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Insulating Vehicle A/C Lines #4785923
06/13/18 01:43 PM
06/13/18 01:43 PM
Joined: Aug 2017
Posts: 72
CA
ad244 Offline OP
ad244  Offline OP
Joined: Aug 2017
Posts: 72
CA
Since summer is upon us her ein the Northern Hemisphere, its A/C Season. Not saying the A/c system in my Tacoma is inferior and was charged last weekend but I was wondering if anybody on here has had any experience insulating the A/C lines under the hood?

I know in Home HVAC systems, the lines which run between the pump and the wall of the dwelling are oftentimes insulated perhaps keeping some of the cold lines "colder"? Since the cold lines run through the Hot engine compartment, would insulating the lines further help keep them cooler?

Re: Insulating Vehicle A/C Lines [Re: ad244] #4785931
06/13/18 01:55 PM
06/13/18 01:55 PM
Joined: Jul 2017
Posts: 101
GA
Pike51 Offline
Pike51  Offline
Joined: Jul 2017
Posts: 101
GA
It is not generally recommended. Info below taken from Stack Exchange because they explain it better than I can.

1. The cold side of the piping is after the evaporator, headed back to the compressor. Any loss here will not make a difference in the overall performance or efficiency of your AC unit.

2. Since the system is designed without the insulation, it may actually be detrimental to some of the working parts for it to be colder (may cause freezing of moving parts/evaporator). Engineers have taken all of this into account when designing the AC unit in the first place

3. Remember in order for condensation to form on this pipe it only has to meet two conditions: 1) pipe has to be cooler than the dew point; 2) there has to be humidity in the air. These conditions are very easily met in most situations.

Vehicle AC units are work pretty darn well considering what they have to do and the amount and quickness of cooling they have to do. Why mess with success. If you do, you could be introducing dynamics into the system they weren't designed for and you won't being doing much to improve the efficiency


1951 Chevy pickup 350/700r4
2015 Chevrolet Suburban LTZ 4x4
Re: Insulating Vehicle A/C Lines [Re: ad244] #4785936
06/13/18 02:13 PM
06/13/18 02:13 PM
Joined: Oct 2004
Posts: 8,054
Cincinnati, OH, USA
bullwinkle Offline
bullwinkle  Offline
Joined: Oct 2004
Posts: 8,054
Cincinnati, OH, USA
I would think there would be a risk of "slugging" the compressor with liquid refrigerant, likely damaging it. Unlike a hermetic or scroll A/C compressor, an automotive compressor can't take any liquid returning, at all.


06 Ram 3500 CTD 4X4(FG Venturi), 93 GMC C3500 6.2, 89 F-450 7.3, 98 XJ 4.0(XG8A), 05 xB(XG3600), 18 Transit 3.7, 03 Merc Grand Marquis 4.6 2V(XG2)
Re: Insulating Vehicle A/C Lines [Re: ad244] #4785937
06/13/18 02:14 PM
06/13/18 02:14 PM
Joined: Dec 2005
Posts: 9,998
Upper Midwest
kschachn Online content
kschachn  Online Content
Joined: Dec 2005
Posts: 9,998
Upper Midwest
Originally Posted By: ad244
I know in Home HVAC systems, the lines which run between the pump and the wall of the dwelling are oftentimes insulated perhaps keeping some of the cold lines "colder"? Since the cold lines run through the Hot engine compartment, would insulating the lines further help keep them cooler?

The "coldness" of the lines is immaterial for the most part. The smaller high pressure liquid line coming from the condenser is warm, you want it to reject heat if possible before it reaches the evaporator. The low pressure gas line from the evaporator to the compressor (the one that's insulated in your house and often in a car) really doesn't go that far and thermodynamically it won't make much difference when it comes to affecting the output temperature at the compressor. What insulation may already be on there is sufficient.


1994 BMW 530i, 231K
1996 Honda Accord, 263K
1999 Toyota Sienna, 402K
2000 Toyota ECHO, 272K
Re: Insulating Vehicle A/C Lines [Re: ad244] #4785964
06/13/18 03:01 PM
06/13/18 03:01 PM
Joined: Dec 2017
Posts: 1,140
US
JLTD Online shocked
JLTD  Online Shocked
Joined: Dec 2017
Posts: 1,140
US
On several of the Ford F150 sites, I've read where folks have insulated the cold side and increased the performance of the system, without any detrimental effects.


I'm a thickie; assimilate
But 20s have their place

Using AMSOIL

Hers: 2008 Jeep Liberty 138k, SS 5w30/Amsoil

His: 2015 4Runner 41k, OE 5w20/Wix

Re: Insulating Vehicle A/C Lines [Re: ad244] #4785969
06/13/18 03:11 PM
06/13/18 03:11 PM
Joined: Dec 2006
Posts: 7,761
Toronto, Canada
KrisZ Offline
KrisZ  Offline
Joined: Dec 2006
Posts: 7,761
Toronto, Canada
Lines in home HVAC systems are insulated, notice only the cold line is, so that condensation doesn't accumulate on the lines and start dripping inside the house. No such requirement for vehicles


2015 Dodge Grand Caravan-27k miles.
2006 Mazda 3-163k miles
Re: Insulating Vehicle A/C Lines [Re: ad244] #4785998
06/13/18 03:55 PM
06/13/18 03:55 PM
Joined: Apr 2008
Posts: 12,910
Onondaga County
Miller88 Online content
Miller88  Online Content
Joined: Apr 2008
Posts: 12,910
Onondaga County
Seems like it would promote rust under the insulation ...


