AC blowing warm

[dlundblad]

Within the last couple weeks, I noticed my AC getting progressively weaker. A few weekends ago, I ended up recharging the system with a cheap kit (used it before on 3 other cars plus my Jeep issue free) and roughly a can of straight 134a (no oil, leak stop etc.). If this matters, I ended up using 2 cans, but when each was half full, they would no longer go into the system so the remaining halves were wasted. I recall having to do this before too.

Lately, it has been in the mid 80's to low 90's and it is still blowing warm.

Oddly enough, it almost feels like the airflow alternates between warm and cool, but more warm air blows out than cool.

What do you guys reckon it is? Something expensive that I shouldn't attempt myself I am sure.

 

[CharBaby]

Well, we're having the same issue with my daughter's '06 Mazda3i.

I have recharged the system now so, I know it "FILLED/CHARGED" according to the gauge. You can only fill the system while the compressor is running. To my knowledge, when the compressor stops, so does the charge until the compressor turn on again.

I believe it's the AC Clutch, at least with the Mazda in this case. Your's maybe the same. There are a bunch of YouTube video about either replacing the clutch, reshimming/removing shims or completely replacing the clutch...or even the whole compressor; let's hope we don't have to go there!

^^^I don't think so! Here's the video that helps me best and something I'd try myself. SMA has other AC videos and maybe even for a Jeep:

https://www.youtube.com/watch?v=DNx0X4INfiw

 

[RooflessVW]

I would recommend that all AC work be done by a professional with the proper equipment.

 

[pcoxe]

Many a/c's have a swinging door to regulate comfort temperature. If the door is stuck or in the wrong position you may be getting more heater air than a/c air. Some are controlled by air motors which can fail. Just saying, it's not always a refrigerant issue.

 

[RooflessVW]

Originally Posted By: pcoxe
Many a/c's have a swinging door to regulate comfort temperature. If the door is stuck or in the wrong position you may be getting more heater air than a/c air. Some are controlled by air motors which can fail. Just saying, it's not always a refrigerant issue.


Even if what you said was originally the case, it is now a refrigerant issue because he has added two cans.

 

[Brad_C]

This irritates me. I'm one of those guys that hates the advice "take it to a professional", but with A/C work unless you have the right tools at best you will get sub-optimal results and at worst you'll toast your compressor.

Undercharged : Bad cooling, bubbles through the expansion device causing compromised evaporator operation, oil starvation of the compressor, ultimately compressor failure due to compromised lubrication.
Overcharged : High head pressure due to reduced condensing capacity (making the compressor work much harder), liquid floodback potentially slugging the compressor and destroying valves. Overall at best a reduced compressor life and increased fuel consumption.

Difference between undercharged and overcharged? Less than 1/4 of a "can". The last European car I looked at had a charge spec of +/- 25g.

An amateur can do this stuff at home, but you need the right gear and a "can" with or without a gauge on it is not sufficient. To do it properly you want to weigh out the charge, vacuum the system and weigh the gas back in again (adding what you need to bring it up to spec - all cars leak to some degree). You can do this with a cheap recovery machine, some accurate scales and a decent gauge set (which I doubt you have or know how to operate). None of this stuff is rocket science, but it's one of those rare cases where a little knowledge can be a dangerous thing.

 

[spasm3]

You need to get gauges on it to see whats going on. You can check and make sure the cooling fan is working.

 

[WobblyElvis]

Originally Posted By: Brad_C
This irritates me. I'm one of those guys that hates the advice "take it to a professional", but with A/C work unless you have the right tools at best you will get sub-optimal results and at worst you'll toast your compressor.

Undercharged : Bad cooling, bubbles through the expansion device causing compromised evaporator operation, oil starvation of the compressor, ultimately compressor failure due to compromised lubrication.
Overcharged : High head pressure due to reduced condensing capacity (making the compressor work much harder), liquid floodback potentially slugging the compressor and destroying valves. Overall at best a reduced compressor life and increased fuel consumption.

Difference between undercharged and overcharged? Less than 1/4 of a "can". The last European car I looked at had a charge spec of +/- 25g.

