97 F150 4.6
I have charged the system twice. It works great,might work for a day or two. Cooling super. Then it will just quit cooling as good then start blowing warm air. It has to have a leak somewhere but I have looked everywhere & cannot find one. It seems to lose it all at once.Is there a relief valve or something that could be letting it out. Don't here anything it just quits working. Like I said there has to be a leak somewhere but I have no clue where.

 

They have freon detectors, if they put some freon in your system and use this detector, they can pinpoint the location of the leak.

 

There is also freon with dye in it that will flouresce with a black light. Look for leak detector stuff (sorry for the lack of terminology) at the parts store. You might also ask Quintin; he's an HVAC guy in this forum.

 

most leaks in a auto systems usually is from the condensor and the compressor

 

I should have said that I did put dye in it. Still cannot find a leak

 

Could be the Evaporator, that is where mine started leaking and you will never see it. Any place else it would be easy to see, you would have a lot of oil (and your dye) around the leak.

Yes there is a Pressure Relief Valve at the back of the compressor on the
manifold and tube. But if it was blowing off it would mean you have a bad or bypassed Pressure Cut-Off Switch.

 

I recently had an issue with the loss of Freon, it took about 2 weeks. We tried a sniffer, and got false readings that would drive you crazy if you are not experienced in using it. We charged the system up with dye and located the leak finally. We were checking all hoses connections, and the compressor hub couldn't find it.

Then we decided to check the rear of the compressor, and there was the dye. Compressor was leaking near a bracket in the back of it.

Hope this helps,
Frank D