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  #49  
Old 07-13-2012, 11:11 AM
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Re: Air conditioning thoughts?

Perhaps they tried tightening things down first, but I hear yah... not all shops are that competent... or chrysler has a directive to tighten things down first. My dodge front timing cover started leaking just enough to make the block wet at 65,000 miles (no noticeable oil use) and the dealer was glad to replace it under the 70,000 mile warrantee.

What gasket is seeping? About how many quarts per hundred miles is it currently leaking? Oil gaskets are not going to blow out unless its the oil filter gasket (or turbo oil supply we don't have on the gas GCs), usually because some grease monkey left the old gasket on. You should be checking oil level at each fill up anyway.

Sometimes the PCV valve or hoses are defective which allows the block to over pressure and force a little oil out at the weak gasket points, places where it would not leak normally. You could also have ring bypass issues that also would pressurize the block.

I guess this is getting off topic.. sorry
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  #50  
Old 07-18-2012, 01:20 PM
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Re: Air conditioning thoughts?

Hello all,

I am the engineer responsible for the climate control algorithms in both the manual (three knob) and automatic (one knob / LCD display) HVAC controllers in the WK2 (and new Durango and new Mini Van).

I cruise by the Jeep forums from time to time to get some valuable customer feedback on how good of a system the WK2 is in the customer’s eyes. I noticed that this community had a good discussion started regarding the overall performance of their HVAC systems so I thought this would be a unique opportunity to give my best answers to some of the questions.

Please note: I am not posting in affiliation or any other way with Chrysler LLC. The opinions expressed are that of my own and do not reflect the interests of Chrysler LLC.

Quote:
Originally Posted by MikeD View Post
I noticed on mine that when you take off from a light the A/C blower is reduced…
There is a vehicle speed compensation calculated into the blower speed. As the vehicle moves faster, more air is getting forced into the cabin due to “ram air” effect. To combat this effect, the blower speed is reduced as the vehicle speeds up. This is obviously only going to occur when the system is in FRESH and not RECIRC.

Quote:
Originally Posted by Technosavant View Post
I've found that somewhere between 68 and 71 degrees is generally preferred due to the sun shining in (whereas we might otherwise go for 74 or 75 degrees if we're setting a home thermostat).
We did all of our calibration and design studies with the temperature set to 72 degrees. This is the ideal target setting that is supposed to represent a majority of people's comfort level.


Quote:
Originally Posted by CIEGOS View Post
It is the best AC system I have owned, so far.
Thanks.


Quote:
Originally Posted by Bmwister View Post
Using the recirculate feature helps if you find yourself in slow/stopped traffic.
There is a rather complex algorithm that will automatically move the recric door at various rates / increments if the evaporator is not reaching its targeted temperature. Chances are, if the vehicle is stopped in traffic on a hot day, the air intake is moving (or has moved) towards recirc to help achieve better performance. Once the vehicle starts moving and air is again flowing across the condenser at high(er) speeds, the air inlet door will eventually go back to fresh.


Quote:
Originally Posted by jcnaranjo View Post
I just set a temperature (in auto) and let it do it's magic. Once the cabin starts to cool down, I press the recirculate button and the cabin stays comfortable through out my drive (moving or stopped)... No complaints here!
If the outside temperature is above ~85 degrees, it will likely start up in recirc from the get go assuming you are in AUTO.


Quote:
Originally Posted by wreckdive View Post
Very little cooling gets delivered to the rear seat passengers.
That is a known design concern. Usually though, the complaint is about heating performance in the winter as the floor ducts for the rear passengers are easily block when tall drivers / passengers slide the seat back too far.


Quote:
Originally Posted by jeep2011 View Post
Does anyone know what the temperature should be coming out of the vents? I would assume on LO it should be somewhere around 45 degrees.
It all depends on your driving conditions. If the vehicle is travelling at 60 mph down the highway in recirc at middle blower speed, you could probably even get down into the lower 40s. Standing still, it will be difficult to get much less than ~55 degrees on a hot day.


Quote:
Originally Posted by JayB View Post
With that we could tell if the system is designed on the smallish side or not and if the issues people are having are mostly control/software related.

Also we could see about potentially changing to a different expansion valve (assuming the systems uses a valve and not just capillary tube).
The 3.6L does indeed use a smaller compressor than the 5.7L engine… and yes, the system uses a thermal expansion valve buried DEEP inside the HVAC case.

Quote:
Originally Posted by OverlandGC View Post
My wife and I experienced weird AC issues this past 4th of july. We were making a 5 hour drive from DC to PA. Around the time when we hit the 3.5 hr mark, the AC started to die. I mean literally, fan speed lowered and got warm. You could hear the blower churning but no draft was coming out of the vents. This was on the manual setting at about 69-71 at full fan speed. Normally we wouldn't even need the fan on high at all. After shutting it off and running with the windows open we restarted the AC and it worked fine. This was on an 83* day. We then experienced the issue again and the jeep got terribly warm inside, we then used the Auto setting which we had not used before with the recirc option and it started to cool down.
EXCELLENT QUESTION! I’m glad you posted this. This is a textbook example of the evaporator “freezing up”. The control system is trying to drive the evaporator to the coldest possible temperature without causing the moisture in the air to collect and then eventually freeze up.

