Do AC systems need to be topped off occasionally?

Status
Not open for further replies.
W

WhyMe

Joined
Dec 18, 2012
Messages
1,327
Location
Washington for now
are they truly sealed and never need a top off? my 2011 honda is not blowing as cold as i like. everyone says they are sealed systems and should never need a top off and if it does it means its got a leak.

So is this true, or do they lose a little over time?
 
You might have a slow leak somewhere. A competent AC shop can check for such. My 13 Accord leaked down and it was the input? valve (looked similar to valve stem in a tire) leaking. They had a machine that pulled out the remaining coolant, replaced the valve stem, put back in old stuff stuff and added some to top it off. Cost: $60. This was a couple years ago. Its been fine since.
 
You get a few miracle vehicles that never need their AC system touched. I know of a few with over 200k and no issues.
 
Last edited:
Most vehicle AC systems leak a little, especially as they age. There is no perfect seal, especially in vibrating, heat cycling, cramped engine bay. Both our cars need a little top up once in a while. My Golf needs a minor top up every other year; the Mazda has needed a tiny bit once .
 
Originally Posted by WhyMe
are they truly sealed and never need a top off?


The problem with topping of is you don't know how much it lost and putting in just a few ounces too much will result in poor cooling as bad as you might have now with too little freon. R134A is so cheap (at least if you DIY) that you might as well vacuum it out and start fresh with a correct charge, assuming you have the equipment.
 
Since there's a mechanical seal at the compressor shaft, it could still ooze tiny amounts of refrigerant over years. It's not like the compressor in your home A/C or refrigerator where all the moving parts are sealed inside the compressor housing. I had a leaky schrader on my last vehicle that would leak; if I unscrewed the dust cap on the low side fitting I could hear a brief hiss. That one did leak down to the point it stopped working completely, and when I discovered the leaky schrader I made sure to screw the cap on tightly after having it recharged. Seemed to fix it, but if I unscrewed the cap it still made a little "psst".
 
Don't "top off", use a machine to pull it all out (and measure how much came out, to confirm the theory that some has leaked out over the years) then recharge with the specified amount by weight. This is the only way to be sure the charge is correct.
 
Last edited:
Originally Posted by mk378
Don't "top off", use a machine to pull it all out (and measure how much came out, to confirm the theory that some has leaked out over the years) then recharge with the specified amount by weight. This is the only way to be sure the charge is correct.

Correct. Never buy an auto parts store kit to recharge the system. One, because you don't know if that's the issue. Two, if it contains stop-leak the whole system is unserviceable and no shop will touch it by penalty of law. They will test it.
 
Well, if the AC is not blowing as cold and YOU KNOW THERE IS NO LEAK.
First, wash the condenser which is usually in front of radiator.
Go from there.

The R-134 refrigerant cannot be overcharged into a system.
So there is a chance that without the proper tools, you will overcharge and cause it to be blowing hot.
 
Originally Posted by scurvy
Most vehicle AC systems leak a little, especially as they age. There is no perfect seal, especially in vibrating, heat cycling, cramped engine bay. Both our cars need a little top up once in a while. My Golf needs a minor top up every other year; the Mazda has needed a tiny bit once .

That's what my FIL told me years ago, he was an HVAC guy and did auto AC for many years. Some leak a little. The older Fords leaked via O-rings at connections. I'd have to top my 88 E-150 AC up every 6 or so years.
 
Originally Posted by LotI
if it contains stop-leak the whole system is unserviceable and no shop will touch it by penalty of law. They will test it.

Who told you that line of bull excrement? No law that says I can't work on a system with stop leak in it.
 
Originally Posted by WhyMe
are they truly sealed and never need a top off? my 2011 honda is not blowing as cold as i like. everyone says they are sealed systems and should never need a top off and if it does it means its got a leak.

So is this true, or do they lose a little over time?


All systems eventually lose gas -some faster than others. In every car I've owned, the AC has functioned well for the first 5-6 years then, needed a 2-3 oz recharge. Back in the days of R22, I learned how to do basic AC system service. On the family cars, I usually do the work myself and have a complete set of hoses/gauges. When I do it now, I need to brush-up on the technique and get a current copy of the pressure/temperature tables.

Any automotive system that needs more than a few ounces of charge probably has a leak that needs to be repaired.

For folks who have no idea what they're doing, it's a risky proposition. If they insist on DIY... if they are working on a weak but functioning system, they should get an electronic scale and put in 1 ounce, test it for a while and add one more ounce. Repeat process until 3 (max 4) ounces have been installed. If it's still not vastly improved after that, take it for service at reputable place -Before blowing the system up to smithereens.

Ray
 
Originally Posted by Chris142
Originally Posted by LotI
if it contains stop-leak the whole system is unserviceable and no shop will touch it by penalty of law. They will test it.

Who told you that line of bull excrement? No law that says I can't work on a system with stop leak in it.


Theres definitely no law, but they should at least be honest. I had to have my Yellow Jacket 134 machine rebuilt because of it, 1100$ for new solenoids and valves.
 
Originally Posted by Audios
Originally Posted by Chris142
Originally Posted by LotI
if it contains stop-leak the whole system is unserviceable and no shop will touch it by penalty of law. They will test it.

Who told you that line of bull excrement? No law that says I can't work on a system with stop leak in it.


Theres definitely no law, but they should at least be honest. I had to have my Yellow Jacket 134 machine rebuilt because of it, 1100$ for new solenoids and valves.

you don't use the filters that separate the sealer from the refrigerant you remove?
 
Status
Not open for further replies.

Similar threads

H
AC components need replaced after leak?
Replies
6
Views
823
slomo
JellyBeanDriver
New radiator construction I haven't seen before - can anyone point me to construction info?
Replies
9
Views
762
ls1mike
F
Need Some HVAC Advice 2003 Suburban
2
Replies
23
Views
782
Fitz98
A
Change ac compressor and condenser?
Replies
8
Views
1K
Kurtatron
E
Any Air Conditioning Experts
2
Replies
21
Views
1K
KrisZ
Back
Top