R134 Not Cold Enough - What to add?

wnangle

Member
Mar 14, 2007
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I have 2002 Jeep Cherokee. The R134 AC is reasonable, but has never really gotten down to COLD. On a 90 degree day, it will keep you cool'ish and barely prevent a sweat on my brow, but any hotter it just cannot keep up. I've had the unit checked, and it is full of refregerant, belt is tight, and all other AC functions are in the normal range. What I'm looking for, as an individual, I have heard about various other gases that can be substitued or added to drop the temperature. I can do the work my self, but just need to know what type of gas to put in? Can I put R12 in an R134 unit? I have a few pounds left over from yester-year. Since the reverse can be done, why shouldn't this work? I've also heard many people talk about propane? Can propane be mixed with R134? I'm only interested in getting the inside temperature as low as possible. Has anyone had any success with some of the additives that 'Claim' to lower the inside temperature? Perhaps some refrigerant blends? What will result in the coldest temperture?
 

Zysoclaplem

Diamond Member
Sep 26, 2003
8,799
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Well to go from r12 to r134a you have to flush and convert your system. So yes, I am sure you can flush and convert to r12. But r12 is hard to find, and even if you have a few cans, you will run out eventually. You might have a compressor leak? r134a is not near as cold as r12. I wouldn't mess with it myself.
I am sure there are tons of tutorials and articles about in in other forums. You might just go a google search.
 

ValValline

Senior member
Feb 18, 2005
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First off I wouldn't make any change to the type of refrigerant in the system. Mixing chemicals is bad and can lead to all sorts of issues down the road.

How was the system checked and was it checked properly? A visual inspection of the sight glass for bubbles, or even hooking up gauges and taking a reading is often not enough. Especially if it isn't checked on a 90 degree day under normal conditions. A proper check includes hooking up gauges and comparing the readings to a chart based on current ambient temps. Even if the guage readings are within normal levels, it doesn't mean the system is charged properly.

An AC system is just that a "system". You can part of the work yourself. Start by inspecting the condenser in the front of the vehicle. It will look like a mini radiator in front of the real radiator. Make sure it is clean and free from damage. Make sure you look between the condenser and the radiator. This area is often missed, and if it is plugged with debris (leaves etc) it can really reduce the performance of both the AC and engine cooling.

Next take it to a shop that knows what they are doing. To properly service the system it needs to have the refrigerant recovered and then drawn down to a vacuum before filling to proper levels. If it isn't drawn down to a vacuum then you have 14.7psi of ambient air partially filling a system that should contain nothing but R134 and some compressor oil.

The bottom line is that your Jeep should have working AC without having to resort to different chemicals.
 

lightpants

Platinum Member
Aug 13, 2001
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76
Originally posted by: smack Down
I hear propane works much better then r12 or r134.

hmmmmm, I wonder why everyone doesn't use it then....

Listen to ValValline, a 2002 jeep's a/c system working correctly will have no problem cooling the passenger compartment. Take it to a good mechanic and they will get it working correctly.
 

iamwiz82

Lifer
Jan 10, 2001
30,772
13
81
Originally posted by: lightpants
Originally posted by: smack Down
I hear propane works much better then r12 or r134.

hmmmmm, I wonder why everyone doesn't use it then....

Listen to ValValline, a 2002 jeep's a/c system working correctly will have no problem cooling the passenger compartment. Take it to a good mechanic and they will get it working correctly.

Propane is a very good refridgerant, but that whole exploding thing is a bit of a downer, ya know? ;)
 

wetcat007

Diamond Member
Nov 5, 2002
3,502
0
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You can get a canister of R134a at Target with a pressure gauge for 20 bucks. I'd recommend not using R12 in your system, many newer systems are only supposed to use R134a.
 

ManBearPig

Diamond Member
Sep 5, 2000
9,173
6
81
i just bought a new camry (2007) and have this same problem. i took it to the dealer and he basically told me it takes a while to cool, and barely cools when it does (especially on hot days). exactly like what you are describing...i freaking hate it...
 

Kelvrick

Lifer
Feb 14, 2001
18,422
5
81
Do you have that problem at highway speeds? I usually only see 134 having problems at stoplights. Maybe beef up the fans up front.
 

lightpants

Platinum Member
Aug 13, 2001
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Originally posted by: iamwiz82
Originally posted by: lightpants
Originally posted by: smack Down
I hear propane works much better then r12 or r134.

hmmmmm, I wonder why everyone doesn't use it then....

