Ac blows hot until moving in my 2013 legacy premium

[Picky1]

So I hit up Home Depot and bought some insulation. I splurged and spent twice as much, $4.50, to get the nicer looking rubberized stuff so we'll see how it handles the heat. Looking at where it will be it won't be very near any super hot parts, such as exhaust, so I would be more worried that it would melt and/or smell bad. But it that is the case then surely that heat is bleeding into the AC system.

I only intend to wrap any cold parts: between the compressor and the firewall on the warm part of the low pressure side; and between the expansion valve and the firewall if that part is exposed. I figure that could help decrease heat soak at idle or low speeds.

 

Be sure to post pictures when you are done...thanks!

[YeuEmMaiMai]

Compressor size and refrigerant volume aren't going to change cooling performance that drastically, it just means the compressor might not have to run at as high a duty cycle. If you want to actually make a good comparison between the two (which "X doesn't suck" is not, by the way), you're going to need to look at the heat exchangers. You can cool effectively with a lower volume of refrigerant if you get enough performance out of the condenser and evaporator.

 

If you want my semi-educated guess, the condenser on your '03 is probably larger than what's on the 5th-gen, which allows it to perform a little better in high ambient temps with no airflow (idle warm-up), at least until it gets heat-soaked. Putting a fan on the condenser would probably help a bunch if the radiator fans aren't running.

 

yes, it will... larger system and more refrigerant = better performance... and sufficient reserves capacity

[Aces36]

I was in kind of a hurry when I did this so it is not as neat as I would like it to be. I wanted to see if it worked and figured if it did work I would tidy it up a bit in the future. The more important hose to cover seems to be the one going to the firewall. It passes within 1/2" of some hot engine parts.

 

http://i413.photobucket.com/albums/pp217/sts-v/C08F3AAF-6FDF-4393-87C0-78F0688A31A2_zpsmlnx0vti.jpg

http://i413.photobucket.com/albums/pp217/sts-v/B82CD4CE-E0D8-438A-8BE5-4679478F91DC_zpsizc6tcxa.jpg

http://i413.photobucket.com/albums/pp217/sts-v/27BA55F5-0E39-4840-AD99-0659E6916C50_zpsgovyok4g.jpg

http://i413.photobucket.com/albums/pp217/sts-v/E04BE22C-BE5C-446E-A5E1-14D2517F5A58_zpsxipxlf1f.jpg

 

http://i413.photobucket.com/albums/pp217/sts-v/3986A082-D67F-4E5E-A025-001B03E11C2C_zpsjvhbtt3u.jpg

http://i413.photobucket.com/albums/pp217/sts-v/43029B70-410D-4422-8443-DE2A646F59D6_zpsmmgrttsj.jpg

http://i413.photobucket.com/albums/pp217/sts-v/687E5E72-9855-4E01-99DB-9DC153800854_zpst4ogwxcj.jpg

[Aces36]

I have also been thinking about doing this. My concerns:

1. any negative affect to the AC system?

2. Fire/heat rating of the insulation

3. I would be willing to pay a few more dollars for an automotive/heat-rated product if anyone has any ideas or links?

 

thanks

 

I have had it like this for a few months now and nothing is melted nor have I smelled anything melting. I don't know what the heat rating is on the foam but if you could find fiberglass pipe insulation that isn't wrapped in paper then there would be no worries of it catching on fire. As far as a negative effect, nothing yet.

[cww516]

yes, it will... larger system and more refrigerant = better performance... and sufficient reserves capacity

 

That's not really how refrigeration works- the cooling happens when the liquid refrigerant evaporates (latent heat of vaporization), and is rejected as it condenses (latent heat of condensation). You're not really cooling the liquid refrigerant in the same way as you cool, say, engine coolant (you do a little when it's in the condenser, I suppose), you're compressing and cooling a gas until it turns back into a liquid. How much extra liquid volume you design int the system isn't going to affect system performance, although it might affect compressor duty cycle, it's just extra. You'll get better performance at the extremes (high ambient temperatures, which is where heat pumps are least efficient) out of a larger condenser (more surface area = more heat transfer, all others being equal), but 99% of the time, you'll just have overdesigned and/or mismatched heat exchangers that hold way more refrigerant than you really need. Extra margin equals extra price and extra refrigerant that could end up vented to the atmosphere.

 

tl;dr- you'd have to make everything bigger, adding more refrigerant alone won't change anything.

