is AC bad for the engine?

[hadansi]

engines always seems to be happier when the air conditioning isn't turned on. does A/C strain the engine or cause any additional wear?

[sarujin]

Air Con works by drawing power from your engine. So when your aircon is on, your engine loses some power to the aircon. With you aircon off your engine gets slightly more power and runs better.

On some small cars 1.3litres having the aircon on makes it hard to get up some hills, the engine has that little power.

sarujin

[SaabJohan]

On the specs I have seen the AC pump consumes between 0,7 and 11 hp. The pump can be turned on and off by a magnetic clutch. Some engine management system turns off the pump during high loads.

[Steel]

Originally posted by sarujin
Air Con works by drawing power from your engine. So when your aircon is on, your engine loses some power to the aircon. With you aircon off your engine gets slightly more power and runs better.

On some small cars 1.3litres having the aircon on makes it hard to get up some hills, the engine has that little power.

sarujin

Hey now, my 1.3L engine has NO problem getting up those hills AND running A/C of course i ripped out my A/C as well as my P/S, but that's besides the point.

[delamothe]

In addition to the compresor taking more horses out of the motor, you also have the heat generated by the condenser which is usually in front of the radiator (on most cars - other cars have it right next to the radiator.)
This is why two items are critical to prevent overheating; a thermostat that is in good order, and a radiator / condenser that is free of any junk lodged in the cooling fins, preventing airflow.

[replicant_008]

For the reasons sarujin explained the use of the ac drive does consume power (which is why you perceive the car to be running sweeter when it's off), the additional power to drive the ac also means that when doing the same speed you will consume more gas so reducing your mileage.

As for causing additional wear or damaging the engine - if you are working the car at heavy load or in unusually harsh conditions (eg loading the car up, start/stop commuter driving in harsh hot conditions, driving up mountainous country @ altitude, driving in desert conditions) the additional load that the ac drive will have will increase the load on your engine. Which is why running ac under heavy loads can lead to overheating which is bad for your engine.

Also a maladjusted idle speed can also lead to your engine stalling @ idle when the ac is on (this doesn't happen that often these days).

Removing accessory drives such as ac will improve performance and mileage - however ac does make the cabin more comfortable and prevent tiredness as does power steering so it's a six of one, half a dozen of the other question.

Personally I won't a car without ac but if you lived where I did you'd understand.

[Chris]

It is less costly power wise to have the window down than the aircon on.

Steel: You ripped out the AC and PS? I admire your passion. Of course, if I could afford an 88 MR2 SC or 323GTX, the aircon, sound, pw, pl, back seat (323), most carpet, etc, would be history.

[Steel]

Chris: well, yeah but both my AC and PS is broken. Although i like driving without PS now, because i can REALLY feel the road, and now i know exactly when my wheels are gonna lose grip and stuff, all because i dont have PS. But even if they worked, i'd take em out anyway because im going to start Autocrossing this summer:smoker2: