If you do fix it, try a hydrocarbon refrigerant..seriously. https://www.duracool.com/

Yes, I recently went from 40 MPG on my VX combined to 34 MPG on my last 'estimated' trip. No scan gauge. This was my first use of A/C for a long period this year.

Also, my first summer with this car. It is a '92 with a small engine, and without a crazy engineering breakthrough, aka lots of money, to completely overhaul the way the blower and a/c compressor affect the power consumption in whatever way possible...its going to be a hassle during summer months.

Well, at some point your discomfort will affect your ability to implement FE driving techniques as well in a fatigued state(i.e. hot car)

typically it is comfortable enough to just run the fan in the am, even perhaps cracking open a window. with the heat of the afternoon, and subsequent quicker warm-up, my FE is generally very near the am run, even w/ a/c on.

Yes, it was quite surprising how much my last two fill ups varied based on how I used the a/c. Of course, it took me realizing the drop in FE by 5 MPG. :eek: :D

I typically have been able to get another 40 miles than where I was when I filled up again. My VX has a 10 gallon tank(?) and I've been putting in 5 gal/stop to get an accurate idea of how much gas I'm using. Typically, for every 5 gallons I could reach 200 miles solid until the A/C had to come on. After that I got barely over 160 before needing to fill up. You can't always rule out a tank of bad gas either. Now I'm at 120 with 2 1/2 gallons left.

I don't want to run the tank bone dry every time; as contaminants tend to settle to the bottom of said tanks, but since I just got the car I need to know what it can do now compared to the work being put into the car. Long overdue, but educational. Of course, with 240k ish miles, it will need SeaFoam and Lucas in the tank from time to time anyway. I'd rather burn out whats in there as far as those additives before replacing the LAF sensor that's shot...but all of that is another story.

$150 new compressor plus shipping... ;)

Since the lines are probably open...you'll want to flush everything out really well... :D

Back in the day, when I had a car with that fancy AC thing, I had a long down hill drive. I did my best to only turn the A/C on when I was likely in DFCO mode. And on the way back up the hill, I made due with open windows. After turning it off, I would still get a good min. of cool air. I would have liked a more direct way of turning the compressor on and off. With the button on the dash, it seems like it takes a second or two to react. With a toggle switch connecting directly to the clutch pulley, one could flip it on every time you where slowing down, and off at a stop or accelerating. (just leave the fan on)

Currently my car's biggest problem is the passenger window isn't working 80% of the time. My girlfriend is not too happy about this, with the lack of AC and all. It seems like a loose wire in the switch, so that will be easy, then I should focus on those really crappy brakes, and that vibration it makes over 60mph (maybe a loose tie rod?).

don't know where you're from, but a/c is considered a necessity, not luxury, in florida. it's been near 100*F, w/ heat index WELL into the 100s lately. btw, if your brakes are really that crappy, i'd def get them fixed first!

I know my outer tie rods/boots are going to need replacing. I still need front brakes myself, though, rotors turned etc. I've got some old tires on the front from when I bought the car used, but they still have good tread and can hold up to 44 PSI. I'll grind them into the ground and save for a new set of 4 by the time I get the outer rods/boots finished. That way the alignment is done with the new tires on and all is well again.

Back to the original thread info: Last fill up with more efficient use of A/C was back over 40 MPG easily. Probably could have gone another 10 miles at least.

Lately my VW has felt really sluggish with the A/C on, more so than having 3 passengers in it. I don't recall it being like that in the previous two summers. It is over 37,000 miles and manufacturer's schedule for spark plug replacement is 40,000 miles, so maybe that's related.

Of course, with it sluggish I'm forced to shift at higher RPM and it definitely affects my FE.

That sounds like something is up. Three passengers would be equivalent to about a 6hp loss, and a compressor shouldn't be using noticeable more than that. I would pull one plug and see how cruddy they are. Some VW's like to drip oil on the plugs when the valve seals start to wear, so you may find that you'll benefit from more frequent plug replacement. Or the way a cheap skate like me would do it; pull them, rinse the tips in acetone, gap them, and put them back.

The car is too new for any of that. 2008 with 37,000 miles on it...

It's also a lease and I don't care to put that attention into it. I turn it in at 45,000 miles. I'm hoping I can get away with not doing the spark plugs; they probably do them when it's turned in either way. It's better for the experts to find whatever problems it may have and fix them under warranty than it is for me to replace the plugs and they see new plugs...

ahh yes, new car owner stuff, I hope to never have to deal with that.

wat? How can you tell me that 150lbs*3 = 6hp? Further more he says 3 passengers, and I don't know if that's including himself but if it isn't, then it's 600lbs! 600lbs or even 300lbs is a big deal in a car and should have a far larger effect than only 6hp!

I hope to deal with new car stuff again some day, but that's the last new car I'll have for a long time. I do enjoy the smooth, quiet ride and the known history of a new car, and I love that toxic new car smell.

I have never owned a new car. If I ever did buy a new one you can bet I got a hell of a deal on it.

From what i've heard (maybe not the most reliable sources) 75lbs = -1hp. I wasn't factoring it the driver, as it's hard to get a baseline without one.

As far as new cars: I would like to own one some day, but I don't think I could justify it, unless I get filthy rich some day. So much so that I could buy it outright. But that is looking unlikely.

Jay - one of the nice things about a new car is that you get to break it in just the way you want to. I bought 1 used one - my first and after the summer had to rebuild the motor since it was only driven to church on Sundays by a little old grandmas ... yeah really ... engine full of carbon and no getup and go at all. After having the engine rebuilt and then some head work on it by me it was one of the fastest 1965 Rambler Americans with a flat head 6 in the area. All my other three cars were new and lasted 12 to 14 years each with a lot less headaches than the old used Rambler. I am now on my 4th car . . . 65 Rambler (72 June), 80 VW Rabbit (80 January), 94 Geo Metro (93 December) 2006 xB (05 November). Oh yeah and 2 new and 1 used motorcycles sprinkled in there.

For me, the new vehicles I like are prohibitively expensive to buy new. I just can't see paying upwards of $40,000 for a pickup truck, when I can get a nicely equipped, used one a couple years old for under $20,000.

I have been slowly making my way towards "newer" cars though. Here are the cars I've bought over the years:

1981 Buick Regal Limited (1990, 88,000 miles) First car that was all mine, and nobody else's. I had inherited my grandmother's 84 Buick Skyhawk when she died, and I traded the Skyhawk for my sister's Regal. (still owned, currently has about 173,000 miles on it.)

1974 Chevrolet C/10 Custom Deluxe. (1994, 190,000 miles) Paid $1,000 for it. Best value in a vehicle I ever had. Ran flawlessly. Sold it to my sister in the late 90's with over 300,000 miles on it for $1,200 ($100/mo for 1 year)

1986 Chevrolet C/10 Silverado. (1996, 95,000 miles) Paid $5,000 for it. Hands down this was the prettiest truck I ever owned (when I got it) (Still owned, 190,000 miles currently)

1998 GMC Sierra K1500 (~2005, 109,000 miles) Paid $13,000 for it. Newest vehicle I've ever owned, and the only one purchased from a dealer. (still owned, 170,000 miles currently.)

Next vehicle: (hopefully purchase on Wednesday!) 2006 Harley Davidson Dyna Super Glide FXDI. Bike has 15,000 miles on it, and I hope to get it for under $8,000.

I keep my vehicles for a very long time, and I get my money's worth out of them.

About the only thing I'd like to do with a new car is start it off with a conventional oil for the "break-in" period. Really, to break it in hard and switch to my synthetic oil of choice after the first 2-3k miles.

That strategy is the best for people who buy new vehicles. It's fine for used buyers, but used buyers also have the option of selling sooner.

I really like that you can get a car for $1000 and it's value doesn't change, as long as it keeps running. Your never going to beat that with a new car (with the exception of a few collectible cars that you can't drive). Even if you junk a $1000 car every 6 months, you'll still spend less than payments and insurance on a new car.

wait... what was this thread about anyway?

Ok, I figured it out. When the A/C is on, it's really hot out. I generally don't use A/C until it's very hot. I really enjoy open windows.

So today it was really hot, I had the A/C on, and I was in city stop & go traffic. Come to think of it, I was in quite a bit of traffic the last time I used A/C and noticed it being really sluggish. Today it was awful, there was no power at all under 2000rpm. Usually I don't get above 2000rpm (until I run out of gears). I was driving around at 3000-4000rpm trying to avoid holding up traffic. Launching was tough!

IAT was 182 and coolant temperature was up to 243. I think the grille blocking combined with traffic, hot weather, and A/C are to blame. I think:
- high IAT reduced my power
- A/C leeched plenty of power
- A/C further heated the intake air and the air around the radiator
- overheating caused the computer to pull timing and reduce power

It wasn't just A/C, but rather a bunch of things that were severely exacerbated by A/C, almost in a feedback loop.

I think it's worse this year because I don't think I ran 100% grille blocking in previous summers.

Have you tried flipping the A/C on and off, off when accelerating, on when cursing or slowing. It would give you back the power the compressor is robbing, but wouldn't help with the other thing going on.

Careful you don't burn out your cooling fan with that grill block. I would guess it's running non stop, unless you disconnected it.
I use a 85% radiator block, but only in months I'm using heat. It makes me nervous to see that needle clime above where it normally sits, and listening to that fan blast away doing almost nothing.
Also that fan is using electricity it's getting from the alternator, which is getting it's power from my gas tank. I'd like to try and tweak my thermostat so that it runs a little hotter, without the ICU trying to cool things down.

LOL!

Anyway, the car automatically disables A/C at WOT, so now that you mention it the power loss was actually not including A/C.

It was still running when I parked the car and shut it off. :eek:

It was definitely NOT efficient.

Ha ha ha, only in a German car.

I don't know about current models, but small 80's model Fords did that as well.

Watch out what your laughing with. Japanese cars start the cooling fan up even under these circumstances:
- automatic AC on
- Ignition switch on, engine off (!!)
- Engine + radiators stone cold

About AC: I definitely feel it when my AC switches on and off when driving at steady speed. I can't tell the exact difference but it influences my consumption as my fuel consumption doesn't seem to change between summer and winter. So I guess that the better FE I should get in summer is lost by my AC. What contributes to this: my engine is small and its power is low. What makes that AC is responsible for a big percentage of fuel consumption in summer.
You can see this in my gasslog: very steady, from September last year till now.

Most modern cars come with a warning sticker under the hood saying that the electric fan can start and run when the car is off. I don't think it's limited to German cars.

I'm hoping my AC won't be as much of a 'drag'; no pun intended, now that my new drive belts are on. No more squealing pulley! Though, it may have been belt slippage all along. Still, the car feels much smoother now w/ AC on, especially when under engine load.

My car doesn't do that one any more; the second cooling fan (the AC one) is rolling around in my back seat :D

:thumbup: Nice work.

If the belt statrs to squeeeek....
Do Not use belt dressing.
Do not replace the belt.
Your tensioner idler arm is wore-out and that throws the pully out of alignment, making it squeak.:)

Yeah, with how tight that through bolt was on the idler pulley no wonder why it was squealing so bad.

As an experiment I decided to see what the difference was in mpg if I used the AC liberally but only on the freeway for one trip, and did not use the AC at all for another trip.

With AC: 335.5 miles at 43.63mpg
Without AC: 304.3 miles at 47.62mpg

Despite there being a 30 mile difference between the two fill ups the routes I drove to achieve these results were very similar.

That is almost a 4mpg or 9% difference and it would be an even larger discrepancy if I had used the AC for city driving.

Since other people in this thread have reported a 5-6mpg drop it seems that:

Using the AC in a Civic VX causes a 9-14% drop in fuel efficiency.

An intangable to seriously think about;
Noise, such as wind and vehicle road noise coming in open windows, damages ears and usually results in the perminant noise called Tinnitis.
Factor that into the cost of a little more fuel and the increased comfort of the A/C.

Quiz:
How many of you from Phoenix drive with the windows open?

Windows open, or closed?

Windows sometimes open while driving in the city. Always closed on the freeway. Just used the fan on the freeway.

I'm not recommending people drive with the windows down on the freeway. In fact I would gladly take a 6mpg hit when it is 100 degrees out. I just really wanted to have some concept of how much it costs to run the AC in my car.

Solution?

Wear ear plugs.. Funny thing about ear plugs is that there is a frequency range in which they're most effective, and I've found they tend to be most effective for things like computer fans and whatnot. So maybe using them on the highway would work because it wouldn't filter sirens too well but it would work well for road noise.