How to test A/C in cold weather? Should I just remove it? - Fuel Economy, Hypermiling, EcoModding News and Forum

rwyler · 02-06-2009, 10:29 AM

I recently bought an 86 Civic Hatchback Si, and it came with air conditining that the previous owner says "works". It's been below freezing here in KY for weeks, so I haven't had a chance to test it out. If it truly does work, I want to keep it for the summer months. If it doesn't, it's going to go in the trash.

How can I test and see if it works in the winter?

I'd like to just remove it personally, but my wife wants to keep it. How much FE savings could I reasonably see from taking it off? I know the whole system probably weighs about 40 lbs, and there's another belt and pulley on the engine that doesn't need to be there. But with it turned off, how much is it really hurting me? What all is actually turning since the A/C clutch is disengaged? Along the same lines, could I just take the belt off during the winter and realize some gains? I'm not sure if this would cause damage to the compressor though since it would just sit there all winter getting full of slush and salt without spinning any of it out. Does anyone have experience with this? Thanks!

Daox · 02-06-2009, 10:49 AM

You won't see real big gains with removing it. Just hang on and wait until its warmer out to test it.

Ryland · 02-06-2009, 11:10 AM

If you want to keep the ac, you should really run it at least once a month for a minute or so to get the oil in the system moving around so the seals don't dry up, if you do this then it will last many years, this is why the ac on new cars comes on every time you start them, or comes on every time you us the defrost.
It's a pain to remove the under dash part of the ac, but the engine compartment stuff is easy and weighs around 35 pounds all together, removing the belt will show the biggest gain as v belts have alot of drag on their own.

rwyler · 02-06-2009, 11:33 AM

Quote:

Originally Posted by Ryland

If you want to keep the ac, you should really run it at least once a month for a minute or so to get the oil in the system moving around so the seals don't dry up, if you do this then it will last many years, this is why the ac on new cars comes on every time you start them, or comes on every time you us the defrost.
It's a pain to remove the under dash part of the ac, but the engine compartment stuff is easy and weighs around 35 pounds all together, removing the belt will show the biggest gain as v belts have alot of drag on their own.

So what would 35 lbs and a V-belt deletion be worth on a 2000 lb econobox in terms of FE? Along the same line, I'm thinking about removing the rear seat and some other unnecessary items. If I can shave 100-150 lbs from the weight of the car, will I see any gain in MPG? I'll be logging the FE so I guess I would find out eventually but I'd rather not waste my time doing something that won't get me any real gain.

TestDrive · 02-06-2009, 12:09 PM

Quote:

Originally Posted by rwyler

How can I test and see if it works in the winter?

I'd like to just remove it personally, but my wife wants to keep it. How much FE savings could I reasonably see from taking it off?

When the car is fully warmed up and the heater is blowing hot air, switch to AC. if it's blowing cold air within a minute or two, it's working.

IMHO. Not enough FE gain to warrant ticking off your wife.

Even on an '86 the AC probably runs when you set the controls to defrost. Defeating it for the winter probably involves nothing more than pulling the power wire to the AC compressor.

wwest40 · 02-06-2009, 01:35 PM

Many modern day A/C compressor clutch circuits are disabled when the outside temperature is below about 35F. The early ones shut down at about 45F due to head pressure.

Ryland · 02-06-2009, 06:20 PM

rear seat might weigh 40 pounds total, it's mostly foam with a wire from and a little bit of sheet metal.
the ac compresser that I removed from my 92 civic from what I tell from the wiring diagram the a/c is only controlled by the dash switch at least from looking at the wiring diagrams for the '86 civics and the '92 civics like I have they do not have an auto on function when you turn the car on.