An internal combustion engine is a big air pump that sucks air when its pistons move down. When this happens, it creates a vacuum that is then used for assisting the brakes, operating the A/C system and exhaust gas recirculation system. However, when it comes to modern vehicles equipped with direct injection, a turbocharger, a start-stop system or variable valve timing, the amount of vacuum produced by an engine on its own is not enough for operating all supplementary systems. For this reason, the majority of modern vehicles come equipped with a mechanical engine-driven or electrical vacuum pump.
Diesel and electrical vehicles do not generate any vacuum on their own. That’s why a properly functioning vacuum pump is vital for their operation, so it can be found under the hood of any of these vehicles. Their vacuum pumps are primarily responsible for efficient braking, so most of them are considered a safety feature. If the vacuum pump of a diesel, electrical or hybrid vehicle fails to operate, the driver will have to deal with a lack of a braking assist, improper operating A/C system and, in some cases, a poor steering assist.
If you’re not confident whether your vehicle has a vacuum pump or not, you can check your owner’s manual or get in touch with your nearest dealer or mechanic. But, as a general rule, if your vehicle features direct fuel injection or a start-stop system, or variable valve timing, or a turbocharger, most likely, it has a vacuum pump. Besides, an electrical vacuum pump is must-have equipment for every diesel, hybrid and electrical vehicle.
How can I know that my vacuum pump is failing?
A failing vacuum pump will alert you of a problem in one of the following ways or combining all of them:
Poor braking performance
Under normal conditions, your vacuum pump provides a proper power assist when you push down the brake pedal. If it fails or malfunctions, you will have to step on the pedal much harder to stop the vehicle. This is very dangerous and can put your life at risk, which is why you should not drive a vehicle with a “hard” brake pedal. What you should do is to call your mechanic once this problem is detected.
Improper operating air conditioning, heating or ventilation systems
Your vehicle’s climate control system relies on your vacuum pump to operate properly. If the pump fails, you can feel like driving a 50-year old car with no A/C conditioner on a hot summer day.
Oil leaks underneath the vehicle
A mechanical vacuum pump is lubricated and cooled by engine oil. If it breaks or its housing loses the sealant, the oil that is circulated under high pressure can leak down. You should not ignore oil leaks found under the vehicle. If their source is your vacuum pump, it must be replaced or repaired as soon as possible. Get in touch with your mechanic and ask him or her for advice.
Can I drive a vehicle with a bad vacuum pump?
The short answer is no. A properly operated vacuum pump is crucial for your braking performance. If you don’t want to put your life and the lives of your passengers at risk, you should not drive a vehicle with a malfunctioning vacuum pump. A bad vacuum pump may also affect your climate control system.
How can I fix a bad vacuum pump?
Once you notice any signs of a bad vacuum pump, the first thing in your must-do list should be a thorough inspection of the pump. This is very important since there can be another source of the problem. It is better to leave this job to a professional, unless you’re a mechanic yourself.
If the root of the problem is your broken drive belt, a leaking vacuum hose, or poor electrical wiring, it can be replaced with a new part. However, if the vacuum pump features severe damage, the entire vacuum pump assembly should be replaced.
Replacing a vacuum pump is not a part of routing vehicle maintenance, which is why it should be done by a professional.