does everyone elses crew do this?

[Justin]

Open the hood, look at the Air conditioning pump with its two hoses going to the condensor. Then turn the climate control off, the punp shouldn't be working (won't turn)..Turn on ac...it will turn....turn switch to floor or vents, it won't turn....Now, I switch the control to defrost at windshield and floor, it turns on and off. Is this supposed to happen? Even with the temperature setting to heat, it still runs.

[Conman]

Open the hood, look at the Air conditioning pump with its two hoses going to the condensor. Then turn the climate control off, the punp shouldn't be working (won't turn)..Turn on ac...it will turn....turn switch to floor or vents, it won't turn....Now, I switch the control to defrost at windshield and floor, it turns on and off. Is this supposed to happen? Even with the temperature setting to heat, it still runs.

IIRC, if you put it to defrost the AC is in use to dehumidify the windshield.



Con

[Justin]

that blows..so you lose hp when the defroster is on.. I never knew that

[Conman]

that blows..so you lose hp when the defroster is on.. I never knew that

Some cars disable the AC if you mash the gas pedel to the floor. Don't know if ours does that. The only good thing about the AC pump being on year round is that it's not sitting all winter and could freeze up.



con

[christian]

Good thing when you think of the winters we get up here...lol

[a2b]

that blows..so you lose hp when the defroster is on.. I never knew that

ya i know that sucks.



one time i was in el paso and i had to be in louisiana in that day and then be back in california in 2 days. well my heater core went out and radiator fluid leaked into the cab. it was winter and freezing cold. it was also raining and it was 3am. i couldnt stop cuz i was in the middle of nowhere. so i kept going. the rain made the cold and rain made the winsheild fog up. but i couldnt turn the defrost on becuase the heater core busted. if i did that, i would have been stuck on the side of the road with an over heated engine. so i had roll down the window to see and to escape the radiator fluid fumes that were makeing me nausious. i drove 12 straight hours like that. didnt see the sun once. i drove lookin out the side of my truck the whole dam way!

[WFRager]

Having it run with the defrost also lets the refrigerant lubricate the compressor and seals throughout the year.

[quickbiker]

That's why I have always for years pull the plug on the compressor in the winter months. No use wasting gas all winter!

[quickbiker]

Having it run with the defrost also lets the refrigerant lubricate the compressor and seals throughout the year.

What I've heard is the new systems don't need to do that like the old system. I've heard the new systems don't use o-ring seals and use more of a tapered sealin meathod. That's what my AC friend said anyhow.

[ZoSo]

In my 95 S-10 the ac went out at about 75,000,

$1200 repair it, contaminated the whole system.

ac repair guy said the best thing is to run the compressor offen.

otherwise it locks up and when it breaks free the particles

screw-up the system. so keep it running to keep it lubed.

[Mat73GNZ]

I have a problem similar to what's described in the first post. My AC compressor turns itself on and off about every 5 seconds. The thing is, every 5 seconds the truck losses power then regains it while driving. VERY annoying. It's been doing this for about a year or so, but only when I have the fan on (any setting). It never did this before, but it's like driving at a constant speed and someone turns on and off the air conditioning. RPM's drop, then rise, drop, then rise, making the truck slow down and speed up, slow down, and speed up! Dealer had no clue when I first brought it in. I figured I would ask to see if anyone else had a problem like this.

!M!

[Ken]

Having it run with the defrost also lets the refrigerant lubricate the compressor and seals throughout the year.

What I've heard is the new systems don't need to do that like the old system. I've heard the new systems don't use o-ring seals and use more of a tapered sealin meathod. That's what my AC friend said anyhow.

R134a systems still use O-rings at the fittings and there are still seals in the compressor.
The defrost running in the winter is not that big of a load / drag on the engine. With a C.C.O.T (Cycling Clutch Orifice Tube) system the compressor cycles off once the evaporator reaches at preset PSI. So in the cold winter air there is not much if any heat load on the evaporator letting it maintains the pressure inside for a longer period. Which means the compressor does not have to kick on as often or run as long.

Now on a system with a Variable Displacement Compressor yes the compressor is engaged all the time but as the load changes so does the "stroke" of the pistons inside the compressor. With a lower displacement (cold ambient temps) you have less effort to turn the compressor and less drag on the eng.


Personally I wouldn't try to disable it from running, first of all because I live in Phoenix and use A/C year round. Secondly, because it does serve a function in the cold damp winter months in the rest of the country.

[kf6kmx]

that blows..so you lose hp when the defroster is on.. I never knew that

Some cars disable the AC if you mash the gas pedal to the floor. Don't know if ours does that. The only good thing about the AC pump being on year round is that it's not sitting all winter and could freeze up.



con

My '03 disables the compressor when you get on it.. if its a humid day and I'm on regular a/c (not max) and hit the gas, there is a short interval where you can really feel the humidity rise while the compressor is off..
Most of the GM trucks I've had, all the way up to a 454 1-ton, had this 'feature' to recover the power.