[mdelgado]

So the A/C light just blinks on me. Research tells me there are actually 12 sensors on this hvac system. So I just brought it in so they could put it on a scan tool. Come to find out its low on refrigerant. Crap! so there's a leak somewhere. I've never really dealt with A/C before, so what do you think? The shop said they can recharge the system and put a dye in it so they can find the leak with a black light sometime down the road for $150. Should I have the shop do it , or is there a cheap recharge can at the parts store with a dye additive?

 

[Dean]

Got a friend with a set of gauges? How about a leak detector?

IF there is zero pressure in the system, it needs to be evacuated, but I would check for the leak first by pressurizing with a little refrigerant.

If there is pressure in the system, leak check and add refrigerant

 

[any4xx]

Get ahead of the game by just adding some refrigerant with dye yourself. Any auto parts store will have the proper fitting/hose/can-tap for an easy fill. Once the dye is in, if it leaks out again it’ll be easy to spot the problem.

 

[mdelgado]

No, i don't have any friends with gauges or a leak detector. what's a leak detector? Like a leak down test?

I assume if I got a bottle at the parts store with the gauge on it, that will tell me if I have any pressure in the system?

Can you recommend a refrigerant with dye off amazon? They'll probably ship it to me faster than i can get to a store

 

[any4xx]

No, i don't have any friends with gauges or a leak detector. what's a leak detector? Like a leak down test?

I assume if I got a bottle at the parts store with the gauge on it, that will tell me if I have any pressure in the system?

Can you recommend a refrigerant with dye off amazon? They'll probably ship it to me faster than i can get to a store

The dye can be seen with a UV light and yellow glasses. If your system is truly empty, adding one can should give it enough life to at least turn on. It’s not REALLY technical to just add a can so long as you have the proper fitting, which again, you can get cheaply. I’ve seen cans at auto parts stores that already have the proper hose & fitting attached. The fittings are all standardized so you can only hook up to the low pressure side. Regarding brands, I think they’re all the same. 134A is 134A, so buy whatever you can find. Just start the truck, turn on the A/C, hook up the fitting and open the can, then wait. It may take a half hour for the can to empty, but if the can is frosty, you’ll know it’s discharging. If your system will hold any pressure your compressor should kick on within the first minute of charging.

 

[Dean]

No, i don't have any friends with gauges or a leak detector. what's a leak detector? Like a leak down test?

I assume if I got a bottle at the parts store with the gauge on it, that will tell me if I have any pressure in the system?

Can you recommend a refrigerant with dye off amazon? They'll probably ship it to me faster than i can get to a store

Probably not much difference in brands, just price.
https://www.amazon.com/s?k=r134+ref...e&crid=3RJKR1Y501DBX&sprefix=r134+refrigerant+with+,aps,240&ref=nb_sb_ss_i_1_22

The thing is you don't want to dump refrigerant into a system that has leaked down to zero and now has air in it. The air needs to be evacuated out first to avoid high head pressure and contaminants.

I never used a parts store bottle with a gauge so I don't know the answer but I would guess the gauge would show pressure in the system before you start opening up the bottle. (I always use gauges and a 30 Lb drum.)

Anyway, dumping refrigerant into the suction side with engine running only takes a few minutes, not an hour.

I use a leak detector a little like this one.

 

[mdelgado]

Since my system is in a safety mode and won't engage the compressor, should I put a can in first before starting? or start and have someone keep attempting to turn on the a/c while i inject the 134a?

 

[mdelgado]

Probably not much difference in brands, just price.
https://www.amazon.com/s?k=r134+ref...e&crid=3RJKR1Y501DBX&sprefix=r134+refrigerant+with+,aps,240&ref=nb_sb_ss_i_1_22

The thing is you don't want to dump refrigerant into a system that has leaked down to zero and now has air in it. The air needs to be evacuated out first to avoid high head pressure and contaminants.

I never used a parts store bottle with a gauge so I don't know the answer but I would guess the gauge would show pressure in the system before you start opening up the bottle. (I always use gauges and a 30 Lb drum.)

Anyway, dumping refrigerant into the suction side with engine running only takes a few minutes, not an hour.

I use a leak detector a little like this one.

huh, never knew that tool existed. I would just assume, no refrigerant automatically means there's a leak.

How many cans should I start with would you estimate?

I didn't know if I could get away with buying one of these kits

https://www.amazon.com/Interdynamics-MAC-134-Refrigerant-Refill-Charging/dp/B004BSNNY2/ref=sr_1_2?keywords=car+a%2Fc+recharge+kit&qid=1558023678&s=gateway&sr=8-2

 

[Dean]

Well, there has to be a leak if the system is low but if you can't determine if there is any pressure in the system now, dump a can in, stop the engine and look/listen for leak (sometimes an oily spot).

Probably 90% of the time vehicles still have some refrigerant in them.

