26
votes
Accepted
Would it be harder to install a new AC system if the old one is ripped out already for a long time?
Keep the AC system in the car until you are ready to get it repaired. There's a load of parts to an AC system and some of them are hard to access, you are likely to spend much more in labor costs ...
- 17.1k
21
votes
What is most fuel efficient at 130km/h?
It depends on several factors:
The car's aerodynamics
The AC compressor load
Temperature differential between the desired temp and the outside temperature
The SAE did an experiment, the full results ...
- 17.1k
16
votes
Accepted
Is it okay or useful to run heat and AC at the same time?
You're meant to.
In fact, in older cars, it was automatic when redirecting air to the window defroster. On this GM control, the far right position would activate the A/C compressor.
Almost always, ...
16
votes
Vehicle AC works initially, but after driving for a while (hour+), the airflow drops to the point being ineffective
The evaporator is the component of the AC system that gets cold. It is located after the blower in the passenger cabin. As it cools the air that is passing over it, moisture condensed on the cold ...
- 25.5k
14
votes
A/C not cold when idling
The AC often relies on the the electric fan near the radiator at the front of the engine bay running to cool the refrigerant. If the fan isn’t running while stationary there won’t be sufficient air ...
- 25.5k
13
votes
Are A/C Control Panels Universal?
In a word No, not even close. Some are all mechanical, some vacuum, some completely electronic. some are combined with the infotainment device (radio) even the ones of the same type from the same ...
13
votes
Accepted
For safety, must one have the vehicle's engine turned off before attaching A/C manifold gauge sets to top off the A/C system?
It's not necessary, your engine won't explode and your AC system won't burst if you connect the couplers while the engine is running, in fact it will make no difference whatsoever. If the AC system is ...
- 17.1k
12
votes
Accepted
How do A/C professionals dispose of refrigerant?
When I got my Refrigerant Handling Certification from MACS many years ago, we were sworn to use a proper recycling machine, which captured everything and filtered out air, oils, and moisture. The ...
- 12.4k
12
votes
What is most fuel efficient at 130km/h?
Keeping a constant speed using cruise control with windows shut and ac on because once the cabin is down to temperature it requires little to keep it there and the ac will modulate its power needs.
...
- 34.7k
11
votes
For safety, must one have the vehicle's engine turned off before attaching A/C manifold gauge sets to top off the A/C system?
I, MTA, some random guy on the internet, give you my permission to do repairs in any manner that you feel is consistent with your own personal safety.
Joe Lawyer, who wrote the instructions, has only ...
- 7,463
10
votes
Is it okay or useful to run heat and AC at the same time?
Yes, it is useful, okay and won't cause any damage.
The usefulness comes from the fact that the AC not only removes heat from the air, it also removes moisture from the air (because cold air can't ...
- 15k
10
votes
Accepted
How to recharge my A/C
First, a word of warning. To do it right (and not waste expensive refrigerant, or risk ruining your A/C compressor), you'll have to get a few pieces of equipment. If you're just going to do this ...
- 1,364
10
votes
Will running engine after replacing A/C components ruin the new compressor before system is recharged with freon/oil?
Your compressor should be clutch driven. If so, then running the engine won't do it any harm. The clutch won't engage the compressor without a refrigerant charge present. With the pressure at ...
- 160k
9
votes
Accepted
What's ECON and how is it used properly?
It probably has a Climate Control unit which regulates the temperature automatically. This means that the air conditioner should always try to reach the requested temperature.
So when it's outside 30 ...
- 288
9
votes
Can running the heater with the A/C on damage your car?
No way. In fact the system is actually designed that way.
The Air Conditioning (A/C) system on your car runs automatically when you are in the Defrost mode. Like you say that setup removes water ...
- 6,569
8
votes
Accepted
When idling, AC does not work and engine overheats. What's the cause?
A few things spring to mind:
confirm radiator fan operation (per user3188168's suggestion)
The fans are vital in ensuring air flow across the both radiator and A/C condenser when the car is ...
- 39.2k
8
votes
Vehicle AC works initially, but after driving for a while (hour+), the airflow drops to the point being ineffective
Another answer but less likely the solution is that the inside temperature sensor is faulty or being obstructed causing the system to think it's already cool and turns the fan down and temperature up. ...
- 3,420
7
votes
Accepted
Will cold air blow if A/C Clutch doesn't engage?
No. It wont cool without the clutch engaged. That is how it pumps and therefore cools the refrigerant. (someone correct me if I'm wrong) -- If you can see the belt on your engine, you should be able ...
- 856
7
votes
Accepted
How is a variable displacement A/C compressor controlled
Since this variable displacement compressor features only a clutch coil cable and no solenoid valve cables, it's "internally controlled", that is, it doesn't require any control at all from an ...
- 958
7
votes
What is most fuel efficient at 130km/h?
Fuel efficiency shouldn't be your only consideration. Rolled down windows will expose you to noise levels well above 85 decibels which can cause permanent hearing damage with prolonged exposure.
...
- 1,187
7
votes
Idling motor and running AC for 4-8 hours in 100 degree heat?
It shouldn't cause the vehicle any issues. Realistically, all you'll be doing is burning fuel. The wear will absolutely be minimal, mainly because at an idle, there is very little stress put onto the ...
- 160k
7
votes
A/C not cold when idling
You are right to ask questions about this. The very first thing a mechanic should do is a pressure check of the AC system, if the pressure is low then it makes sense to look for leaks. If the pressure ...
- 17.1k
7
votes
For safety, must one have the vehicle's engine turned off before attaching A/C manifold gauge sets to top off the A/C system?
Do yourself a favor by following guidelines/friendly advice/legal liability issues. As someone not 100% familiar with vehicle refrigeration, be extra cautious; when ac runs, normal operating pressures ...
- 1,298
6
votes
Accepted
Does a constant blown fuse always indicate a short?
If the fuse is blowing as soon as you perform an action it's a short to ground.
Multimeter won't do much good in this situation. It'll come down to wiring diagrams and visual inspection of the ...
- 10.7k
6
votes
Accepted
BMW 3 series 320D ac blowing hot air
Did you see the compressor kick in? If not, I'm thinking your car doesn't have any refrigerant in it. If they put the gauges on the system and it didn't register anything, that's a pretty good sign it ...
- 160k
6
votes
Are A/C Control Panels Universal?
No. Sorry. Absolutely not. If you stay within the same marque/brand you might have half a shot.
For instance, a Chevy Cruze HVAC module has a better chance of working in your Pontiac, as GM, Ford, ...
- 12.4k
6
votes
A/C still malfunctions after repair. How concerned should I be?
My experience with AC is limited to what I have been studying both in book and video form. From everything I'm reading you really do need to replace the receiver drier when you replace the compressor. ...
- 9,296
6
votes
Accepted
Why does the radiator fan have to start when turning the A/C on?
In a nutshell: The radiator fan comes on so the A/C works at its highest efficiency.
The A/C condenser (the part which sits in front of the coolant radiator) is a heat exchanger. If air isn't ...
- 160k
6
votes
Would it be harder to install a new AC system if the old one is ripped out already for a long time?
Don't rip it out. In addition to what GdD said, some parts of the system, particularly the evaporator core, likely make up part of the seal between the engine compartment and the heating/AC ductwork. ...
5
votes
What is the purpose of AC re-circulator?
Another reason to turn on the re-circulation is if you don't want any intake from the outside for some reason.
- 786
Only top scored, non community-wiki answers of a minimum length are eligible