How Long Can I Drive With an Exhaust Leak? (Answered)

We’ve all heard cars coming down the road with broken exhausts before, but what do you do when it’s your own? Before we go into the details:

Driving with an exhaust leak is not recommended, as it can be dangerous for you and your vehicle. An exhaust leak can cause various issues, including reduced fuel efficiency, engine damage, and potential carbon monoxide poisoning.

How Long Can You Drive With an Exhaust Leak?

Unfortunately, there is no set time frame on how far you can drive with an exhaust leak. Firstly, it is not recommended to continually drive without seeking a repair; not only is a leaking exhaust potentially dangerous, but it is also illegal.

But regarding the exhaust, it’s difficult to determine how long it will last because there are so many contributing factors, age, rust, and hole size. But depending on the condition of the exhaust, in theory, it might be possible to drive for quite some time. Then again, with a snapped exhaust pipe, it might not even be possible to drive to a garage for repair with the muffler dragging along the floor.

However, there are times when you could drive for long periods, i.e., with a minor exhaust leak. It’s common for drivers not even to know they have a leaking exhaust. It’s not unusual to put a car on the ramp needing a different repair and spot the exhaust blowing from a leaking gasket. These are just pin hole-sized leaks and they aren’t causing any immediate problems. Even more so if the leaks come from the rear muffler gasket, there’s very little danger of exhaust gasses entering the cabin, so there is no immediate danger and you could keep driving.

Signs the Exhaust Is Leaking

  • Increased noise – The most obvious problem with an exhaust leak is the increased noise. The muffler can’t silence the noise because the gasses are leaking before they get to it. So increased noise from the exhaust is the first problem 99% of drivers will notice.
  • Reduced fuel efficiency – The exhaust has O2 sensors attached which are responsible for indicating to the car the levels of air/fuel mixture that should be injected into the engine. When an increase of oxygen is detected in the exhaust by the O2 sensors because of a hole, the car thinks it is running lean and injects more fuel, meaning it is unnecessarily burning through large amounts of gas quickly, or dumping it in the exhaust where it will backfire. Not the most obvious of signs but alongside other issues you will notice a reduction in fuel efficiency.
  • Poor engine performance – Cars with a leaking exhaust tend to suffer from a low-end of the rev range power loss. Depending on where the leak is in the exhaust, the performance overall also suffers.
  • Fumes in the cabin Smelling exhaust fumes in the cabin is the most dangerous of signs you have an exhaust leak, it may be the only sign there is an issue, but this needs rectifying immediately. Exhaust gasses are toxic!
leaking exhaust gasket

Risks of Driving With an Exhaust Leak

There are risks driving with an exhaust leak which can cause more damage to the car and harm your health. If you notice the problems below, you should not continue driving and seek repair.

  • If you smell fumes – If you are driving with an exhaust leak and you start to smell fumes in the cabin, carbon monoxide is a poisonous gas that shouldn’t be inhaled. It will put you and the car occupants at risk. By the way inhalation of carbon monoxide hospitalises 50,000 people each year. Remember, the exhaust’s job is to filter toxic gases and point them out the rear of the car so the car’s occupants don’t inhale them.
  • Extremely loud exhaust – The loud noise you can hear can get quite embarrassing when you pull up to traffic lights. Because the exhaust is leaking gasses it means the back pressure built through the exhaust system is incorrect, and the car will loose its performance. The vehicle could stutter just as you need the performance the most, putting you in a dangerous situation.
  • Check engine light on – An exhaust leak can cause the check engine light to illuminate because the emission is out. The o2 sensors before and after the catalytic converter will think the car is running lean because of the increase in oxygen detected in the exhaust. So the car will start to pump more fuel in for combustion, meaning the engine is over fuelling. This means damage is being done to the catalytic converter and other engine parts, which, as you can imagine, is expensive to put right.

Will an Exhaust Leak Get Worse Over Time?

An exhaust leak will always get worse; they always start small. An exhaust leak usually starts because the exhaust is deteriorating, so a small pinhole turns into a couple of inch sized hole in short time. Equally, gasket pinhole leaks will get larger as the gasket and the supporting flange deteriorate further with age.

Frequently Asked Questions

What Happens If You Ignore An Exhaust Leak?

If you ignore an exhaust leak you can expect damage to occur to other parts. The engine and catalytic converter are the most at risk of failing.

Can an Exhaust Leak Cause Engine Failure?

Due to the changes in back pressure through the exhaust with a leak, it can cause internal engine failure. This will not happen overnight and only happens if you continuously drive with a leaking exhaust.

How Do I Check For An Exhaust Leak?

You will need to get underneath the vehicle with the use of a ramp to properly assess an exhaust leak. Once underneath with the engine running, you will be able to visibly see gasses leaking from the problematic component. Always check around the connecting flanges first as these are generally the first parts to fail.

Bottom Line

With a severe exhaust leak and continued driving, you are doing more damage to the engine and other parts of the exhaust, so you shouldn’t drive unless it’s an emergency or to a garage for repair.

Driving with a minor exhaust leak is slightly different because it can be hardly noticeable and not cause problems. The time to worry about a small exhaust leak is if you start to smell the exhaust while driving; carbon monoxide poisoning is a real and dangerous thing!

My name is Tom although my friends call me Tommy. Messing around with cars and bikes has always been a hobby of mine even from a young age. So I made it my day job 17 years ago. I am a fully qualified mechanic as you would expect. I've worked in all different areas of the motor trade, valeting, panel beating, engine repairs, I'm sure you get the idea. I enjoy sharing my wealth of knowledge and experience with others, which is the reason I spend a lot of time here writing for this website.

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