Turn the can upside down and dump liquid in until the gauge shows around 35 PSI and the air coming out of the vents is cold.

(I usually open all the doors and put a fan in front of the condenser while adding refrigerant.)


And hope for the best.

 

[BillK]

Dean can probably verify this but I have been told never to use the parts store R134 that has sealer in it. Just the raw 134. Not sure if you can buy it with die that does not also have the sealer.

I just did the entire system on my 99 Tahoe. It had been leaking around the compressor body for quite some time. Had been nursing it along with a can every once in a while but it finally gave it up at 250K miles

 

[mdelgado]

Yeah, I'd rather not use a 'stop leak' and fix it right. My thinking, why put a dye in it if it's supposed to stop the leak? to show you the product doesn't work? jk.

Looks like you can get glasses and UV light for $12 and the gauge and hoses for $10. How many 12oz cans do you think I should start with. This enviro stuff has dye

Amazon.com: Enviro-Safe R134a AC Refrigerant + Dye 6 Cans: Gateway

 

[BillK]

Mike,
I don't know if that is what I would use. I would go to WalMart or Advance Auto Parts and buy a single can of straight R134, the real stuff, not "equivalent to" If one can doesn't get it running then you might as well have someone find the leak and fix it right.



If you start putting anything other than real 134 in it the guys at the shop are not going to be happy when the time comes to do it correctly.


Just my opinion,

 

[Dean]

That ad says it is R134A with a brand name of "Enviro-Safe"

It wouldn't say R134A if it isn't.

I personally wouldn't put any stop leak into a system myself.


{edit} Wait, it does say R134A replacement on the can

 

[mdelgado]

I agree, I'll go to O'reillys and get real r134 and let you know how i make out

 

[DUTCH MAX HEADWORK]

If you like your a/c and your pocketbook, you'll invest in a set of a/c gauges. Without them it's all a big crap shoot. They will pay themselves off quickly.

 

[mdelgado]

If you like your a/c and your pocketbook, you'll invest in a set of a/c gauges. Without them it's all a big crap shoot. They will pay themselves off quickly.

Yeah, I need to invest in some experience too. Funny of all the years of working on my own cars I've never had A/C issues, and this is the newest car I've owned... I think the plan is to throw some 134 and dye in, hopefully find the leak and replace the part. Then bring it to a place to have the system vacuumed and charged correctly.

It's just so ironic, I never bring my vehicles to shops. But I got a recall notice for the efans. So what the heck, free labor and new parts, so I do it. Get the hoe back and rad is leaking. After a couple weeks of adding fluid, I replace the rad. Next week, (in the Fall) a random humid day, turn on the A/C....blink..blink. tough to point finger, but

 

[70montee]

Mike,
I don't know if that is what I would use. I would go to WalMart or Advance Auto Parts and buy a single can of straight R134, the real stuff, not "equivalent to" If one can doesn't get it running then you might as well have someone find the leak and fix it right.



If you start putting anything other than real 134 in it the guys at the shop are not going to be happy when the time comes to do it correctly.


Just my opinion,

This. I would make overly certain that whatever you put in is R134A. The makers of the "happy homeowner" quick shot A/C stuff seem to be very good at making people think what they are putting in is R134a. I guess i dont have a huge problem with those quick shot cans for small tune-ups, but you might as well have your eyes closed when putting it in. There is now way whatever little gauge they supply you with is accurate to whats really going on.

I imagine lots of vehicles are being over charged my people throwing this stuff in willy - nilly

 

[mdelgado]

Alright, so I took my charge hose with me to O'reilly to make sure i got the right fitting and can. They had a r143a with dye, so I picked that up and a can of regular r134a. I was advised that my hose was the old style and I needed the adapter, so another $3. That also saved me a 2nd trip back. There's something to be said for going to a real store and getting service, compared to buying online..
Anyway, I started the car and hooked the can to the low pressure and the compressor engaged almost instantly. Whats odd is that it engaged and then 4 secs later, disengaged and did this repeatedly. When engaged, the meter would read in the green low. then when the disengaged, the meter would spike to red, danger area. Then it cycled back on and was a little high. off, and spike again. on, and now in the Blue Full area. it was blowing cold air and full when compressor was on so i stopped and didn't put the other can in. Why does it spike in pressure when the compressor disengages?

 

[Dean]

How low did the pressure go with compressor running?

Low pressure with compressor running = Low on refrigerant, high pressure with compressor off is pressure in bottle I bet.

I guess the gauge won't show the pressure in the system with compressor off ???

 

[mdelgado]

How low did the pressure go with compressor running?

Low pressure with compressor running = Low on refrigerant, high pressure with compressor off is pressure in bottle I bet.

I guess the gauge won't show the pressure in the system with compressor off ???

I think the lowest it got was 20#. makes sense what you said, the meter is reading the pressure inside the can when the compressor is off