The targeted evaporator temperature in its lowest setting is 4 degrees C (39.2 deg F)

The worst case scenario for evap freeze is: high humidity, temperature setting in “LO”, running in fresh air, lowest blower setting. I spent hours, upon hours, upon hours in the wind tunnel adding various compensations to prevent this from happening. We obviously didn't capture every scenario, as there are multiple instances of evap freezing.

To prevent this from happening in the future, use AUTO and / or RECIRC on humid days. Leaving the temp in LO and setting the blower to a low setting is the worst thing a driver can do and will potentially cause an evap to freeze up.


Quote:
Originally Posted by JeepJunkie View Post
Also, a small GRIPE: Why do my aforementioned manual controls take like 6 seconds to engage once the car is started? Thats a hot 6 seconds I shouldnt have to wait! Most cars engage instantly.
It’s called “purge mode”. The function is twofold; it dries out the evaporator for six seconds and blows all that musty air out the floor ducts at minimum blower speedto prevent the customer from smelling it, and it also prevents “flash fog” from building on the windshield in the winter months. The purge mode should only be active if the car has been left alone for ten minutes or more.

I might check up on this thread once or twice, but I don’t plan on being a regular visitor.

Thanks for the feedback.

-B
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  #51  
Old 07-19-2012, 12:25 AM
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Re: Air conditioning thoughts?

wow...thanks for the feedback
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  #52  
Old 07-19-2012, 08:01 AM
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Re: Air conditioning thoughts?

How much smaller is the V6 compressor please, seems like an odd choice if everything else is the same. On another car I boosted the idle from 625 to 750 and radiator fan to HI if coolant over 180 to help with a/c at stoplights. Seems like simple programming.

BTW Orlando is about as hot/humid as you can get but have not seen an a/c freeze up for many years. Of course on other cars recirc is automagic if on max cool.
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  #53  
Old 07-19-2012, 09:57 AM
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Re: Air conditioning thoughts?

i find the AC to work rather well to be honest. even when my car is sitting in the NYC heat for 10+ hours, as soon as i start it, the vents are already blowing cold air. i love it
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  #54  
Old 07-19-2012, 02:23 PM
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Re: Air conditioning thoughts?

Any resolution on the AC not coming on with remote start?
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  #55  
Old 07-19-2012, 06:24 PM
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Re: Air conditioning thoughts?

I find it quite strong on mine.
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Old 07-22-2012, 06:14 AM
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Re: Air conditioning thoughts?

Mine still freezes up in Auto mode =(
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  #57  
Old 07-22-2012, 08:42 AM
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I find the AC in my WK2 SRT8 to work great in the New Mexico desert heat. I was experience some issues but I think it was due to my bwoody intake hitting the AC line running under it. It was transferring a lot of heat into the line. I put some insulating wrap around the line to keep it off the bwoody intake. Works like a charm now. I had one issue on a 30 hour drive when my AC froze up. It was running around 8 hours non stop in high 90's and very humid conditions. It seemed to work great until I shut it off briefly, then it froze up. Maybe 10-15 minutes later it was back to working order after letting it thaw and drain. With how much humidity the AC was removing from the air I know why it happened when I stop it. I've yet to have any other problems with it.


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  #58  
Old 07-23-2012, 07:07 AM
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Re: Air conditioning thoughts?

Quote:
Originally Posted by mofeen View Post
I have a three month old Overland. Now that it is getting warm here in Michigan, I have had a good chance to test the AC. Comparing it to WJ Overland that I am coming from, the AC is rather subpar. Just doesn't seem to blow very cold. Anyone else not impressed with the AC?

It is so-so, not perfect but OK. What is making me nuts is went which is blowing air to my face on any position I am turning it. One on right site from steering wheel. Hate this!!!
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  #59  
Old 07-23-2012, 10:39 AM
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Re: Air conditioning thoughts?

RE: Full-force air...

The assumption is that when the sensor determines the cabin is warmer/colder than the Auto setting, the system attempts to compensate (IE: move as much air as quickly as possible). I do agree it would be nice if you could adjust the fan speed manually without losing the Auto function, but then it would take longer to bring the interior temperature in-line with the Auto setting.

Just like a forced-air system in your home: Stand over the vent and you will get a high-speed blast of air. Stand a few feet away and you are comfortable. Problem is, you cant get out of the way of the air vents unless you are in the back seat....

I wonder, can you adjust the "open/close" wheel on the vent half-way in-between? I will have to test....
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Old 07-23-2012, 01:39 PM
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Re: Air conditioning thoughts?

Been having 100 degree plus days here almost everyday for the last 30-45 days. I just leave it on 71 all the time and it works perfectly. Even after it sits outside at work when I start it up it cools off real fast! I am 100% happy with it! Soooooo much better than the 2011 4Runner I dumped.
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