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Car loses power when ac turned on..can someone help?

11-10-2004, 09:21 PM
Hey everybody...I have a 99 buick lesabre and for about a month now ive noticed when i turn my ac on it seems my car runs loses acceleration and has a rough idle....but when i cut my ac off..its fine....i looked under the hood and there is a metal line right above where the coolant goes and it is leaking a little bit of not sure if this is normal to leak water or not...any help would be appreciated..thank you.

11-11-2004, 11:21 PM
No kidding all cars are like that. AC always takes away power, in any car.

11-11-2004, 11:45 PM
What metal line? Transmission coolant line? The A/c coolant/refrigerant line? High pressure or low pressure?

If it's one of the A/c refrigerant lines, it should not be leaking water. There is no water in it... in fact, unless under pressure, refrigerant is gaseous. HOWEVER, the lines do carry very cold refrigerant, which means water will condensate on them. I expect that is what you are seeing. The only liquid you could see leaking from a refirgerant line would be refrigerant oil, which would be a yellowish greasy accumulation at the point of the leak.

The engine turning the A/c compressor on should not cause rough idling or engine stumbling. However, when the A/c compressor is engaged, the engine does have to work harder. Idle will increase, acceleration will decrease slightly, and you'll lose some fuel milage.

With your car parked and idling, hood up. If you kick the A/c on and watch the compressor, you can see the clutch engage as needed. When the electric clutch locks, you'll be able to hear the idle increase and the engine start working a little harder.

However, that's all you should hear. It shouldn't sound like it's about to die, misfiring, or stumbling.

11-12-2004, 08:22 PM
^^ok, thanks for the not sure what the line is called i just know its real cold to the touch when i turn the ac on....and where the nuts are connected...i guess thats condensation coming out...i know that the ac takes away from power..but lately it has gotten worse then before. i changed the fuel filter...that helped a little.My car only has 41000 miles on it so i would not need new sparkplugs would I??

11-12-2004, 09:00 PM
Nope, manufactuer specified interval for the 99 LeSabre spark plugs should be 100,000 miles. That is, unless you have some serious problems with your engine, blown head gasket etc, that would damage the spark plugs. Double-check your owners manual to be sure it's 100,000 miles.

Besides, you said the car only looses power when you turn on the A/c right? The car has a normal amount of power when the A/c is off, but as soon as you press the A/c button there is a noticable drop in power?

Again, you should be able to open your hood, look at and listen to the engine, turn the A/c on, look and listen to the engine, turn the A/c off... etc. The change in your engines behavior, noises, etc would point more towards the cause.

In addition, with the engine hot, when you turn the A/c on, the second fan on your radiator should kick on immediately. If it doesn't, then that could point to a couple fault sensors that I know are tied to other systems. (How do I know? I had one of whatever one it is go out years back on my 1995. Whenever you'd turn on the A/c, the cruise control would die... still haven't figured that one out. LOL)

The line that is really cold to the touch should be the high pressure refrigerant line. The water you are seeing is likely just condensation. You shouldn't be seeing it only there the line connect to the accumulator, there should be condensation down the whole line (as the whole line should be just as cold).

However, if the humidity is low there, I suppose you may only get noticable condensation on the accumulator. (The canister looking thing the line connects to.)

Then again, as you live in Galveston, it's not very likely the humidity is all that low. (Even with it being insanely cold in Texas this week. BTW, I hail from Dallas. That's the only reason I know what the weather in Texas is like.)

Now, if you can only see liquid where the line connects to the accumulator, that would be strange. Best thing to do in that case would be to get some of the liquid on your fingers and rub them together. If it feels oily, you're probably leaking A/c compressor oil. (Which is a bad thing, and I would recommend not running your A/c or defroster until a mechanic leak tests and refills the system.)

11-12-2004, 09:11 PM
^^ok thanks for the help...and yeah you already know about the humidity in just now got cold here last night...if it is that ac compressor oil, would it cause the engine to stumble and lose power..or u think thats something entirely differnet?

11-13-2004, 12:14 AM
Well... I don't know a hell of a lot about A/c compressors, as they aren't something that normally gets rebuilt. (A/c systems require a lot of special tools to service, as you have to comply with federal EPA regulations regarding the release of air born pollutants into the atmosphere.)

However... A/c Compressor Oil exists to lubricate the compressor. If a large amount of the oil has leaked out for some reason, then the compressor could begin binding up due to lack of lubrication. Eventually the bearings inside will seize and stop turning all together. If such is the case, when engaged, the lack of lubrication would theoretically cause the compressor to require much more engine power to turn the compressor.

So yeah, it could cause a loss of engine power, IMHO. But remember, I don't repair A/c systems for a living by any means.

06-24-2007, 09:40 PM
I am having almost the same issue but when i turn on my air it sounds like it clicks off and on and it make my car bog down the its fine then i bogs down again and it will do this until i turn the air back off. Do you think that my A/C compressor is going bad?

06-24-2007, 09:54 PM
I am having almost the same issue but when i turn on my air it sounds like it clicks off and on and it make my car bog down the its fine then i bogs down again and it will do this until i turn the air back off. Do you think that my A/C compressor is going bad?

That definitely sounds like you have lost most of your freon and the low pressure causes the system to cycle rapidly(that click sound you hear). The bogging is most likely a damaged compressor taking a lot of power to turn. I'd be willing to bet your AC system is damaged and needs repair.:frown:

06-25-2007, 09:02 AM
Sorry but please check the date and do not resurrect or reply to old threads. The guidelines are posted at the advisory stick at the top of the forum "Posting in Closed or Outdated Threads" and AF Community Rules. Start a new thread addressing your issue. Thread closed.

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