Want Colder AC? Here's How To Do It!

[BlueHorse]

Does anybody know if some of the materials discussed in this thread could be fire hazard being so close to the engine compartment?

[Warhammer]

So far it hasn't posed an issue. While running, you'll notice the larger AC lines should be what is known in the AC industry as "beer can cold". The insulation will protect the AC lines from loosing its coldness in the hot engine compartment. Hence the reason why you feel it respond faster in slower traffic. On the highway, I'm sure you won't notice too much of a difference because of the amount of air flowing.

[BlueHorse]

Do you have the name or the part number of the heat wrap you bought? I saw so many different types, and just want to get exactly what you used. Thanks.

[Warhammer]

The only thing I can say it's double adhesive high density pipe insulator. I'd have to call them and ask exactly what the part number is. I'd just go to your local professional hvac store and ask for something similar. They should have it.

[danf]

I truly hate beeing the prty pooper, the idea is great no doubt about that but I have to say that what you are doing to the lines is lethal in the long run. The material that was used looks rather spongy and absorbant. Also in general if moisture gets underneath this material it will rust and corrode the lines especially in areas like here in canada with the tonnes of salt they put on the roads

[Warhammer]

Originally Posted by BlueHorse

Do you have the name or the part number of the heat wrap you bought? I saw so many different types, and just want to get exactly what you used. Thanks.

Man...call me a slacker. I completely forgot about this one.

The place I got my material from is:

United Refrigeration
3337 Princeton Drive Northeast
Albuquerque, NM 87107-2013
(505) 883-9500

Just measure the OD of the line and get something similar to what I got. It's thick and will work.

[pridbor]

Looks like a good thing to do. The wife asked the right question: has it been corrected on the new models? if so one should be able to get the parts at the dealer for us with the early models.
And the insulation foam in your picture looks very much like what I have from my local hardware store to protect water pipes from freezing, is that what you have? But the tape you have used looks very slick, special type?

Very good and inexpensive idea to fix what should have been done by the factory!

I should have some of the sticky tape from a previous project which I will use (hoping to have enough left)

Thanks

[Eric L.]

Thinking back to the original post in this thread about wrapping the low pressure lines, I am uncertain and doubtful how that can aid in the efficiency of the AC system. However, there might be an explanation for why it seems to cool down faster initially, but I also think it will impact the long term cooling ability, so allow me to think out loud here.

The low pressure lines are the refrigerant lines running out of the evaporator core through the engine compartment to the compressor. Insulating them won't make the evaporator lines colder when the compressor is in operation since by the time the refrigerant has reached the low pressure line in the engine compartment, it has already done its cooling job (way back in the evaporator core where the interior fan blows across). The job of the compressor is to take the cold low pressure refrigerant and compress it to a high pressure (and hotter gas). Wrapping the low pressure lines will no doubt keep the contents of those lines from absorbing heat from the engine compartment, but at the same time, you are asking the compressor to do more work - take something from a lower pressure to a higher pressure. If the refrigerant warmed somewhat (thereby increasing its pressure ever so slightly) traveling through the low pressure lines to the compressor (such as from engine bay heat) it would therefore present the compressor with less total work. So I posit that wrapping the lines makes the compressor actually work harder. Also, the Murano's compressor uses the incoming low pressure line to determine the appropriate output load (its a variable compressor) - on hotter days, the warm air passing over the evaporator coils will increase the temperature (and therefore pressure) in the low pressure lines, causing the swash plate within the compressor to swing open to increase total compressor output. If you wrap the low pressure lines, you lose that little bit of warming in the engine compartment, and the compressor may not kick on full capacity to deliver maximum performance.

So what benefit can wrapping the lines do? Well if you turn off the car, the line will heat soak, and since its a metal line connected to the metal coils within the evaporator core, wrapping the lines will indirectly keep the evaporator core cooler for a longer period. So if you park the car for ten minutes, its possible the AC might be ever so slightly instantly colder when you turn the car back on again. But this does nothing to increase the efficiency of the AC system since within seconds the evaporator will be ice cold again once the AC is turned on.

A tradeoff of keeping the evaporator cooler vs working the compressor (at low capacity) a little harder? Not worth it in my opinion.

[biggijohn]

Nice job. But damn, don't you ever wipe down your engine compartment...DerTeee!! LOL

[mozo1]

Nice job. I had my MO for 4 y's and half and was wondering if insulating the low pressure line would make any difference since I live in Saudi Arabia where temp exceeds 115 F in the summer. I insulated it 8 months ago and didn't notice any big difference.

In the end it worth the try. And I want to thank Warhammer and all other members who share their experience and knowledge with us, thank you all.

[Halwg]

Originally Posted by danf

I truly hate beeing the prty pooper, the idea is great no doubt about that but I have to say that what you are doing to the lines is lethal in the long run. The material that was used looks rather spongy and absorbant. Also in general if moisture gets underneath this material it will rust and corrode the lines especially in areas like here in canada with the tonnes of salt they put on the roads

Ladies and gents, I am a corrosion engineer by profession, and this is absolutely true. We see this type of corrosion all the time on above ground pipes that have been insulated around plants and compressor stations. Moisture accumulates and condenses under the wrap and sets up the ideal corrosion cell. Failure in some cases is quite rapid.

Given the heating/cooling effect in the engine compartment, I wouldn't take my chances wrapping stuff like this without giving the lines a good coating of something like high heat epoxy, and even then I'd be very skeptical.

[miloca1983]

Originally Posted by Halwg

Ladies and gents, I am a corrosion engineer by profession, and this is absolutely true. We see this type of corrosion all the time on above ground pipes that have been insulated around plants and compressor stations. Moisture accumulates and condenses under the wrap and sets up the ideal corrosion cell. Failure in some cases is quite rapid.

Given the heating/cooling effect in the engine compartment, I wouldn't take my chances wrapping stuff like this without giving the lines a good coating of something like high heat epoxy, and even then I'd be very skeptical.

so then what would you recommend instead of doing this?


Sent from my Autoguide iPad app

[njjoe]

Refrigerant tubing on home AC units are routinely encased in closed-cell foam insulation and never have I heard of those lines failing due to corrosion.

-njjoe

[Halwg]

They corrode, as well, but they aren't under the adverse heating/cooling that occurs under the hood of a vehicle. So the corrosion rate is much slower.