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HI Ericthecarguy:
Happy Canada Day – a good way to spend a holiday is to stay dirty… if it would stop raining…
My latest woes are with the Air Conditioning system where it’s not cooling. I know A/C is a complex system so I did a little research, but still that doesn’t give me answers. The lay of the land is this:
1. The A/C compressor clutch assembly engages when the A/C button is turned on and disengages when the A/C button is turned off.
2. I know the assembly is supposed to engage and disengage at intervals. However, after running the car for 10 minutes, I haven’t seen it cycle. Usually by that time you would feel cold air in the cabin, but there’s none.
3. I don’t have a high/low pressure manifold – I just have low pressure one from a kit that I bought (but not refilled anything). So when I use the gauge from the kit, I see that when A/C is off, the pressure is 50+ PSI. When A/C is on, that pressure drops to 0 PSI.Why did I write 50+ PSI when A/C is off? Good question and here’s the answer – So I thought that 50+ PSI is a bit too much so I decided to let some pressure out. With the gauge attached to the low port, I open the valve on the other end (where you would attach a can of R??? gas). I hear air coming out – similar to what you hear from letting air off a tire, and the air stops exactly when the gauge reaches 50PSI. Next, I turn on the car and the A/C – the pressure drops to 0; after few minutes of running I turn off the car and I see that the pressure has risen to 52PSI. Again, I let some air out and it stops at 50PSI.
Now, I don’t know if this measurement has any significance. Is this a sign of too much air and not enough refrigerant in the system? Do I need to vacuum the system out and put some refrigerant in? What should I look for next? I try to avoid giving it to dealer or mechanics as much as possible.
PS The heating works, I know it’s not quite relevant, but thought I’d mention that.
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The gauge goes up to 50 psi when off is called static pressure.
The gauge is dive bombing to 0 from a possible low refrigerant
charge. see if this link helps.http://www.ericthecarguy.com/faq/solving-automotive-hvac-problems
AC issues can often be beyond the DIY. If you don’t find the problem with simple checks, I recommend you take it to a professional. If not, you could end up damaging the system and causing more problems.
The above article should get you started with those basics I mentioned.
Good luck and keep us posted.
UPDATE:
I went with the notion that the system is empty and the refrigerant has leaked out. The complete drop in pressure and the fact that the AC hasn’t been used since the purchase of the car in the winter of last year (add to that the number of months where the car has sat on the lot) – there’s high probability that the refrigerant was negligible, if any.
So I filled it with R12a refrigerant – new technology that’s a direct replacement for R12 and R134a and environmentally friendly (I know the name can be really misleading) Specs are here: http://redtek.com/English/product.asp?ID=18. I used a can of sealant in addition just to lubricate the O-rings and stop any minor leakages if any. I didn’t hear any big whooooosh so that’s a good indication of no major leaks.
Now when A/C is on, the pressure drops to 38PSI – which is normal operating pressure according to the instructions. The operating pressure was tested 4 hours apart and it still maintained the 38PSI. Cold air is blowing – I didn’t need a thermometer to feel the difference between the fan just blowing and A/C working. Over my test drive, I felt the compressor engaging and disengaging so it all seems to work. Over the next few weeks/months, I will be monitoring the performance.
As a note, yes I’ve read about mixing refrigerants. But with an empty system, I decided to proceed.
A couple of things that were covered in the article that was presented to you by Collage man.
Anytime a system hasn’t been used for some time, it’s a good idea to replace the receiver dryer to help prevent moisture buildup in the system. Moisture effects the operation of the AC system. Also, you made no mention of evacuating the system. This means that there was moisture along with contaminants in the system that could have been removed by vacuuming the system down before installing refrigerant. You can also use this to check for leaks as if the system can’t hold a vacuum, it can’t hold a charge. As stated, this was covered in the article that was linked.
Lastly, I’m not a fan of sealers, especially in AC systems. The operation of an AC system is dependent on a very small opening, the last thing I want to do is clog that up with sealant thus making the system inoperative.
Hopefully things work out for you. Sounds like so far they have. However you may have issues in the future due to improper service. As I stated, AC work is really not for the DIY.
Good luck and thanks for the updates.
Aaah yes, evacuation – I intended to do it – even got fittings to fit to my pump, but somehow my brain focused on refrigerant, sealer, and leaks, and nothing else registered. Much like a horse with blinders (not the first time it happens either)…
Question now is, is it worth evacuating the system now? I know damage may have already been done since the sealer have being circulating already.
yeah I know, I may have screwed this one up… :unsure:
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