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Jeep green oil splatter with pics

ariff on Wed May 12, 2010 8:28 PM User is offline

Year: 2001
Make: Jeep
Model: Cherokee
Engine Size: 4.0

Hey guys,
I have been trying to track down a problem with my AC. It will seem to work just fine and it is nice and cold. Then every once in awhile I'll hear a short grinding sound. It lasts no longer than a second. The AC still works and it is still nice and cold. However when I look under the hood I see the green PAC oil from the compressor splattered all over my firewall and hoses. As you can see in my pictures it looks like it is shooting from a hole on the back of the compressor. Any ideas what might be causing this problem? I am a total Newbee at AC systems. This is the first system I have ever had issues with on any of my cars. So talk to me like I am 5 years old ;>) I don't have any tools or gauges for a pressure reading.
Thanks guys!

Rear shot of Compressor. Is this a pressure relief valve that the oil could be coming out of?

GM Tech on Wed May 12, 2010 8:51 PM User is offline

Classic high pressure situation- usually there is a high pressure cut-off switch to turn off the compressor- but evidently yours is inop- orthe pressure builds up too fast to activate it, or the switch is downstream of the restriction. Number one thought-- is your cooling fan working properly?- clutch fans can be nightmares for a/c-- they can be sluggish, delayed response, or just worn out- the condenser needs the airflow across it- even when radiator is cold-- test your clutch fan- replace if necessary. If you have an electric auxiallary fan- check it out as well.....

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

ariff on Thu May 13, 2010 1:08 AM User is offline

Thanks for the reply.. I checked the fan clutch with engine off but at operating temp. It will only turn about half a revolution when spun by hand. So sounds like the clutch is ok. I can also hear the fan come on and off while the clutch on the compressor is engaging. Anything else I can do to troubleshoot the problem. Could have the previous owner put to much refrigerant is in the system? I do know he filled it up himself when her replaced the compressor. My Father in law checked the pressure on the low side with his simple gauges and it was in the red zone with the car off, but with the car running it was right at the beginning of the red zone. There were no numbers on his gauges.

Chick on Thu May 13, 2010 7:19 AM User is offlineView users profile

You need real pressures, not the one gauge kind..But I would suggest having the system evacuated and recharged properly. then you can check the pressures.. Sounds like it may have been filled with a death kit leaving air in the system..But only knowing that is is charged properly is going to tell..

Email: Chick


Freedoms just another word for nothing left to lose

ariff on Thu May 13, 2010 9:22 AM User is offline

What the heck is a Death kit? :>)
Looks like I'll take her by the shop and have them evacuate and fill the system again.

Edited: Thu May 13, 2010 at 9:24 AM by ariff

ice-n-tropics on Thu May 13, 2010 11:48 AM User is offline

a riff,
Can see your high pressure switch just 4 " farther down the refrigerant flow stream from the Pressure Relief valve (PRV).
Sanden comp is shown. Sanden PRV spec is relief spray out at 450 +/- 50 psi. Once it blows off just one time then subsequent pop offs will be at lower pressure because tiny particles lodge on the rubber seat. Therefore you may need a fresh PRV.
High Pressure cut out electrical switch (HPCOS) shown on discharge line spec is 475 or 490 psi +/- 15 psi.
One other factor is the tiny orifice (4.7 mm) in the compressor discharge port which Sanden thinks makes the comp quiet. This unnecessarily raises the pressure on the PRV (before orifice) much higher than the HPCOS (after orifice). It may be necessary to drill out the orifice to 1/4" or larger.
You need to replace the oil which blew out together with the green dye.

Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

Edited: Thu May 13, 2010 at 11:49 AM by ice-n-tropics

ariff on Thu May 13, 2010 3:17 PM User is offline

Thanks for the reply.. Man I am having a hard time making sense out of your reply though. I am sure to someone who knew the in's and out's of auto A\C systems it probably makes perfect sense. I am thinking on this one I might just bite the bullet and take it in to my mechanic. I really like to do most of the work on my vehicles myself, but I know when I am in over my head. My plan now is to have them evacuate the the A\C system and recharge it to the correct spec. Replace the oil that has been sprayed out and generally check out the A\C system. Does this sound like a good plan?

ice-n-tropics on Thu May 13, 2010 4:03 PM User is offline

My explanation is more detail, but agrees entirely with GMTech.
The green oil and refrigerant is blowing out of the PRV when the pressure at the PRV is greater than the PRV internal spring force and before the clutch cycles off due to overpressure at the 3 wire HPCOS connected 4" away the compressor on the discharge line.
Sure, get the system repaired.

Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

iceman2555 on Thu May 13, 2010 11:59 PM User is offlineView users profile

By all means follow the info supplied by GM and 'ice', however,since the fan only turns a short distance when engine is shut down does not mean the fan clutch is truly operational. The fact that one can hear the fan does not add additional information to supplement this assumption.
Suggest to repair the PRV and have the system evac and recharged correctly. Test pressures but also perform valid fan clutch test. Considering the age of the vehicle, possible mileage, the fan clutch is high suspicious.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

ariff on Fri May 14, 2010 9:37 AM User is offline

Thanks for all the replies and tips.. I have an appointment on Tuesday to have my mechanic take a look at it. Worse case scenerio I'll have him evacuate the system and I'll replace the copmpressor, Dryer, o-rings and Oriface tube. Any suggestion how to properly test the fan clutch?

Edited: Fri May 14, 2010 at 9:39 AM by ariff

ice-n-tropics on Fri May 14, 2010 1:02 PM User is offline

a riff
As one of Tim's Band of Brothers, I have never even hinted that you should throw your money down a rat hole by replacing the compressor. No other brothers here have given you that idea. We are not "parts changers".
Your compressor pumps great. Keep it.
Consider to send 10% of your savings to Samaritan's Purse.

Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

ariff on Fri May 14, 2010 3:27 PM User is offline

Oh I hear ya loud and clear as I am not one to drop money on replacing parts that don't need replaced. I was saying this is worse case scenerio for me. If that were true I'd replace the stuff myself. As for the donations.. We have donated several times through our church to Haiti. Thanks again for all the help I have learned much from everyone in the last few days. Still no pro by any means. But at least I have a pretty good idea what is going on. Hopefully this will help me out if the mechanic tries to pull a fast one on me.

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