Listen to ValValline, a 2002 jeep's a/c system working correctly will have no problem cooling the passenger compartment. Take it to a good mechanic and they will get it working correctly.

Propane is a very good refrigerant, but that whole exploding thing is a bit of a downer, ya know? ;)

exactly!


The deal is, Jeep sold many thousands of Jeep grand cherokees in 2002. If there were and engineering defect, you would hear about it. There is a problem with your jeep, get it fixed and you will be happy. If you take is somewhere and they say they cant get it colder, take it somewhere else.
 

ValValline

Senior member
Feb 18, 2005
339
0
76
Originally posted by: Heen05
i just bought a new camry (2007) and have this same problem. i took it to the dealer and he basically told me it takes a while to cool, and barely cools when it does (especially on hot days). exactly like what you are describing...i freaking hate it...

On an extremely hot day (90+ and the car has been sitting in the sun all day) in stop and go traffic, it may take 20-30 minutes for a R134 system to get as cold as it is going to get. Once it does cool down it should be cold enough to get uncomfortable if you hold your hand close to the vent at the lowest temp.

I used to be a Toyota/Lexus mechanic back in the late '90s. It was rare, but we would get new cars with over/under charged AC systems right off of the truck. There is a reason why dealers run every new car through a cleanup and inspection process before putting them on the lot. Sadly most mechanics do it half-assed, because new cars rarely have problems.

My guess is if they checked at all, they took a look at the sight glass (bubbles means it's low on charge, but proper and over charged both appear clear), and ran the car in the shop for a few minutes. It takes time to hook up gauges, and there is no profit in it for the mechanic to spend a lot of time testing for a repair that pays very little under warranty. Just about any car with a half-working AC system will cool off in a shaded well ventilated shop no matter how hot it is outside.

Go to your local auto parts store and pick up a thermometer. They should have a cheap one you can stick into a dash vent. See how cold the air gets coming out of the vent with max AC on a hot day after 20-30 minutes of driving. If it doesn't get down to the low 50s or high 40s, then take it back to the dealer and insist they check it again. Request gauge and vent readings and make sure they are documented on the work order. I know it sucks, but you have to be a squeaky wheel if you want it to be right.
 

Shawn

Lifer
Apr 20, 2003
32,236
53
91
My friend used to work with commercial buses. His boss would put in 10% of whatever refrigerant the buses used and 90% r134a in all of his cars and they would blow ICE COLD! He said if he added any more than that it would freeze over.
 

dmcowen674

No Lifer
Oct 13, 1999
54,889
47
91
www.alienbabeltech.com
The refrigerant temp is not the problem.

The problem is volume/evaporative issue.

Make sure you have the air on re-circulate if you have that option.

Many older vehicles did not have a re-circulate flap.

2002 Jeep I would think has it but I don't know Jeeps.

Leaving outside airflow adds to the humidity level of the air coming in that the ac is already trying to cool/dry.

Get your windows tinted with reflective tint.

Good luck
 

Sukhoi

Elite Member
Dec 5, 1999
15,350
106
106
Originally posted by: dmcowen674
The refrigerant temp is not the problem.

The problem is volume/evaporative issue.

Make sure you have the air on re-circulate if you have that option.

Many older vehicles did not have a re-circulate flap.

2002 Jeep I would think has it but I don't know Jeeps.

Leaving outside airflow adds to the humidity level of the air coming in that the ac is already trying to cool/dry.

Get your windows tinted with reflective tint.

Good luck

IIRC if your interior temps get too low while you have it on recirculate you will freeze the evaporator.
 

dmcowen674

No Lifer
Oct 13, 1999
54,889
47
91
www.alienbabeltech.com
Originally posted by: Sukhoi
Originally posted by: dmcowen674
The refrigerant temp is not the problem.

The problem is volume/evaporative issue.

Make sure you have the air on re-circulate if you have that option.

Many older vehicles did not have a re-circulate flap.

2002 Jeep I would think has it but I don't know Jeeps.

Leaving outside airflow adds to the humidity level of the air coming in that the ac is already trying to cool/dry.

Get your windows tinted with reflective tint.

Good luck

IIRC if your interior temps get too low while you have it on recirculate you will freeze the evaporator.

He's not getting very cold inside so certainly doesn't sound like he has that to worry about.