A/C upgrade????

[goodguys75]

I live in vegas and it is hot. The a/c in my 06 mega cab is horrible, it does not cool to well. My wifes tahoe will freeze you out... anyone else have this problem. . Its not a faulty a/c unit, the dealer told me it is within there specs... just want to know if we can do anything about it... . #@$%!

 

[Crunch]

I live in vegas and it is hot. The a/c in my 06 mega cab is horrible, it does not cool to well. My wifes tahoe will freeze you out... anyone else have this problem. . Its not a faulty a/c unit, the dealer told me it is within there specs... just want to know if we can do anything about it... . #@$%!

Did you buy the truck new on `06, or used recently? You might want to spend the ~$50. 00 to have someone check the A/C pressures. I think the pressure should be 45 on the low side on a 100* day. But if you have even a small leak they won't recharge it until it gets fixed. Another option is to go to Walmart and buy the simple pressure tester/dispenser device for $16. 95 and check it yourself. If you go this route and need to buy some R134a make sure you get the stuff that has no leak sealant or any other additives in it. And don't overcharge your system. High pressure and hot days are a bad combination for air conditioners. Within specs for the dealer doesn't necessarily mean it's in optimal performing condition.

 

[sabersix]

Megas do not cool well. This has been discussed at length. Folks have tried numerous "fixes", but what it comes down to is there is too much volume in the cab to cool down quickly (if ever).

I have my front side windows tinted and use a windshield sunscreen during the summer. This will help keep the interior temps lower so your A/C system can cool off faster.

That said, I'd also do as Crunch recommends and get the system checked to verify correct operation.

 

[SFPADGETT]

What my friend found, was that if he cracked one of back windows, (Along with the tinting) the cab cooled MUCH better and faster. It seems that with the windows up the pressure in the cab gets to the "positive" side and the AC blower will not force as much volume of cool air into the cab. He found this out when flying a college football penant off the back windows, which created a small gap at the top--1/8" or less, if also creates a negative pressure area by the window that sucks out the air near the ceiling (hot air rises)

 

[tkerrigan]

Some people are bypassing the heater core coolant hoses using valves, you get much more cooling that way, but loose the ability to adjust the temperature of the air. In LV, this time of year, no problem.

 

[Bob4x4]

A cab that big would benefit from another condensor in the rear ala Suburban.

 

[tempforce]

one other option is to convert the system to use a better coolant.

you would have to have the system checked for leaks. pumped down to a 29" and held for at least a 1/2 hour. rechecked. if holding a 29" negative pressure. charge it with one of these.

Environmentally Friendly Hydrocarbon Refrigerants HC-12a, HC-22a and HC-502a from Bennett Cycle & Supply

Duracool®.com 2004 - Duracool® is The Recognized Leader In Hydrocarbon Refrigerant Technology

freeze 12 r12,FREEZE12 COMPATIBLE R12 REPLACEMENT A/C REFRIGERANT

your high side pressures will be lower so the compresser will last longer.

you should get 10-20% or better, cooling.

 

[Bob4x4]

After reading their website it looks like it is the Cats meow... ... ... . why are the OEM. s not using it??

 

[Bob4x4]

On the Mega cab there is also a nylon screen that lessons the airflow to the rear. Roll the dash back and you can cut it out... ... ..... cost,free

 

[Crunch]

Megas do not cool well. This has been discussed at length. Folks have tried numerous "fixes", but what it comes down to is there is too much volume in the cab to cool down quickly

Too bad they don't make an A/C spritzer for vehicle A/Cs like they do for the home units. I bet one of those would go a long way toward better cooling.

 

[rscurtis]

I often wondered how R12 would work in this system. If I ever have to go into my system, I may try it, as I have plenty in stock for the old Mercedes.

 

[Crunch]

I often wondered how R12 would work in this system. If I ever have to go into my system, I may try it, as I have plenty in stock for the old Mercedes.

Here's a link to a thread where that question was asked, and the idea of using propane came up!

But I'm kind of intrigued by the liquid nitrogen idea...

 

[lil red cummins]

Afrias:



there have been a couple of good suggestions made so far.



1. crack the rear windows 1/2" or so



2. block off or clamp off the heater hoses



both are good and NAPA and other auto parts stores sell a tool made by KD that is a locking clamp with flat blades designed for emergency hose shut off. they work well.



3. Not mentioned, keep the system in the "Recirculation" mode. this will keep cooling the same cab air, rather than bringing in fresh HOT air.



i have a big concern however with changing refrigerants.



R134a works well at the right charge load and changing to other types should be done with caution as there may be system incompatibilities with the different types



Not all Freon products are designed to work at the pressures used in automotive applications.



R12 & R134 are for automotive use and are designed to work in the 28-32 PSI (low side) pressure range and 250-400 PSI (high side).



Changing BACK to R12 could cause problems because of oil and seal incompatibilities. Not to mention cost and availability. there are newer freons, but read carefully about what they are replacements FOR.



The biggest cause of weak cooling is due to under charging or over charging of the freon.



You really need to put a set of gauges on the system and look at the operating pressures. They vary widely due to engine RPM, humidity, blower speed and temperature.



there is also a direct and consistent pressure/temperature relationship with freon. the gauge pressure should tell you what the freon temperature is and this can be monitored with a probe thermometer stuck in the cooling outlets.



with the blower speed on low, you should be able to get the compressor to cycle on and off regardless of temperature. you may have to raise engine speed above idle, but it should happen. compressor shutoff should occur as pressure drops to approximately 24 to 28 psi and turn back on around 40 psi.



with the blower on high, it is less likely the compressor will shut off even with the engine at 2000 RPM, especially in 90 degrees. you can expect high side pressures to reach 400 psi or higher.



the key to knowing whether or not the system is charged correctly is to obtain a temperature/pressure chart available for automotive air conditioning.

this is all about the pressure reading on the high side.



if your compressor does not cycle on low blower speed, even with raised engine speed, it may be over charged.



if the compressor cycles too often on high blower speed, it may be under charged.



