Hey Indy, gonna pick up the package this afternoon at FedEx. The way I tested the line was to turn on the a/c and feel which lines were cold. Those are the ones to wrap. Not being facetious, ya know?

 

I am just spitballing, and maybe getting a little off the wall here, but.....now remember spitballing, thinking out loud, outside the box whatever phrase that pays.


What I am thinking about is taking this insulation wrap to a WHOOE NOTHA LEVEL!!!!

We are doing all this insulation of the Front A/C but what about those of us that have the Rear A/C package? Yes wrap the insulation for the Rear A/C lines, does anyone have objections, or problems based on past experiences?

Anyone, anyone......bueller...hydra...mean.... kensai.....D408.... Southwestern US desert area.... anyone?

MAGIC

 

Ummmm.... I was under the impression that the back a/c was blown from the front motor unit?.....IE no refrigerant lines but insulated air ducts?...

 

FROM CHILTONS DAKOTA/DURANGO 2001-03 REPAIR MANUAL

PAGE 3-2.1 A/C SYSTEM:

" A rear air conditionning system is optional equipment on Durango models. This unit includes a separate roof-mounted evaporator core, blower motor and overhead controls. The rear air conditioning controls will only operate when the A/C mode is selected from the front A/C controls. Although the rear blower motor will operate independently to help circulate passener compartment air.

Separate roof-mounted evaporator core

I believe that the compressor works both but with a separate evap core, there must be an extension of the lines, probably downline of the forward evaparator. Anyone out there have any idea? maybe had the occasion of removing the rear evap core that can provide assistance?

Steve

 

Well you learn somwthing new every day! Now how would you wrap the line with foam? Wouldn't it be bigger than the space allotted for the unwrapped line? If/when you do it, we want pics!!!

 

It's the engine heat you are trying to cut down on. Cutting down on Cabin heat would be of little value because it doesn't get hot enough to affect metal in t Cabin (we hope)

IndyD

 

That is an interesting observation! I hadn't thought of it that way! Sounds like we have an answer to this. Thanks Indy!!

 

" A " all the way back and it looks like that includes " C "

Feel the lines all the way back and insulate the cool ones. Do this while the A/C is going to feel the cold lines. Wrap what you can because the rear doesn't pull enough but if you want to rip into the rear so be it but I wouldn't. Just do the ones you can see under the hood......IMHO

The " D " and " B " are hot lines that you DO NOT insulate.

 

I stopped by an automotive shop and bought a few feet of the "tar" tape. The mechanic asked why I was wrapping the lines and he said the tape wasn't for insulation but to contain leaks!? He recommended the plumbing pipe insulation and I asked if that would hold up under the heat. He said it wouldn't last for long. I asked about insulating the expansion valve and he said it needs the heat to operate properly? I didn't understand his logic, but then what do I know? Any thoughts or comments?

 

First, fire your mechanic, he does not know what he is talking about. Tar tape is not used to contain leaks, it does not have the tensil strength nor the adhesiveness to hold a leak if it busted. Tar tape is used to insulate the cold side of the refrigerant line to prevent sweating as well as provide some limited thermal insulation on the cold side.

Thermal expansion valves do not neccesary need insulation. The high pressure side of the freon is already pretty warm so it gets the heat from that. You only need to insulate the expansion valve to prevent sweating.

Brief summary of how a refrigerant system works: This appies to any freon based system. Autos, homes, refrigerators/freezers, etc....

Freon have a very low boiling point and have a proportional relationship when it comes to pressure and temperature. In lameman terms, if the pressure goes up, temperature goes up. Pressure drops, temperature drops. To keep freon in its liquid form, it must be held under a high pressure environment.

Example boiling points at sea level of commonly known freon:

R-12 = -22 degrees
R-134a = -15 degrees
R-22 = -41 degrees
R-410a = -55 degrees

R12 and 134a are commonly found in autos and refrigerators/freezers
R22 and 410a are commonly found in home A/C units.

134a and 410a are the new replacement freons for R12 and R22.

The expansion valve is the main player that restricts the flow of freon, thus changing its pressure/temperature ratio. Going from a cooled high pressure liquid to low pressure liquid changes the temperature from high temperature to low temperature. At low pressure, the liquid freon flows thru the cooling coil and and the temperature drops rapidly. As the heat is absorbed from cabin's hot air, the liquid freon starts to boil and converted to a gas. Then the low pressure gaseous freon flows to the compressor. Compressor changes the freon gas from low to high pressure. Again, pressure/temperature ratio is changed. Now temperature is changed from low to high. As the freon flows thru the condenser, the hot gaseous freon is cooled and condensed to liquid form. The high pressure cooled liquid freon enters the expansion valve. The cycles starts all over again.

A perfect example is when you buy one of those air duster cans for your computer, or if you ever play with C02 air guns, the can/cylinder starts to get cold as you release the pressure in the can. The High pressure liquid in the can starts to boil as it absorbs the heat around the can/cynlinder due to sudden drop in pressure.

Best to use a great thermal insulator like those found wrapped around copper pipes near the hot water heaters. But they won't last long under the extreme environments under the good. But they do have some polyeuthane type that will endure the stress.