This one's for any A/C experts. Was noticing that one of the lines on my A/C (return line? see pic) was real cold, even icy, but was exposed to a lot of heat once the engine was warmed up, and part of the line was insulated or in rubber hose, but part of it was exposed. Noticing that the line on my home's A/C had this insulation foam on, I figured it couldn't hurt ot try and keep this line a little cooler so I installed some foam and wrapped it in metallic tape (see pic below) to try and keep this line as cool as possible.


Then I got to thinking (big mistake) - if GM didn't see fit to better insulate this line, was there a reason for this, like maybe the line needs to "sweat" - or is this just another case of GM shaving a few bucks off like they did by removing all the interior lighting?


I also noticed that on the other A/C line that's near the aux battery, which appears to be coming from a radiator up front, the line was hot up to a fill tap, and then cold. That one really threw me because I don't see how an inline tap could modify the temperature of the line, but the line is literally hot before the tap, and cold after it - see the pic below. Anyone know why this is?


Thanks guys.


http://www.dieselplace.com/forum/uploads/33F_IMG_4001.jpg


http://www.dieselplace.com/forum/uploads/CCC_IMG_3996.jpg

The line is exposed to make sure that no liquid or unexpanded gas makes it to compressor. The resason for the temp change it that you must be looking at were the expansion valve or orafice tube is located inside pipe and there will be a big temp change across it.

The expansion valve is the change between low pressure and high pressure in the system thus the change in heat diffierences.

So then are you guys saying it's a GOOD THING or a BAD THING that I've insulated this line? I'm thinking my picture wasn't clear enough so here's a better shot.


http://www.dieselplace.com/forum/uploads/9DB_IMG_3997.JPG

If you live in a very hot area it may not be a bad idea but generally you do not want it insulated between accumulator and compressor on low side in a vehical. Live it on for now and see if A/C works any better overall.

I was told that GM removes more and more items from undr the hood to save pennies in cost http://www.dieselplace.com/forum/smileys/Cry.gif


I have also been informed that insulating this line will help AC. i plan on doing it soon! AC sux unless you are moving. I do a lot of desert driving in the summer at slow speeds so I need all the cool air I can get.





On my old 1500 gasser I have electric fans which worked great at slow speeds keeping it ice cold inside the cab. Towing with e-fans is not a good thing http://www.dieselplace.com/forum/smileys/Cry.gif


I have been trying to think of a way to add a couple small fans on the front of the radiator for these slow diriving conditions and still be able to have the stock fan for towing etc etc.

I was told that GM removes more and more items from undr the hood to save pennies in cost http://www.dieselplace.com/forum/smileys/Cry.gif


I have also been informed that insulating this line will help AC. i plan on doing it soon! AC sux unless you are moving. I do a lot of desert driving in the summer at slow speeds so I need all the cool air I can get.





On my old 1500 gasser I have electric fans which worked great at slow speeds keeping it ice cold inside the cab. Towing with e-fans is not a good thing http://www.dieselplace.com/forum/smileys/Cry.gif


I have been trying to think of a way to add a couple small fans on the front of the radiator for these slow diriving conditions and still be able to have the stock fan for towing etc etc.


E-fans are not the end all solution that some think they are huh? You might try a different clutch fan and blade on your engine. My 2000 K3500 has HD cooling and a 10 bladed clutch fan and the temp never rises even in traffic and AC stays cool too. It is not very loud either and overall it is quieter than the one on my 89 4x4 burb with factory HD cooling.

HD cooling?


Which fan do you suggest?


How many blades is a stock fan?

HD cooling?


Which fan do you suggest?


How many blades is a stock fan?

I am not sure what is "stock" but mine has 10 blades on it from factory (the most I have ever seen anyway) Check and see what parts they list for a 2000 K3500 with a 5.7 for fan and clutch as mine never breaks a sweat no matter what I do. Edited by: snoman

I'm not saying the stock fan breaks a sweat. i am satying it does not cool as well as when you are moving over abour 30 mph.





With e-fans is pulls air through and doesn't rob tons of HP.

I'm not saying the stock fan breaks a sweat. i am satying it does not cool as well as when you are moving over abour 30 mph.





With e-fans is pulls air through and doesn't rob tons of HP.







I do not have that problem with my K3500, temp gage never moves at idles or speed, load or not even on hottest days. Sometimes you can here the fan starting to come in going down the road but it it not very noticable. On my 89 burb it recently started to get a bit warm on the road before fan would come in on a long hill climb (between 200 and 210). The took clutch off and tweaked the bimetal coil a tiny bit and the problem went away and you can here it dropping in and out on a hot day too.(more audible than K3500 but not excessive) If you cannot hear it, then you are not moving enough air on a hot day.

