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Can You Drive with a Bad AC Compressor

Can You Drive with a Bad AC Compressor

It was the middle of summer, and the heat was pressing in. Temperatures were reaching highs of 109 degrees Fahrenheit.

I waited until sunset to get into my car to get something to eat. Although the heat was subdued by the setting of the sun, it was still oppressive.

I cranked up the AC – nothing. I mean something was blowing out of the vents. But it wasn’t the cool blast of air conditioning I was so richly anticipating.

The AC wasn’t working. The compressor had gone bad.

I was still able to make my thirty-minute drive to get something to eat. And I was able to make another thirty-minute drive the next morning to get my car checked out by a mechanic.

My point?

You can easily drive with a bad AC compressor. For a while, anyway.

In what follows we’ll look at some of the symptoms of a bad compressor as we answer some of your burning questions about driving with a bad AC compressor.

Symptoms of a Bad AC Compressor

When the heat is sweltering and the only thing blowing out of the vents is warm stuffy air, it’s not a pleasant feeling.

Here are some of the most obvious symptoms of a bad AC compressor:

Inconsistent AC Performance

When the air from your car’s AC vents isn’t as cold as you remember, that’s a huge warning sign that something might be wrong with the compressor.

Noise from the Engine

If you engage the AC switch and hear whining, chattering, squealing, chirping or rattling. This could be a tell-tale sign of an AC compressor that’s on the blink.

Noticeable AC Compressor Damage

Moisture is the enemy of an AC system. When you look under the hood, do you see obvious signs of damage to the compressor like corrosion or any part of the compressor that’s bent or broken? You’ll likely need a new compressor.

Compressor Clutch Won’t Engage

An AC compressor has a clutch that connects to a vehicle’s engine. When you turn on the AC, it should engage and start spinning. If it’s not spinning or you hear screeching or a whining sound when it’s engaged, you’ll know the compressor needs servicing.

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Fluid Leaks

An air-conditioning compressor also has internal bearings which keep refrigerant from leaking out. Because of the constant pressurizing needed to keep the refrigerant cool, the bearings become worn out which causes the refrigerant to leak.

How an AC Compressor Works

How an AC Compressor Works

An AC compressor is a long tube that goes back and forth through cooling fins.

You’ll find it mounted in front of the engine’s radiator where it can better take advantage of the forced air provided by the engine fan and motion of the vehicle.

Warning: Here comes an oversimplification…

An AC compressor is the main mechanical component in an AC system.

Driven by the serpentine belt, an AC compressor’s primary job is to move refrigerant in a pipe by pumping it from the evaporator -> to a condenser -> to an expansion valve -> and back to the evaporator.

A Bad AC Compressor Can Trigger a Check Engine Light

A Bad AC Compressor Can Trigger a Check Engine Light

A bad air conditioning compressor won’t always cause the check engine light to come on – it didn’t in my car.

But there are different types of AC compressors in vehicles. A bad high-voltage electric compressor can trigger a check engine light.

Remember that the AC compressor is connected to other parts of the engine.

So, other types of compressors can trigger a check engine light due to its interrelatedness with the rest of the engine.

Because of this, it can be challenging to pinpoint what exactly is triggering the check engine light.

A Bad AC Compressor Can Also Affect Vehicle Performance

Although you can drive with a broken AC compressor, it’s not ideal.

Remember that this mechanism is connected to the rest of your engine via pulleys and belts.

The problem is if the pulley should break, or the belts should slacken because of a bad AC compressor. The engine then has to work harder to compensate.

The longer you drive with a bad AC compressor the more damage you can cause to the engine.

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Not to mention the entire air conditioning system.

How a Bad AC Compressor Effects the Engine

So, exactly how can a bad AC compressor affect the engine?

A major issue is that it can cause the engine to stall. Like many ancillary parts of your vehicle, the AC gets its power from the engine.

A bad AC compressor can throw off the idle rotational speed (or idle air control).

It’s a valve that determines the amount of air that bypasses the throttle plate in a fuel injected vehicle to adjust idle speed.

And if it isn’t controlled, the engine won’t be able to cope with loads produced by various systems within your vehicle.

Can the Heater in Your Car Be Affected by a Bad AC Compressor?

A bad AC compressor won’t necessarily affect the heater in your car. The reason is because the air conditioning system and heater are completely separate units.

However, the heater does use elements of the air conditioning system.

For example, if the AC isn’t working properly, you might find that the heater isn’t able to defog your windows efficiently when you turn on the defroster setting on a cold morning.

Diagnosing a Bad AC Compressor

Diagnosing a Bad AC Compressor

So far, we know that a stuck AC compressor is what causes the air conditioning in a car to stop working.

But how do you diagnose an AC compressor failure that can negatively affect the engine?

Here are six ways to go about it:

Check for Temperature Fluctuations

An AC compressor can work even if there is another issue with the air conditioner. To begin isolating the problem, find out if the temperature from the vents stays consistent when you’re driving at different speeds.

Turn the AC to the Highest Setting

While the engine is running, turn the AC on to the coolest setting and turn the fans up to the highest setting. Listen for any skipping or loud noises coming from the belts connected to the compressor.

Inspect the Compressor

What you’re looking for is anything that looks like the AC compressor has been damaged in any way. Friction increases when there’s not enough oil in the compressor, which can also lead to inconsistent temperatures.

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Check Belts

Is there enough tension on the belts connected to the compressor? Are the belts damaged in any way? Cracks and splits in the belt material can cause damage to the AC compressor.

Inspect the Clutch

The clutch is located at the front of the compressor. You want to ensure that it has enough room to move with the system freely. You should feel minimum resistance when moving the clutch’s hub.

Look for Leaks

Like an engine’s cooling system, the air conditioning cooling is also a closed system. Low refrigerant is a sign that there’s a leak. There are air conditioning refrigerant leak test kits which come with a special dye that shows up under UV light to detect refrigerant leaks.

AC Compressors Are Built to Last a Long Time

Generally, an AC compressor should last for a vehicle’s lifetime – typically 12 to 15+ years.

But like with everything else associated with automobiles, its longevity depends on your ability to keep up with maintenance.

An annual AC life check will help ensure your air conditioning lasts as long as you own your ride.

Cost of Replacing an AC Compressor

If you’re like me, you buy most of your cars used.

No matter how well you look into an automobile’s background before purchase. It’s tough to tell exactly how diligent the previous owner was about looking after a vehicle before handing the keys off to you.

And even if you get a brand-new car, things still go wrong. Getting the AC serviced in my car cost around $915.

Replacing a bad AC compressor can cost between $800 and $1500.