An amateur can do this stuff at home, but you need the right gear and a "can" with or without a gauge on it is not sufficient. To do it properly you want to weigh out the charge, vacuum the system and weigh the gas back in again (adding what you need to bring it up to spec - all cars leak to some degree). You can do this with a cheap recovery machine, some accurate scales and a decent gauge set (which I doubt you have or know how to operate). None of this stuff is rocket science, but it's one of those rare cases where a little knowledge can be a dangerous thing.



What he said.

 

[KrisZ]

An AC kit with its cheap gauge has its place and time. "Bring it to the professional" advice is fine and dandy when it's not you own money on the line. And the said "professionals" are not all created equal either.

 

[exranger06]

I'll give a "+1" to Brad_C's post, but also wanted to add: Typically the compressor clutch will cycle on and off frequently when it's low on refrigerant. If it runs for 5 seconds or less and shuts off for about 15 seconds, then runs for another 5 seconds and so on, it's probably low.

Also, like Brad_C said, you can fix it yourself if you really want to, but you need the proper tools and learn how the AC system works. I was determined to fix my own AC system, so I bought several hundred dollars worth of AC tools, including a manifold gauge set and a vacuum pump. I've fixed a few AC systems with them and I think they've finally paid for themselves by now.

 

[JHZR2]

Now that you put leak stop in its anybody's guess, and, repair will become much more expensive.

You may have had a severe undercharge. But are you sure your fans are running, clutch engaging, etc?

 

[dlundblad]

Originally Posted By: JHZR2
Now that you put leak stop in its anybody's guess, and, repair will become much more expensive.


Re-read my first post. I specifically said I used straight 134a with no oil, leak stop etc.

 

[i_hate_autofraud]

In answer to the comments on half full A/C kits that fail to transfer the rest of the refrigerant, there's a fix:

When filling your A/C these kits get cold, very cold inside, that causes the pressure to drop enough that no more refrigerant transfers to the car A/C.

Prepare in advance a pot of hot water, rags and a small pot just big enough for the A/C kids can to sit in.

When you can tell transfer has slowed, soak rags in hot water and drape over and around the can, near the end, you can stand the can in the small pot and pour hot/ very warm water (100 F to 140 F) in to heat the can to build pressure to transfer all the contents.

I've never had to throw away a half-full can!

Older vintage cars have low pressure A/C systems, suction side pressure while running as low as 20 PSI ! Newer cars are all high pressure with low side running at 100 PSI minimum.

In the filling process, you'll need to start the engine and turn on the A/C so it sucks refrigerant from the can. The at rest, equalized pressure of near charged modern A/C is too high to let the full contents of an A/C kit to transfer, so running the engine and A/C is needed.

Usually 1 can does a whole A/C if fully transferred. Been doing it this way for years on various cars.

 

[SHOZ]

Are you running the AC at max fan and no recirc when trying to fill?

 

[dlundblad]

I can hear the clutch engage but I'll do a visual tonight.

When you guys say fans, do you mean cooling fans or blower motor? As for the cooling fans, my e fan hasn't worked in over a year (common 99-03 WJ issue) so I resorted to a mechanical fan on the water pump.

The blower motor is new and works great.

 

[SHOZ]

Blower fan, you want the highest load on the evaporator. You should hear the cooling fan go to high speed too.

 

[Lubener]

Just start putting freon in it without further investigation is foolish.Without gauges and knowledge, you either overcharged it (because of a blend door issue) or it leaked out as fast as you put it in.

 

[Lubener]

Originally Posted By: rooflessVW
I would recommend that all AC work be done by a professional with the proper equipment.


It was a bad idea that companies started making these DIY recharge items available to everyone.

 

[Merkava_4]

Originally Posted By: JHZR2
Now that you put leak stop in its anybody's guess, and, repair will become much more expensive.


He said a can of straight R134a -- no stop leak or compressor oil. You're slipping on your reading/ comprehension skills. And by the way, I still want the model number off your Milwaukee drill. I'm gonna start stalking you all over the board until I get it.

 

[mclasser]

Did the A/C blow cold at all after you added the cans of refrigerant?

Do some quick checks before going to a shop. On a hot day, turn the A/C on full blast. The compressor should run the entire time with almost no cycling. The cooling fans should also be spinning at max. Look at the condenser to see if it's clogged with debris or has many bent fins. Rinse it off with a low pressure garden hose and go for a test drive.