I bought a used civic about 6 months ago and now that it is summer I found out the AC blows hot air. I bought an AC recharge kit and hooked the gauge to the low portion tube and the gauge reads 0 and the compressor doesn't spin up at all. I put some of the recharging can into the system and the pressure was up to green on the gauge but the compressor still didn't spin up at all and I wasn't comfortable adding pressure past the green without the compressor spinning up so I disconnected the gauge and the pressure I had built up vented its self, reconnecting the gauge reads 0 pressure again. should I just take it to the mechanic at this point or is it actually ok to increase the pressure more if the compressor isnt turning over?

 

Refrigerants are a condensible, so you likely did not damage your system at all. Once the system has enough refrigerant to condense into a liquid the pressure will only really respond to temperature changes when the system is off unless you (somehow) put like 10 pounds in. You can hold that charge hose on there all day with the system off and it would not go past 'green' since it already has enough refrigerant to condense inside the system. It's not moving anywhere since the pressures are technically equal between the can and the system. I tried this with my refrigerant tank and scale and it only needs like 3oz before you need to run the car to continue charging from a deep and empty vacuum.

You can't tell at all what's going on with one of those single hose walmart death kits, and A/C units are complicated enough where if you have to ask questions, it should usually be taken in. A/C work usually requires several hundred dollars in equipment and some knowledge to do properly. You can't just get those A/C mechanic in a can things and make it work. Those usually screw up a system far worse than it would ever need if just fixed properly from the start.

Try to find a dedicated A/C shop, and not Walmart or some Jiffy Lube. You most likely have a leak somewhere that must be fixed. Your system will need to be recovered (if refrigerant present), pumped down into a vacuum to remove all air and moisture, leak checked and recharged. In my area it's usually around 60 bucks for a service like that. They'll even be able to point out where your leak is, and we can help determine if it's a reasonable amount to fix.

If you're adamant on fixing it by yourself (which I would not recommend without someone to learn from), at LEAST get a gauge manifold set, an electric vacuum pump, a can tap, and start watching a LOT of youtube videos. Just know that you're still ballpark guessing a charge unless you buy a refrigerant scale and preferably a 30lb tank of R134a. You'll pay around 200-250 initially in equipment, and 400-600 if you go for tank and scale, but it pays off in the end if you get the hang of it.

 

first check the clutch air gap with a set of feeler gauges, it should be between .014 and .026 inches

if the clutch air gap is good, jump the ac relay and see if the clutch engages, if not, then it's likely the coil is bad

 

Thanks I'll just bring it in to the mechanic then.