[Sarang]

Prior to this first pic I removed my tmic and purchased 6 feet of .5" pipe insulation from Home Depot.

 

This is where I started

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11417

 

Second pic is of the insulation on the pipe. I notched it for the "L" tap and finished with blue zip ties.

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11418

 

Next section I did.

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11419

 

Finished with blue zip ties.

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11420

 

This section is flexible rubber hose and is larger diameter than the metal pipes.

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11421

 

Ruh-Roh that doesn't fit.

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11422

 

Zip tied on anyways. It can't hurt right? and it's under the tmic so it won't be an eye sore unless I'm under there anyways.

 

http://legacygt.com/forums/picture.php?albumid=2484&pictureid=11423

 

First impression: I just can't tell if this helped or not. I drove my car after the install and the air blew icy cold, but it was parked in the shade with the windows down while I worked. I put a test thermometer in the vent and parked it in the sun with the windows up, so I can test it out better next time I drive it.

[08SpecB_DE]

Did the shop tell you your pressure readings?

[YeuEmMaiMai]

That's not really how refrigeration works- the cooling happens when the liquid refrigerant evaporates (latent heat of vaporization), and is rejected as it condenses (latent heat of condensation). You're not really cooling the liquid refrigerant in the same way as you cool, say, engine coolant (you do a little when it's in the condenser, I suppose), you're compressing and cooling a gas until it turns back into a liquid. How much extra liquid volume you design int the system isn't going to affect system performance, although it might affect compressor duty cycle, it's just extra. You'll get better performance at the extremes (high ambient temperatures, which is where heat pumps are least efficient) out of a larger condenser (more surface area = more heat transfer, all others being equal), but 99% of the time, you'll just have overdesigned and/or mismatched heat exchangers that hold way more refrigerant than you really need. Extra margin equals extra price and extra refrigerant that could end up vented to the atmosphere.

 

tl;dr- you'd have to make everything bigger, adding more refrigerant alone won't change anything.

 

Since I have both cars I can actually compare the two

 

1. the condenser in the '03 legacy is roughly the same size as the "14 model

2. the compressor is larger

3. the evaporator is actually larger in the '14 but the one in the '03 legacy is a folder over design so it is hard to do a surface area evaluation/comparison

 

larger compressor means you can move more refrigerant at idle larger compressor typically requires more refrigerant

 

you all keep saying efficiency this and that but the obvious answer is the system was not clearly designed to work at idle as well as it should be able to. If it is a hot day and you are sitting in traffic barely moving, you are not going to be as comfortable as you should be.

 

if I were to take an educated guess I would bet my last $ that A/C performance was sacrificed for efficiency... FYI the Forrester also suffers from this issue the '15 loaner I had A/C did not work well at idle either.

 

IMHO the best thing to do to get better performance would be to TINT the windows on the car so that you are not getting as much sun load on the system.

 

BTW the 15+ legacy uses a lot of the same parts and does not seem to suffer the same issues so I guess that they made a subtle change somewhere... (Evaporator, compressor) but the condenser appears to be a different part from what I can see...

 

I have tinted windows on my 2002 CL type S and I rarely have the fan speed above 2 even on the hottest days

[Sarang]

Did the shop tell you your pressure readings?

 

I did it myself. I have a gauge for the freon pressure but I didn't think to use it. If I don't like my results I may check the pressure but the car seems to be plenty cool when moving; it just sucks at idle.

 

I think that the varying AC performance between different cars from different manufacturers just represents their different priorities. Just about every OEM has a 3.5 V6 but they all have different ratings; I think of the ACs as being along the same lines. My parents had a '99 Crown Victoria that had AC so cold that you wouldn't point it right at you even in the Phoenix summer, but it had horrible mileage too.

Increasingly stringent efficiency ratings have got to be putting pressure on OEMs too. They wouldn't put the EGR system on the newer FA20Dit if they didn't have to.

After all, my AC is plenty cold on 90 degree days.

[Sarang]

Ok I got to test it in scorching conditions twice so far today:

The first time the test thermometer showed 145F at start and it didn't seem any different at all. I let the car idle to cool down initially for about 3 minutes and then drove normally. It seemed to cool down quicker once I was moving but that could be perception error.

The second time the thermometer showed 165F starting out and I'm fairly sure that it cooled down faster. For this one I started driving immediately which might have made a difference.