Very slight under charging will give you cooler air temps but may take a little longer to get cool from initial startup.



putting a probe type digital thermometer in the cooling vents tells you a lot about how efficient the system is. Measured temperature should be within 10 degrees of what the gauge says for any observed pressure on the low side.



Lastly, whether you have an automatic or stick, when you first start a hot vehicle, shift down and keep RPM's up to get the compressor turning faster.

i am not recommending max RPM, rather, try and hover around 2000 RPM.



i have been repairing and upgrading R12/R134a systems for 30 years or so.



And yes, it is very possible that the Dodge engineers undersized the system for your truck and there aren't many options for that.



Hope some of this helps.



Jim

 

[goodguys75]

i think this is the problem, to big of a truck too cool. A/C is working fine and within specs of the manufaturer... . I think if they ran gm compresors they would cool a lot beter. . chevy has a kick *** a/c system... all good input, thanks alot

 

[goodguys75]

most of you guys live in a lot cooler climates... today the high was 113* and the a/c can barley keep up in city trafic. . on the highway it does way better... ... . great testing grounds for any vehicle... lol

 

[tempforce]

chrysler needed to install a larger condenser and add a second evaporator for the rear.

 

[monkeyman]

Its not just the temp but humidity level. Its in the 90's here with 60+ humidity, that is hotter than 113 with low humidity. I have no problems with AC with tinted windows and recirc mode.
Rick

 

[Axekicker]

I live in vegas and it is hot. The a/c in my 06 mega cab is horrible, it does not cool to well... ! (edited)

Yep... me to. Take a ride with me in my '04. 5 sometime... I did an all-day building inspection up on Whitney Mesa (Henderson) last week... got into my truck at 5:30pm and the overhead read 120-degrees. Within a couple of miles my A/C had frost on my mustache.



When I got my truck new (Sept. '04) the A/C worked poorly in the summer when it got over 100-degrees. I took it to Fabulous Freddy's in Summerlin and when they put it on the 'machine' it was wwwaaayyyyy overcharged. When the A/C machine high-side dial-indicator went over 450psi and kept climbing, the tech shut it off and advised me to evac the system and recharge it... which we did on-the-spot. Prior to that, the A/C had never been touched. It came over-charged from Dodge.



As he was re-charging he told me about ICE-32 (an A/C additive) and gave me a brochure to read. The product was about $65. 00 for a 1. 5 oz bottle, which is not-cheap... but it promised to lower A/C 'supply' temps etc... so I pulled out my contact-thermometer (that I use to check residential & commercial A/C temp-drops at the B-coil(s) when I'm doing building inspections) and shoved it in the drivers side supply vent and had him add the can of ICE-32 while I kept an eye on the thermometer. I watched the temps drop from 49-degrees to 38-degrees as the contents of the can went in. Amazing!Oo. That was 2005.



I just had my compressor, pressure transducer and some other A/C parts replaced at Auto Air & More Inc. @ 4295 W. Tropicana and they put in another 1. 5 oz bottle of ICE-32 and Bam! Ice-Cold... . as before! If you want to take a ride with me and see how well it works... even on the hottest day in Vegas... let me know. Then head over to Auto-Air and have them set you up. Top-notch shop, great-crew, superior customer service and did I say fast? Took my truck in at 11:00am and drove back to work at 12:45pm. I recommend them and the ICE-32 product... . after 5 years of using the product, I'm a big-fan.

 

[BGlidewell]

Yep... me to. Take a ride with me in my '04. 5 sometime... I did an all-day building inspection up on Whitney Mesa (Henderson) last week... got into my truck at 5:30pm and the overhead read 120-degrees. Within a couple of miles my A/C had frost on my mustache.



When I got my truck new (Sept. '04) the A/C worked poorly in the summer when it got over 100-degrees. I took it to Fabulous Freddy's in Summerlin and when they put it on the 'machine' it was wwwaaayyyyy overcharged. When the A/C machine high-side dial-indicator went over 450psi and kept climbing, the tech shut it off and advised me to evac the system and recharge it... which we did on-the-spot. Prior to that, the A/C had never been touched. It came over-charged from Dodge.



As he was re-charging he told me about ICE-32 (an A/C additive) and gave me a brochure to read. The product was about $65. 00 for a 1. 5 oz bottle, which is not-cheap... but it promised to lower A/C 'supply' temps etc... so I pulled out my contact-thermometer (that I use to check residential & commercial A/C temp-drops at the B-coil(s) when I'm doing building inspections) and shoved it in the drivers side supply vent and had him add the can of ICE-32 while I kept an eye on the thermometer. I watched the temps drop from 49-degrees to 38-degrees as the contents of the can went in. Amazing!Oo. That was 2005.



I just had my compressor, pressure transducer and some other A/C parts replaced at Auto Air & More Inc. @ 4295 W. Tropicana and they put in another 1. 5 oz bottle of ICE-32 and Bam! Ice-Cold... . as before! If you want to take a ride with me and see how well it works... even on the hottest day in Vegas... let me know. Then head over to Auto-Air and have them set you up. Top-notch shop, great-crew, superior customer service and did I say fast? Took my truck in at 11:00am and drove back to work at 12:45pm. I recommend them and the ICE-32 product... . after 5 years of using the product, I'm a big-fan.

that sounds pretty good! Thanks for the info.

 

[ringneck]

tint front and side windows,keeps sun ultra rays out. you want feel hot and cold at same time. I had a light film put on front and sides,cops cant tell. 05 dually.