Have Jeep Questions? Ask a Jeep Repair Expert for Answers
Hello, you want to measure the outlet temperature with the thermometor at the outlet closest to the evaporator core. Usually it's the one all the way to the right on the passenger side. Outlet temp with the AC on recirculate and fan on high should be 36-40 degrees after around 10 minutes of the ac being on and traveling down the road at over 35mph. This inusures the system has had time to stabilize and good airflow over the condenser.
You can also check the high and low side pressures with AC on high and engine at 1500RPM I'll post the temp pressure chart below
The pressures are used to evaluate the charge in the system Look on that chart at the ambient (outside) air temp and what the pressures should be.
You can use the gauge from the empty can.
It will read without pulling the trigger. It will only work on the low side port. If you want to read high side as well you will need a complete manifold gauge set. They can be bought on eBay fairly cheap. Seeing both high and low side pressure is very helpful in identifying problems and I do recommend checking both.
I can and with recirculate on
You can use different brands of 134A.
Connect the blue hose to the low side , red to high side with valves closed. Crank up the jeep and turn AC on high. Allow it to run 10 minutes or so for everythingto stabilize.
Now's when you want to look at the chart below and what the pressures should be for your outside air temp. If it's just low on freon both pressures should be a little lower then what's listed.
This page explains the different readings and what they mean. If you're a litle unsure just let me know your ambient air temp and the pressure. Below is the chart with ambient temp in farenheit.
One other VERY important thing to note. DO NOT open the high side valve to add freon. Only open the low side valve to add freon to the system.
It will tell charge, if there's any restrictions and general health of the compressor
You will have to watch the high side gauge. when it goes up 10-20psi close the valve and wait to see what the pressures go back down to. IT's best to add a small amount many times then add to much and cause too much high side pressure.
That's correct. The high side is what you want to watch while the low side is open. When you are adding freon with the low side open the low side gauge does not show accurate system pressure. once you close the low side valve it's accurate within a few momentsl
You're welcome, I'm happy to share how to do it safely and accurately.
The high side looks fine, can you close both valves and take another pic?
I forgot HF gauges had valves on the couplers. OK with both closed on the manifold what the guages are showing is a restriction in the system.
You're going to need to change the expansion valve, it's stuck which is very common on expansion valve systems. It's located in te engine bay right on the firewall the two ac lines go into it. Once you change it out you'll need to vacuum the system and recharge it. The instructions are below
If it were low on refrigerant the high side wouldn't be as high as it is. What's happening is the expansion valve is keeping the low pressure too low. You could add freon and what will happen is the high side will keep going up but the low side will not change much.
The Valve is FOUR SEASONS 39014 it lists for around 15-20.00 most parts stores will stock it.
Yes, it will still blow cool. The expansion valve just has a piston that slides back and forth to control freon flow. I'll post a pic below. Actually here's a video that shows it at the 1 minute mark different year but generally the same to change. You might as well do the accumulator as well
That is the accumulator some may also call it the receiver/dryer.
By law the refrigerant will need to be recovered before opening the system. Once you have the refrigerant recovered you can change the parts and vac it. Some parts stores will rent you a vac pump or you can pick one up from harbor freight. The air powered one they have works fine with a decent compressor.
When you replace the accumulator you'll need to add 2.4oz (70ml) of pag oil. Also use pag oil to coat any O rings before installing them
You hook the vac pump up to the service hose on your manifold and open both valves, pull it down for at least 15 minutes then close the valves and make sure it holds vacuum.
Once that's done you can start charging. The freon capacity is 27oz so you'll need three cans but will use 2 whole cans and 3 oz of the last one. Basically put in the first two cans then watch the gauges closely when adding the 3oz from the last can. Walmart has regular 134A really cheap in 12oz cans, it's usually on the bottom shelf as they like to promote the more expensive ones with additives.
Expansion valve failure is really common in systems that use them. The piston inside the valve just wears out over time.
More than likely you'll be fine just replacing the valve, just don't leave the system open long as the accumulator will absorb moisture in the air.
Recovery involves using an AC machine to pull out the freon so it doesn't go into the atmosphere put is rather stored in a tank for later use, as per EPA regulations. Most shops charge .3-.5 hr to recover. If you had them change the valve as well you'd be looking at .7hr to have that done.
That's correct on the last 3oz just check the chart and match the pressures to your temp
The parts stores only loan the vac pump. The recovery/recycling machine will only be in a shop. You can likely call around and find a shop that will recover the freon pretty cheaply and even vacuum and charge it without charging for freon. Usually smaller shops are more friendly about things like this.
It's not a bad job. EPA regulations require it to be recovered....
Vacing is done prior to charging in order to remove moisture from the system as it's not compressable like the refrigerant.
Once you accept or rate the service a box pops up to give a bonus.
Nothing other than the freon coming out. If a hose is removed quickly and the freon contacts your skin it can cause frost bite.
That's correct, it would go into the pump and depending on the type it would contaminate the oil in it or if air driven just go into the air.
It will need to be vacuumed. Vacuuming causes moisture in the system to boil off.