18 Forester 2.5I 6M
00 Jeep Cherokee
01 Ford F-350 XL 4x4 5M
Re: Insulating Vehicle A/C Lines [Re: ad244] #4786010
06/13/18 04:08 PM
06/13/18 04:08 PM
Joined: Jun 2003
Posts: 17,475
Deplorable in apple valley, ca
Chris142 Offline
Chris142  Offline
Joined: Jun 2003
Posts: 17,475
Deplorable in apple valley, ca
Those trucks normally work well. Something is wrong with yours. Was it charged by weight or some yahoo with guages and a can? Is the heater valve shutting the water off to the heater completely? Bad compressor or expansion valve?


02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40
Re: Insulating Vehicle A/C Lines [Re: ad244] #4786020
06/13/18 04:24 PM
06/13/18 04:24 PM
Joined: Jan 2004
Posts: 4,243
California
nthach Offline
nthach  Offline
Joined: Jan 2004
Posts: 4,243
California
Mercedes used to insulate the AC lines in the 1980s-1990s with Armstrong Tubolit insulation, which I believe Armaflex at the local big box is the successor to that.

I don't think it'll hurt, if anything it might protect the hard lines from chafing.

Re: Insulating Vehicle A/C Lines [Re: ad244] #4786025
06/13/18 04:30 PM
06/13/18 04:30 PM
Joined: Dec 2011
Posts: 340
key largo,fl
henni Offline
henni  Offline
Joined: Dec 2011
Posts: 340
key largo,fl
One benefit to insulating a portion of the line from firewall (..only part of the line run...) is to stop condesate from the sweating line dripping onto belt(s) and slinging droplets all over. Would not otherwise care and system does not need it. On smaller Honda engines, this resulted in considerable difference in accumulating dirt on the sound insulation material under the hood.

Re: Insulating Vehicle A/C Lines [Re: nthach] #4786178
06/13/18 07:42 PM
06/13/18 07:42 PM
Joined: Dec 2002
Posts: 42,131
New Jersey
JHZR2 Offline
JHZR2  Offline
Joined: Dec 2002
Posts: 42,131
New Jersey
Originally Posted By: nthach
Mercedes used to insulate the AC lines in the 1980s-1990s with Armstrong Tubolit insulation, which I believe Armaflex at the local big box is the successor to that.

I don't think it'll hurt, if anything it might protect the hard lines from chafing.


I was just about to say this!

Re: Insulating Vehicle A/C Lines [Re: ad244] #4786179
06/13/18 07:44 PM
06/13/18 07:44 PM
Joined: Dec 2003
Posts: 9,843
Florida, Cape Coral
Eddie Offline
Eddie  Offline
Joined: Dec 2003
Posts: 9,843
Florida, Cape Coral
I bought pipe insulation from Home Depot and insulate the cold line in all my vehicles. On a 2007 Mazda I compared the un-insulated center vent out put temp vs insulated. The insulation helped the center vent temp by lowering the temp 2.5 F. measured with an accurate Digital thermometer. A worthwhile thing to do here in SW Florida. Ed


CX5 Touring 2.5L :-)
Re: Insulating Vehicle A/C Lines [Re: ad244] #4786228
06/13/18 08:34 PM
06/13/18 08:34 PM
Joined: May 2012
Posts: 1,401
Georgia
AVB Offline
AVB  Offline
Joined: May 2012
Posts: 1,401
Georgia
Chrysler actually started running a section of the high side line inside of the low side line. They decided cooling the high side was more important. They call it a internal heat exchanger.

Last edited by AVB; 06/13/18 08:39 PM.
Re: Insulating Vehicle A/C Lines [Re: Eddie] #4786230
06/13/18 08:37 PM
06/13/18 08:37 PM
Joined: Mar 2015
Posts: 5,092
Virginia
bbhero Offline
bbhero  Offline
Joined: Mar 2015
Posts: 5,092
Virginia
Great job Eddie. Very smart.


Nissan Altima 3.5 Coupe
Quaker State High Mileage 5w30 Purolator Boss 14610
"Treat your family like your friends and treat your friends like your family."
Re: Insulating Vehicle A/C Lines [Re: bullwinkle] #4786241
06/13/18 08:54 PM
06/13/18 08:54 PM
Joined: Jul 2013
Posts: 1,751
Ottumwa, Iowa
jhellwig Offline
jhellwig  Offline
Joined: Jul 2013
Posts: 1,751
Ottumwa, Iowa
Originally Posted By: bullwinkle
I would think there would be a risk of "slugging" the compressor with liquid refrigerant, likely damaging it. Unlike a hermetic or scroll A/C compressor, an automotive compressor can't take any liquid returning, at all.


Considering the fact that oil and liquid refrigerant are added to the return line that is impossible.


The dryer/accumulator on my 95 Suburban was insulated from the factory.



On a side note I blew the thrust bearing out of a 2000hp turbin compressor chiller when I restarted it without water flow through the evaporator. The tech had recommissioned it but not run it but left the compressor thrusted out of center. He told me how to reset it over the phone but didnt remember that the valve was closed on the chilled water return till it went bang. So you can get the systems to cold.

Last edited by jhellwig; 06/13/18 09:03 PM.

Sparks fly from my fingers.

1995 Chevy K2500 Suburban lt 5.7
2014 Toyota Sienna
1983 Chevy K5 350
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