Steve Smith

Just bought my 2005 JGC it has 135k miles on the body and 90k on the engine. Couple of questions.

Aren't you supposed to check your coolant level when the engine is cold? As opposed to hot for checking the oil? I checked the coolant resevoir in the morning and the resevoir was empty. After about 30 minutes of driving I checked it again and there was coolant just under the "low" mark. I've been very happy with the engine's operating temps since I had it, not one complaint so I don't know what to do. Thinking about filling it to the "low" level in the morning.

When I drove away with my Jeep everything was great. Than a week later I decided to hit it with some engine degreaser since it's kinda old and it needed it. Now the ac compressor doesn't come on and the EPS light pops on once in a while. None of which happened before I engine degreased. I made sure to avoid the pulleys/belt with the water/degreaser. I don't believe in coincidences and I'd like to check any sensors/relays/switches that have to do with the ac. The ac light comes on in the car but the ac does not engage. The ac worked fine when I bought it and there were no warming lights on at all before I degreased. Same with the EPS......any sensors/relays/switches I'd like to check out.

The EPS barely comes on and when it does it flickers. I feel if there were a legit problem with the steering system it would stay on consistently.

Thanks for the help.

Noah911

I know a little about the a/c. There are three things to check for when the compressor is not working. First, is to check refrigerant level/psi. If it is low, the compressor will not engage as a safety mechanism to prevent damages. If the refrigerant psi is low, you can fill it up with any r-134a can from the store (these cans generally will come with the hose and gauge to see what the psi is initially). When you recharge and fill it up again, the compressor should engage now if that was the issue. The next thing to check would be fuse, switch, relay, or wires. I don't know what or where those would be on your specific model, but maybe someone else does? Or, you could look it up to find the schematic for your particular model and year easily. The final thing to check would be the compressor and/or its clutch. They can get worn and out of spec over time. There are good videos online to explain this better.. Basically, you open it up, find the shim(s), and then remove one of them to get it close to being back in specs again. It's kind of like checking valve clearances with a feeler gauge in a way. There is a spot to check the clearance on the compressor/clutch. You can use a feeler gauge to actually check and see how out of spec it is, comparing yours to an official service manual. You can then measure the shim(s) if you want, do the math, and remove the one that will get you back close to the original reccomended specifications (sometimes there is only one shim to remove irregardless). It looks very easy to do, and applies to most every vehicle a/c compressor or clutch components in any make of vehicle. If thats the issue, it should work to get your compressor engaging once again for a few more years.

SOMETIMES there are differnt things too... I don't know about it, but copied & pasted this for you (I believe it is for the 2005 Cherokee 3.7L V6):

OPERATION

Here is information on how to gain access to it. The best way to diagnose this is through the use of a scan tool. If you do not have a scan tool, check with your auto parts store. They can rent one to you.



Chris

REMOVAL

WARNING: Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible personal injury or death.








NOTE: LHD model shown. RHD model similar.

1. Disconnect and isolate the negative battery cable.
2. On LHD models, remove the instrument panel silencer from the driver side of the instrument panel.
3. On RHD models, remove the glove box from the instrument panel (refer to 23 - BODY/INSTRUMENT PANEL/GLOVE BOX - REMOVAL).
4. Disconnect the HVAC wire harness connector (1) from the evaporator temperature sensor (2) located on the left side of the HVAC housing (3).
5. Remove the evaporator temperature sensor from the HVAC housing

Noah911

From the Owner's Manual:
Engine Coolant Level
The coolant bottle provides a quick visual method for determining that the antifreeze/coolant level is adequate.With the engine idling, and warm to normal operating temperature, the level of the antifreeze/coolant in thebottle should be between the ranges indicated on the bottle.The radiator normally remains completely full, so there is not need to remove the radiator cap unless checking forantifreeze/coolant freeze point or replacing antifreeze/ coolant. Advise your service attendant of this. As long as the engine operating temperature is satisfactory, the coolant bottle need only be checked once a month.

Joel Burgess

Good info, all! I've got a 2000 Jeep Cherokee Sport and the AC isn't working.

I checked the coolant level and it's is fine. But then I realized the clutch isn't moving.

The interesting thing is that if I turn the Jeep on I can nudge the clutch with a screwdriver and it does start spinning and cycling on and off - like I think it's supposed to.

But eventually it just stops. So, reading your advice, that's not a electric problem, but rather a shim issue that I can rebuild, right?

Thanks again.

Joel in Asheville, N.C.

Noah911

I think it is important to verify refrigerant level first, before removing a shim from the compressor clutch. The low side is easiest to check. I am not sure, but I think if the refrigerant psi is way off.. If that is the primary reason for why the compressor is turning itself off, then removing a shim from the compressor might turn the compressor on when it should really be off (to protect from damages to the a/c system). Low pressure switch would be the monitor to cycle, or turn the compressor off as a protective measure...

I would think for in your case if it was the switch seeing low psi turning off the compressor.. Then, it would stay off (or continually cycling) instead of responding to a nudge from a screwdriver.

It all sounds right to me.

Joel Burgess

Hey, Noah. I thought it was coolant, so I bought one of those recharge bottles with the hose and gauge. It told me I had plenty.

So, I started watching the compressor and noticed the clutch wasn't moving. Then I nudged it with a screwdriver and it spun. And stopped. And spun. And stopped. Which I think it's supposed to do - essentially, it's cycling.

But then it stopped. And didn't move.

I just wanted to rule out that it's an electrical problem. Doesn't seem like it to me. Seems like the shim issue you all have described.

Joel in Asheville, N.C.

Thanks again, all.

Noah911

Hi Joel!

It is called a compressor clutch air gap should you want to look it up to learn more about it.

The FSM has the range listed. It is 0.014" - 0.026" (0.35mm - 0.65mm). The ideal air gap would be set at 0.020"

With a simple measurment it sounds easy enough to check and verify. See if this is the probable reason for your compressor not functioning before removing or replacing shim(s) too.

Joel Burgess

Thanks, Noah. I'll check that out before going after a shim!