on the 03 Face Lift models and up as well.

The EVAP temp sensors have also been an issue as well, these are pretty easy to replace. You should get a code logged for sensor short to ground being most common.