Slow AC leak

hey guys,

So with how unusually warm it's been on the east coast I turned on my AC and it blew warm. This summer I recharged it because it wasn't too cold. I'm sure I have a slow leak in a connection I think. I know the compressor is good, what is a good leak finder kit, with the UV dye? I want to fix this problem sooner than later while I'm on break from college.

 

A lot of times seals on the compressor wear and leak slowly. Easy thing is to look for any oil around connections on lines or schrader valves. Could try spraying dish soap and water mixture around the same. A few simple thing you can try. More pricey tools can narrow it down.

 

That's what I am guessing because it's such a slow leak. 6 months and now it got warm, I think that's pretty slow. I know that in my parents Toyota Sienna, the AC went, i forget what major component but it would leak out the r134 in like a day. I am thinking its a seal on the compressor, or something inside the engine bay because there is no coolant smell in the cab

 

Pressurising with nitrogen helps the soap bubble test, but then it must be vacumed and refilled. If it identifies your leak, it dont matter cause you will open the system anyway to repair. You could also live with refills every year.

 

I will probably refill it, do the soap bubble test I guess?

 

Or get a uv test kit

 

You don't have a big enough leak for the soap bubble test to work. There is dye in the system from the factory, so get a black light and start looking around under the hood and under the dash. My bet is the compressor seals are shot, and you won't see any dye anyway. (but looking around with a black-light is the right place to start.) When the seals go the dye is hidden behind the compressor pulley or the leak is so small the dye just stays in the system.

I fought this battle with my wife's car. The charge would last from 4-6 months. I took it to a bunch of different shops and no one could find the leak. After spending a small fortune with no improvement I decided to take matters into my own hands and bought the necessary tools, including a vacuum pump. Long story short, doing it myself I was able to figure out that the problem was in the compressor.

 

A common leak location in the 1st gens is where the AC line goes through the firewall (part 8871004060)
Tough to see unless you pull the glove box. TRD Parts 4U: parts.toyotaofdallas.com/auto-parts/1996/toyota/tacoma/sr5-trim/3-4l-v6-gas-engine/hvac-cat is a good source for any any AC
line, or any Toyota part. Remember, you will have to put it under vacuum for at least an hour after replacing any AC component before recharging.

I had to do this in my 1996 around 14 years ago, no issues aat this location since the fix. Look for a little pink oil at the crack, unless you do a uv leak check.

 

very often, most often in fact, the leak will just be the schrader valves don't seal well and its a very tiny slow leak. they have very tiny little rubber seals in there that dry out and stop sealing properly. if its low just replace both schrader valves with new ones to eliminate that as a possible problem now or in the future.

the second most common is the spot where the lines connect to the compressor or the firewall which are just o-ring seals.

another spot is the front seal for the compressor but if that is leaking, then in most cases I just replace the compressor since most attempts at replacing the compressor front seals, they just end up leaking on you again.

wherever the leak is there will be a slight oil film that turns black from dirt so look for this in the areas of connections. if its the Schrader valve leaking then you will see oil film inside the cap.

DO NOT USE NITROGEN the tubing on the evaporator coil is only designed to handle 200-300 lbs of pressure and nitrogen is under very high pressure so you can instantly over pressurize it a lot faster then you can react to it and even if it doesn't burst then, it can weaken it and cause it to fail soon after.

Freon will have around 120 lbs of pressure on its own so that's all you need for leak testing. if that is not enough pressure for you to find the leak, then add UV dye to the system and the next time it is low, use a black light to see where the leak is. dye is not put in systems from the factory so its not in there unless someone put it in there for you at some point.

usually I tell people not to waste your time looking for small leaks you add Freon once a year and it lasts all summer. if that's the case then just do that and go on with your life. if and when it gets to the point it doesn't last and you need Freon more then once a year, then it is a big enough leak you need to fix it and you should be able to find it