Hey guys, new user here and I'm stumped again with this A/C system. There is a leak somewhere and I can't figure out where.

Last summer I replaced the evaporator and expansion valve, used orings and to my knowledge did everything right. I even replaced the bolts that connect the H and L side to the evaporator. Once I put everything back together, it still wouldn't hold a vacuum. I got it to about 12 but it would only last a few minutes.

So last week I brought the car to an A/C shop. They checked the entire system under the hood and they couldn't find a leak anywhere. They said they would tear apart the dash for me and check the evaporator for $125 and I said "Haha! No..." I just pulled out the evaporator again and it looks sparkly clean, perfect shape, not even a dent and no green "find my leak" fluid anywhere.

I'm really at a loss on what to try next. If everything under the hood is sealed (according to the shop), and the evap and expansion valve are sealed, what else is there?

 

I do apologize if this is a double post, but I was searching the site for about an hour and couldn't find anything relating to my problem

 

check the condensor for a pin hole

 

^not happening

You really have to pressurize the system to check for leaks. UV dye and a fluorescent light will be best. Its hard to check for leaks using a vacuum pump only. You'll be trying to listen for a hissing sound while that noisy vacuum pump is running and that's a waste of time.

After putting in the dye, check for leaks at all the connections. Even on the compressor clutch, sometimes the seal leaks there. I hope this helps, good luck.

 

I dont know if the halide torch works on 134A, but they do work great on r12.

 

Soap and water solution (with a high concentration of liquid soap). Partially charge system. Paint it on with a brush if possible. Observe for bubbles. Works to test natural gas connections too.

Or get a lamp to look for UV dye.

 

this

 

Thx for the replies. Basically you're all saying to recheck what the shop claims they did. So after listening to your advice, I added some dye, pressurized the system and found one leak right away. The filling valve where you add the Freon had a small leak once the system got up to about 55 psi.

I did notice that while the system was charged that the ac wasn't hardly cold at all. Its possible I didn't put quite enough in, but I emptied 2 12oz cans into the system.

 

Not sure what model you are working with but 2 12 oz. cans migth leave you over charged depending on your system. Usually you want 1.6 cans depending on the model/system. And typically between 4 to 5 oz. of oil for the entire system (each component requires a certain amount of oil). The cans 12 oz. hold ~330 grams. I've worked on cars that require 500-550 grams/1.6 cans (civics) and some require 600-650 grams/1.9 cans (accords and some civics). Some cars have an underhood sticker stating the amount. This amount is pretty critical to the proper functioning and performance of the system.
With an overcharge you could possibly damage your compressor (its rough trying to compress a liquid and having all that excessive head pressure).

 

Good advice. This is a 93 civic EX 1.6L. I'll lookup exactly how much it requires. I was going by ambient temperature and how much psi it was reaching.

 

keep in mind that addng the uv dye may make the low side port appear to have a a leak. it may be a good idea to replace the valve on both high and low sides while youre at it.

 

Did you ever figure out where the leak was ?

 

You might want to start a new thread with more details if you're experiencing a similar issue. This thread was started around 6 years ago and these members may not even be on Honda-Tech still.