Summer heat causing random overheat with AC

incucrash · **Posted:** Tue Jul 03, 2012 11:23 am

2007 Liberty, 3.7L, 4x4, without heavy duty cooling system

I have just the single electric fan.

No overheating in winter, spring, or fall, a/c or not.

On days where it is 90+, I am having a random overheating issue

My fan comes on with ac button, spins nice and fast.

When I am going less then roughly 40, stopped, etc... The temp meter will start to float up, and to red if I do not stop it.

I switched relays with blower, no effect.

Coolant level full, and fresh.

A/c charged, but not as cold as it should be.

I been idling in shade for 20 mins, temp right below center, fan blowing hard.... Arghhhhh, frustration

My only guess is the extra heat is causing fan failure?

Any other sensors, stitches, relays to consider?

Has anyone done aux fans, if so, which and how?

I have caught the fan slowly spinning when this.happens.

Im replacing fan if no one elsr offers advice....

I

WolverineFW · **Posted:** Tue Jul 03, 2012 12:01 pm

When is the last time your A/C condensor was cleaned?

sota · **Joined:** Fri Aug 07, 2009 7:44 pm **Posts:** 379

clean the condenser and the radiator.
if that doesn't help you could have a bad thermostat or a failing radiator. neither part lasts forever.

incucrash · **Posted:** Tue Jul 03, 2012 8:29 pm

Ok, thanks

Why would the fan be running slow if shes running hot?

To add to my frustration; my compressor hissed out oil or something today...

smelled of deer urine, greenish looking.... I heard two loud hisses and saw a pool of oil behind compressor.

Fun

iamtheoldman · **Posted:** Wed Jul 04, 2012 4:06 pm

The green deer pee smelling stuff is R-134a A/C oil, commonly referred to as PAG oil. Wipe it of yourself and where it leaked, it can sometimes be nasty. Sounds like you may have an over pressurized A/C system, possibly due to overcharging but most likely due to inadequate air flow through the condenser (see previous posts). I've had the same problem and found a veritable graveyard of various fauna and miscellaneous debris on the condenser/radiator.
The slow cooling fan speed is problematic also and could be the fan itself or perhaps the ECM is not getting the correct info from one of the temp senders, (coolant and battery), engine speed or A/C switch position. I would suspect one of the temp senders. You may have to go through the test procedures in the manual. You can get a copy of the Factory Service Manual at various sites for various prices.

incucrash · **Posted:** Wed Jul 04, 2012 11:41 pm

Awesome info.

Thanks

Whats the battery sensor? I hope not ECM

A/C switch maybe, its something that malfunctions when its hot.

The compressor was probably over charged.

It did not seize, and I will not use it until it gets checked out.

It leaked, or.... Sprayed near back, I need to get all residue off.

I wonder if o rings are done, may be best in end to change compressor.

TwoBobsKJ · **Joined:** Fri May 11, 2012 8:03 pm **Posts:** 463

incucrash wrote:

Awesome info.

Whats the battery sensor? I hope not ECM

It sits under the battery and measures the battery temperature. If you remove the battery you'll see a plunger-like part - that's the battery sensor.

Bob

WolverineFW · **Posted:** Sat Jul 07, 2012 2:34 pm

incucrash wrote:

Awesome info.

Thanks

Whats the battery sensor? I hope not ECM

A/C switch maybe, its something that malfunctions when its hot.

The compressor was probably over charged.

It did not seize, and I will not use it until it gets checked out.

It leaked, or.... Sprayed near back, I need to get all residue off.

I wonder if o rings are done, may be best in end to change compressor.

If it sprayed out the back near the connections, then you have a leak, quite possible due to failed orings. Green oil is not a good sign, unless it is dye....if your system was serviced before, they may have put dye in it.

Problem with PAG oils is that it is hygroscopic and will turn green if it has absorbed a lot of moisture. Your whole system needs to be to have the charge pulled and leaked checked as well has having your compressor oil changed, dryer and orifice changed at a mimimum. If you have a lot of miles on the original compressor it may be worthwhile just to replace it outright since they will most likely have to pull it to drain the oil.

dieselenthusiast · **Posted:** Sun Jul 08, 2012 1:01 pm

Great info in this thread. Subscribing..........

incucrash · **Posted:** Fri Jul 13, 2012 2:08 pm

Took it in to dealership, they were unable to duplicate the problem, as am I...

Dealer notes: Could not duplicate problem, no DTCS in any modules, activated fan and checked wiring, no duplication.

it's only certain conditions...

the other day it was only around 80 degrees, raining, and I noticed my air, no a/c, just air begun to blow humid, and the needle was creeping above the half way mark, I was just coming from driving for about 30 minutes and parking....

It's 90% of the time when it is really hot outside, A/C running, however since my A/C sprayed, I have not used it, leaving the other 10% to random times with no a/c which is extremely rare...

Being that I caught the fan running slow one time, I think I will just start there and keep going, I hate to invest money in things that are not broke....

LibertyFever · **Posted:** Sun Jul 15, 2012 11:08 am

Okay let me see if I understand your problem. Your A/C operates well, cool air blows out the vents but when it gets hot outside and you need your A/C your engine is overheating. Am I right?

I've had experience with overheating in my 04 Liberty gasser but not with the A/C.

#1. Perhaps your radiator is plugged internally or the external fins are packed with bugs and dirt. I've had overheating issues before after a muddy trail run. A good wash with a garden hose cleared that problem. You can also flush the rad. Maybe the thermostat isn't opening.

#2. Perhaps your electric fan is only partially functional. It's a two speed fan and on my Libby I discovered the Hi speed was shot. Check the continuity of the electric fan with a VOM. The wiring to the fan is a three wire plug, Lo speed, Hi speed and a common line. If there is a problem with it sometimes you can get lucky and dismantle it and clean it too.

But I would assume that a dealership mechanic would have looked for all of these points. Maybe the dealership mechanic that looked at your Liberty wasn't too bright. It does happen.

incucrash · **Posted:** Tue Jul 17, 2012 2:11 pm

I ordered a fan, for now.

I popped hood and fan was spinning slow, but it usually works fine, both speeds

Something is causing fan to spin slow, if not the fan itself?

Figure its preventative maintainence, if it doesnt fix issue, I got a spare

I dont have time to play with dealers, troubleshooting, by the time I park jeep, wait for a tech, the problem is gone.
What else should I replace?

Im thinking its fan, relay, sensor related

The thermostat is fine, I sprayed out the fins on condensor, radiator.

dieselenthusiast · **Posted:** Wed Jul 18, 2012 12:31 am

If I were you, I would add a mechanical fan. Having both the mechanical and electric fan will make a huge difference.

jimymc · **Joined:** Thu Dec 17, 2009 7:51 pm **Posts:** 248

I had a similar problem to yours. The fan seemed to be intermittent and the engine would overheat when the AC was on and I was driving at slow speed. New fan fixed the problem. Now the fan really roars when the AC is on and the engine runs cool. AC units can do all kinds of crazy things when they are not getting enough air over the cooling coils. Hopefully, your new fan will fix the problem.

Summer heat causing random overheat with AC

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