Dduffy,


Did the insulation make any difference?? Is it cooler now???


Let us know.


Thanks,


Marco Polo

Dduffy,


Did the insulation make any difference?? Is it cooler now???


Let us know.







Good timing. I just came back from a 3-state, 3,000 mile trip and can report no problems. Weather varied from 90-100+ and the A/C was on the entire time and always delivered.


However, I'm not sure that the insulation made that much difference. Maybe in my mind it did, but even if that's all, I just prefer to try and eke every bit of performance I can from the truck so I'm happy with it. As long as I know that it doesn't do anything to adversely affect performance, it seems like a no-brainer for a few bucks in insulation and tape.

Dduffy, your idea about the insulation might be getting close to part of the problem. I had the stuff on the TSB done to my pickup today. The new hose they put on has a heat shield on it right above the turbo. Not sure if the work they done is going to help or not, it was only in the low 70's here today.

It looks to me as if you have added insulation to the suction (low) side of the refridgerant connection running from the bottom of the accumulator to the compressor. IMHO, this is completely unnessescary & although I believe it shouldn't do any harm, it certainly won't do any good. What I mean is, one way a/c operates is by the regulation of pressure, & as the laws of physics state, pressure & tempurature are relative, by increasing (or decreasing) one, you increase (or decrease) the other, so by raising & lowering pressures, we raise & lower tempuratures, & visa versa. This (& the following) are basic a/c principles of operation (they do not take into consideration humidity control - which is a HUGE part of 'comfort' control - or heat transfer rates via fan speed), but this is a crash course, so....


The compressor compresses gas (refridgerant) into a liquid (via the condensor), this is transported (under high pressure/tempurature) to an expansion valve located close to the cab, this valve (thru restriction) reduces the pressure/tempurature as the refridgerant passes thru the evaporator (a radiator of sorts) in the cab, a fan blows air over this cooled radiator cooling the interior of the cab (technically, it is really transfering heat from the air in the cab to the refridgerant), the low pressure/temp refridgerant exits the cab to the accumulator (which primarily aids in bleeding off any refrigderant that remained in a liquid state upon leaving the evapoator, as most vehicle compressors don't react well when attempting to compress liquids). This gaseous refridgerant is 'sucked' into the compressor where it is compressed to a pressure just below the point it would convert to a liquid (remember, compressors don't react well to liquids), this high pressure/temp refridgerant is sent/discharged to the condensor (the a/c radiator in front of the coolant radiator in most vehicles), where with the help of nature (ie-air flow cooler than itself over the condensor/radiator), it is condensed (hence the term condensor) into a liquid, meets the expansion valve, which allows it to expand (ie-reduce in pressure/temp), cooling the evapoator, etc, etc, etc..... (this is a continual process)


By putting insulation anywhere in the system where it is not intended, you upset the natural processes engineers may have allowed for this particular system (not to say engineers are perfect, but..). Here it seems it would be the ability of the heat in the engine compartment to contribute to the proper/effective conversion of any liquid refridgerant to a gas (via thermal expansion) before it reaches the a/c compressor, preventing the possibility of 'hydraulic lock' causing any compressor damage.


Now I'm not saying this particular mod will reek havoc on your a/c system, but unless the benefit is obvious (& I don't see how that mod is), why give any opportunity to deny a warranty claim should one arise? http://dieselplace.com/forum/smileys/Dead.gif


Hope this helps provide a better understanding for anyone who may be interested (it is just a really simplified explaination of an a/c system though)

i looked at my 01 sonoma and the line coming from the compressor to the acumulator is INSULATED..! so i went and insulated the same line on my dmax...if it only cools it down one more degree... i'll take it..and am not stopping looking forways to improve cooling cap...i am leaking warmer air in my drivers vents than on passenger side...will begin working on this one next...later bchttp://www.dieselplace.com/forum/smileys/smiley5.gif

The insulation that was on the new hose on my pickup was over the turbo heat shield. I added circled were mine is on the picture below. It is the same picture Dduffy posted I just put a red place were mine is.
http://www.dieselplace.com/forum/uploads/BIGMoe/2004-10-03_210807_moesdmax.jpgEdited by: BIGMoe

Update - I pulled the insulation off after reading the input on this thread. Never noticed a difference either way. It made me THINK I *might* be colder but based on some good input above, I took it off. Hopefully the people in Detroit knew more about A/C than me and left it off for a reason - not just to be cheap.