btwakefi2

Hey yall,

So I have a Jeep question and I'm hoping to get some help. I'm a pretty novice mechanic so go easy on me. I have a 2000 Jeep Cherokee Sport with about 199,000 miles on it. About 7 or 8 months ago the A/C stopped working and began blowing luke warm air. At the time I didn't want to shell out the money to fix it so I've just ignored the problem and lived with the windows down approach. Well a few weeks ago the outside temps were reaching 100 degrees and I was dieing, so I decided to bite the bullet and take it to get it fixed. The first trip the shop told me it was just low on freon and the blower motor resistor was shot. They replaced the blower motor and added freon, called and said it was blowing cold and I could come get it. Driving off the lot it wasn't super cold, but colder than it had been the past months. I just figured it needed time to really kick in. The next day I got in to head to work and it was back to blowing luke warm, so I took it back to the same shop since I paid them and my problem wasn't fixed. This time they called and told me I needed to replace the Evap Core and the Accumulator and that it was going to be $1300. Well obviously I told them to go screw themselves and figured I'd tackle it myself. I changed the head on this Jeep myself so I didn't think this would be more difficult than that job. I had a friend help me and after a few youtube videos and reading up on some forum notes we started the job. Took about 2 hours but we had the dash off and the HVAC shell out of the Jeep. We replaced the evap core, the heater core since it looked a little rough upon inspecting it, and replaced the accumulator. We put the box back in, put the dash back together, turned the truck on and charged the AC. It came out cold for maybe 5 minutes before it went back to luke warm. Super confused we thought maybe the AC compressor was going. Bought a new one at auto zone, went ahead and got a new belt, swapped everything and it was still blowing out luke warm. At this point, when you turn the AC on max in the car there is an extremely loud squealing noise coming from the front of the car. Not sure if it's coming from the new belt or a pulley but god it is awful. Still puzzled, we though maybe the AC line was blocked, so I went and got a new one and replaced that. Still luke warm air. At this point I'm fed up, I've replaced everything I can think of, the evap core, the dryer, the ac line, the ac compressor and nothing is working. If someone could please help out and point me in the right direction or give me some advice I would greatly appreciate it. After doing all this work myself, I really don't want to take it to a shop to get it fixed unless I absolutely have to.

Thanks in advance!

Rambler65

Is the temperature blend door working OK? It could be mixing in hot air from the heater core which would give you warm outlet temperatures. The squealing noise could be from the belt not being tight enough, or possibly you're overcharged. What are the system pressures?

btwakefi2

Forgive me if this is novice, but how would I check to see if the temperature blend door is operating properly? The system pressures were reading normal when adding Freon to it according to the gauges on the AC Pro can. Are those gauges accurate or should I be using something else to gauge the charge? I thought the belt was tight enough, but I will go back today and test to make sure it is. is there any easy way to check to make sure its tight?

Thanks for any help

EZEARL

Only way to know for sure that your putting the required 180-200lbs of tension on a new belt.
http://www.rockauto.com/en/moreinfo....915781&jsn=298

Rambler65

As EZEARL said, the best way to check serpentine belt tension is with a tension gauge. (Though on mine I just made it "good and tight" and it's been OK. I do need to pick up a gauge though to check it for real.)

The blend door can be operated manually from under the dash:

https://www.cherokeeforum.com/f2/eas...3/#post3250058

Also it takes a few minutes for the engine and heater core to warm up. If the Jeep has not been heat-soaked from sitting in the hot sun and you're getting warm air from the AC right away from a cold start this is probably not the problem.

I assume you evacuated the system with a pump before charging? (Sorry for asking such a basic question, but I'm not sure if you mentioned that with the description of all the work performed.)

The low-pressure gauge that comes on those refrigerant cans is useless. To do a proper diagnosis you need a full gauge set. You can buy a set for maybe $50-$70 with some shopping around, or some of the big-box auto stores may loan them out. Youtube is your friend here, there are many videos showing how to use the gauges.

Here's pressure diagnostic info from the '99 XJ manual. I understand there were changes made to the AC for 2000, but the basic pressure information should be the same: