I have a thermometer probe stuck inside the center air vent of my new Fit and I cannot get it to show less than 42F even when it was in the lower 80s here in NJ few days ago. Today we had a heat blast here and the temp was a bit higher at around 43F while I was driving with outside temp in the upper 90s. So this tells me one thing. The outside temp does not make a whole lot difference with how cold the A/C can really get.

Anyone have any ideas on how to get the temp lower? I was thinking in wrapping the shiny pipe under the hood on the left side of engine that gets condensation with some kind of insulation tape/foam to try to not have the temp lost as the R134a is circulating in the system and that pipe warms up and starts condensing during operation. Good idea? Oh and I would not want to go to the dealer and have them check the system as this could cause a never ending leak and I would have to take the car in to get recharged with R134a on a regular basis. My old 2003 Mazda Protege 5 never had any kind of A/C service performed and the A/C works great after all these years!

 

Anyone have any ideas?

 

I've read and heard from some on this forum that if your AC isn't cool enough you should take your ride into a dealership (preferably one that's on the level... one you can trust!) and have them check the coolant level.

Some here who have reported less than stellar AC performance have apparently found their coolant levels were way low from the factory. They had the coolant level raised to maximum and reported proper system cooling afterward... as in functioning satisfactory.

I had a problem with the AC being cold enough in hot weather with my 2010 Fit Sport, but can't speak for the new 2015+ Fits.

Report back your conclusion, if possible. Would be curious to know if your AC problems are resolved, and how it was resolved.

Thanks

 

I have 2015 EX


What I've noticed so far is that the air doesn't get very cold when first starting the car, but once you get up to highway speeds it will freeze you out to the point you will have to turn it down.


You might also try turning off your ECO mode - supposedly the A/C doesn't get as cold with it on but I haven't noticed much of a difference.


I live in OKC, so right now it's 98-100 w/ crazy humidity and I have no complaints on the coldness. The highest setting is too loud so I usually keep in on 3 or below but find myself turning it down to 1 on my commute home (approx. 45 minute drive one way)


It does seem to take a few minutes for it to get cold but this is typical of most vehicles I've driven. Hope this helps!

 

I've found that if you drive around 3-4k RPM for a minute it gets colder faster when you first start up.

 

So does anyone think that wrapping the metal A/C pipe on the left side of the engine is a good idea? It does get cold when A/C is on so I think it's warming up by being exposed to the high heat under the hood.

 

I've done this on my ST and am tempted to do the same on the FIT. This time I would be inclined to do a before and after measurement with a thermometer to determine how much (if any) it helped. I just used the smallest pipe foam for <$1 per 6 ft from Lowes/Home Depot (plumbing dept).

 

So this pipe foam does not melt in the high temps that exist under the hood? I want to do it but wondered if it can resist very high temps. The other day it was like 100F outside and I'm sure under the hood was a lot hotter. Another thing I'm wondering about is why this is not done at the factory? maybe this pipe is not supposed to be insulated?

 

It also needs to meet some non-flammable requirements. Seems like a bad idea.

If the engineers thought it needed to be insulated, don't you think they would have?

 

No this is Honda...

 

Nope, has not melted in the ST one year+. I wonder why they allow cold refrigerant to run uninsulated from the compressor to the firewall when your a/c outside your house is heavily insulated from the compressor into the house?

If there is some technical engineering reason that it is not insulated, I would love to hear it.

 

Ok so yesterday I went to Home Depot I got my self sealing tube of pipe foam insulation. Will attempt this mod this week and see if I get my A/C to go below 40F. I just need to find time when the engine is cool so I don't accidentally touch something got and have a boo boo. As soon as I know I will post the results.

 

For the results to be meaningful you need to control for air temperature and humidity or your before and after numbers will be influenced. If your before case is 90/90 and your after case is 75/60, a temp drop measured in AC output may have nothing to do with your mod. All the Honda shop manuals I've looked in have a graph to get normal temp out from temp in and various curves for humidity.

 

BTW, it just occurs to me: if this pipe you guys are worried about gets COLD, it's an evaporator return not an evaporator supply line.

<pedanticanswer>The supply line is compressed and warm/hot. When the refrigerant it carries is evaporated it gets cold. That's where the cold in the AC comes from. Warming the return line from engine bay ambient is irrelevant--and may even be a slightly good thing from the point of view of the efficiency of the refrigeration cycle. The refrigerant is about to get compressed like crazy and get really hot. The hotter the better. This is where you are adding energy--and why AC costs engine power as it converts that power to heat in the refrigerant (and mechanical losses in the compressor). Then it will go though the condenser to dissipate as much of that heat as it can in the air slipstream coming through the grille. Then it will go to the evaporator, get evaporated, and cold again. The colder the better right up until the point that the evaporator core is so cold as to freeze up all the condensate its forming from the water in the air moving through it. This effect is probably what sets the limit on how cold you want to get the evaporator core. I believe they insulate the return in home AC to keep from collecting condensate on the pipe and having water drip where ever the pipe travels.</pedanticanswer>

At least that's my top of head air conditioning reverse engineering thinking. I'm open to alternate interpretations of the refrigeration cycle.

 

The cold stuff isn't running from the compressor to the firewall; it's running from the evaporator to the compressor.

There are two tubes involved, one larger for cold gas return from house to compressor and one smaller for warm/hot liquid from compressor to house. They insulate the return (they call it suction since it's sucking the cold refrigerant from the evaporator) to keep it from collecting condensate and causing water damage wherever the condensate would drip. Sometimes they insulate the supply. For aesthetics or maybe protection? I dunno.



Because they don't care about condensate dripping in the engine bay and there's no reason to worry about the line getting hot. It's carrying the refrigerant to the compressor to get heated.

As noted above, if Honda's smart engineers thought this line needed to be insulated, they would have done it. They aren't going to save $0.20 on something that would reduce AC performance.

 

@Dick.. All good info. When I tested the temperature of the same line in my Fiesta, it was pretty hot when using the A/C and the engine had been on for some time.

After wrapping it, the temperature of that line was quite cold. It seemed like a successful way to preserve 'cold' in the system, but I never measured before and after at the vent.

Is preserving this 'cold' not matter in the a/c system for overall performance?

You are probably correct that it would have been wrapped at small $ change if the engineering suggested it would improve performance.

 

Can't imagine why. The next step in the system is to use engine power to heat the refrigerant up. If you get some free heating from the engine bay all the better. But it's hard to imagine that if this pipe is warm it will warm the rapidly flowing gas it carries much anyway. Also why your insulation allowed the tube to get cold. It was better at getting warm from its surroundings than cold from the gas rushing through it.

 

I'm having a hard time understanding why the refrigerant needs to get heated? I thought it heats up by having warm outside air pass through it as it cools off the air going to the vents? Why would you need to heat the refrigerant in an A/C system? That's like saying I need to cool off the air in a heater before I heat it up again so the output air is hot. It just does not make sense to me. Anyway I wrapped my tube yesterday and did not notice a whole lot of difference but my vent temperature did reach about 40F compared to what I noticed prior of about 42F. Yesterday was less humid and a little less hot than a few days ago when I measured it.

 

This is how refrigeration works. You transfer heat from the evaporator to the condenser. I.e., from the cabin air to the air flowing through the radiator/condensor. I.e., you are taking heat form the cabin and transferring it to all outdoors. You do it using the refrigerant to carry the energy. And you compress the refrigerant along the way to heat it so that it is enough warmer than the outside air you are trying to heat or you wouldn't transfer any heat. Basic physics that make this work are gas laws and phase transition.

This is getting off-topic. And I may not be explaining it well. Suggest you read up on vapor-compression refrigeration.

BTW, all this is captured in the graphic I linked above. The car is no different in its cycle or components. picture == 10^3 words.

 

Bingo, BTW.