I did notice that in both cases the coldest it got was about 60F which is warmer than I would like. Ideally I'd like to see lows of 45-50. I will check the freon pressure next.

[08SpecB_DE]

It was 60 in the cabin or 60 coming out of the vents?

[FLlegacy]

I think 60 given the ambient temps is good.

The blend door closing properly may also be a good thing to check. I am going to assume you had the ac on recirculation.

 

Sent from my SAMSUNG-SGH-I337 using Tapatalk

[Sarang]

60 coming out of the vents. yes it is on recirc (it always is) and the auto climate is set to "LOW"

My gauge indicated that the freon pressure was on the low side of normal so I topped it off up to the high side of normal. No change in vent temps.

I did some googling and it seems that these cars like to give out 60F air at the coldest, possibly for efficiency reasons. supposedly the premium trim even warms up to 65ish after ten minutes.

I'm probably done messing with it. 60F at the vents on a 110F day is ok. My AC works fine, just not great. Maybe if I ever had my engine out again I'd ask what I could do to improve it such as a new compressor or a bigger condenser

[08SpecB_DE]

The auto part store freon is not the proper way to check the system. Do you have a gauge set as in high and low pressure or just the can indicating it's "full"?

[Sarang]

yeah that's why I used a pressure gauge hooked up to the low pressure side

[Aces36]

Before I did the insulation I had to run the a/c on recirculate on the 4th or 5th fan setting constantly just to be somewhat comfortable. And that was in spring when it wasn't that hot out. Today it was 95 degrees in NY and the car cooled quickly and I ran the fan on the 2nd setting. Maybe the foil tape over the insulation really helps in deflecting the heat from the hoses. I also have 50% tint on the two front windows and 35% on all the rear windows so maybe that helps a little too.

[Sarang]

So perhaps this is different since I'm in AZ, but cars come standard from the dealer with the maximum legal tint, and running on recirculate is standard too. They pretty much have to be since we get temps above 110 for weeks at a time.

I have considered getting darker tint, but having to have the old stuff removed increases the price quite a bit.

[08SpecB_DE]

yeah that's why I used a pressure gauge hooked up to the low pressure side

 

That's only half the story. You need to see what the high side is reading as well. I worked on a Maxima earlier this week where a guy did the same thing and actually overfilled the system by almost a pound. I also pulled out about 5 oz of oil which must have been in the ac pro stuff he used because more than 2 oz is almost unheard of (when pertaining to a machine pulling out oil). $125 later and he's got ice cold air and no chance of destroying his compressor or expansion valve.

 

Moral of the story, paying someone a small amount of money now to know for sure everything is okay could end up saving you a lot more in the future.

[08SpecB_DE]

So perhaps this is different since I'm in AZ, but cars come standard from the dealer with the maximum legal tint, and running on recirculate is standard too. They pretty much have to be since we get temps above 110 for weeks at a time.

I have considered getting darker tint, but having to have the old stuff removed increases the price quite a bit.

 

Hair dryer, razor blade, goo gone and some patience will get the tint off. If done slowly, you will be able to pull it all off in 1 piece.

[Sarang]

That is interesting information. I don't think my gauge goes high enough to be of any use on the high side. I would really consider turning it over to a professional if I thought that I was getting sub normal performance, but I found lots of threads on here about people with fifth gens who noticed the 60F vent temps and were not happy with it.

It seems to me that our system would be capable of colder temps, but are held back by something. Maybe a different theristor would change that? I don't really know; I couldn't find any info online.

[08SpecB_DE]

High side is a different fitting so the gauge you have will not work. I agree, if everyone else has the same complaints it's probably just the car. Someone will have to do some digging to find out where the issue lies.

[YeuEmMaiMai]

well I did some online research and the basic consensus is that a car typically loses about 1/2 ounce per year of r134a.... so evacuating and recharging to the correct level may go a long ways towards fixing low performance at idle

[08SpecB_DE]

It's a sealed system so it shouldn't lose anything unless there is a leak somewhere.

[YeuEmMaiMai]

It's a sealed system so it shouldn't lose anything unless there is a leak somewhere.

 

research it yourself...

[cww516]

http://www.watkinsheating.com/blog/the_cause_of_freon_leaks/

 

First link on google if you search for "do refrigerant systems lose refrigerant over time". The answer is "no, unless there's a leak".