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How Long Can You Drive With a Bad Engine? Longer than you think!

Never a good time for an engine to let go, and being without wheels just isn’t an option for most folks. Buying a new engine or new car stings when you hadn’t planned to. It makes sense then to know how long the old girl might limp along.

I’m a mechanic with twenty-five plus years of experience, and in this post, I’ll answer that exact question and offer you some tips and tricks to help extend your engine’s life.

An engine may be described as bad because many of its components display varying degrees of wear. That said, modern engines rarely blow up; they are far more likely to continue to limp along, possibly for thousands of miles.

In this post, we’ll attempt to categorize how serious your engine’s problems actually are. That way, we’ll attempt to estimate how many miles you can realistically expect it to last.



Common engine failure symptoms

Engine failure categorized

How to extend engine life

Risks of driving with bad engine

Common Engine Failures Symptoms

When engines fail in the movies, they always blow up, you know, in spectacular Hollywood style. Of course, that’s not the way it happens in the real world. Engines do sometimes fail outright, but it is far more likely your engine will fade away slowly.

And if I do my job correctly, after reading this post, you’ll have some idea how slowly your motor is fading away.

Like any machine, an engine has a weak link. Different engines have different failure points, and how the engine was maintained and used will play a part in determining which parts fail first and, ultimately, how long your engine lives.

Let’s take a look at the common symptoms and the reasons a mechanic might have described your engine as bad:

  • Engine smokey – Rings worn
  • Overheating – Head gasket failure
  • Excessive gas use – General engine wear
  • Excessive oil use – General engine wear
  • Rattly engine – Camshaft noisy
  • Cam to crank timing out – Worn timing chain
  • Rattly top end – Lifters worn out
  • Misfiring – Valve worn out
  • Engine rattle on startup – Worn oil pump
  • Smoky on start-up – Valve stem seals worn
  • Nosy bottom, end – Bottom end bearings worn out
  • Engine rattly when revving – Worn out timing chain
Valve damage

An old engine has many components in varying degrees of wear, and a mechanic may well describe it as bad because one or more of the above-listed symptoms are present in your engine.

A mechanic does so because they are really saying this engine is uneconomic to repair and, therefore, “bad.”

A bad engine, in this sense, is still capable of giving service, possibly for thousands of miles, if treated correctly. And I’ll share those tips a little later.

First, let’s categorize your engine failure and attempt to estimate its chances of survival.

Engine Failure Categorized

In this section, we’ll marry your engine’s symptoms to the likely reason your mechanic called it bad. That way, we’ll have a chance to estimate how long your engine may last. I’ll also include some tips and links where you’ll find the products I recommend particular to your complaint.

Ok, let’s get stuck in!

SymptomLikely FaultTop TipEst Miles Left
Engine smokyRings wornAdd oil treatment5k plus
Head gasket failureAdd head gasket treatment1k plus
Excessive gas use General engine wearAdd oil treatment5k plus
Excessive oil use
General engine wearAdd oil treatment5k plus
Excessive oil leaksGeneral engine wearSeal conditioner10k plus
Rattly engineCamshaft noisyAdd oil treatment5k plus
Cam to crank timing out Worn timing chainAdd oil treatment3k plus
Rattly top endLifters worn outAdd oil treatment5k plus
MisfiringValve worn outN/A1k plus
Engine rattle on startupWorn oil pumpAdd oil treatment5k plus
Smoky on start-upValve stem seals wornSeal conditioner10k plus
Noisy bottom endBottom end bearings worn outAdd oil treatment3k plus
Engine rattly when revvingWorn out timing chainAdd oil treatment3k plus

I recommend Lucas oil conditioner, I’ve been using it for years, and I found it has a good success rate; certainly worth a try. You can check it Lucas out here on

The estimated time left is exactly that, a rough estimate. Every engine is different, as is the severity of its particular condition.

How To Extend Your Engines Life

Car oil filling

You’ll notice a ton of oil treatments on the above list, and that’s because the kindest thing we can do for the old girl is to make sure she’s well lubricated.

Oil treatments are good, but they aren’t miracle workers. However, they do offer your engine a good chance at making another thousand miles or more for just a few dollars.

A worn engine rattles because there’s excessive play between the internal components; adding the thicker oil treatment helps fill those gaps by coating them in a thick sticky layer of lube.

After adding the treatment, you’ll immediately notice the engine sounds a lot quieter. Quieter is good; it means the engine internals aren’t making as much contact. Less contact equals less heat, less wear, more power, better gas mileage, and most importantly, it will extend its life.

The next best thing we can do to increase our engine’s chances of living a little longer – drive like it’s the only car we’ll ever own.

Us mechanics see a ton of vehicles, and it’s amazing what you can tell about a car just by observing its general condition. The correlation between how loved a vehicle appears and how it’s driven and maintained is freakishly accurate.

How we treat our machines will have the greatest impact on how long they will last. Here’s an experienced mechanics list of top maintenance tips that are guaranteed to help your vehicle live longer.

  • Check oil levels with every gas fill
  • Change oil (Premium grade) long before its scheduled due date
  • Garage your vehicle, especially in winter
  • Power wash the underside after winter
  • Wash external and vacuum interior once per month
  • Wax paintwork four times per year
  • Change brake fluid every three years
  • Change and backflush your coolant system every four years
  • Use petroleum jelly on battery terminals
  • Change your cabin filter every year
  • Use silicone grease on the brake caliper slides
  • Copper grease your hub-to-wheel interface
  • Change your wiper blades every year before winter
  • Use Rain-X on your windshield
  • Use silicone spray on window runners
  • Use white lithium grease on the hood, trunk and door hinges and latches every year
  • Rotate your wheels
  • If the spare wheel is stored externally, lube the fasteners before winter

Risks Of Driving with Bad Engine

We should, of course, talk about the dangers of driving a mechanically compromised vehicle. A bad engine may expire instantly under certain circumstances. Towing a trailer, high-speed driving, or generally laboring the motor will, without a doubt, increase the chances of instant failure.

And instant engine failure is dangerous, especially at highway speeds. Instant failure likely means the internal moving components fuse together and seize solid. The sudden loss of power will leave you stranded and perhaps in the outer lane of the highway.

And if that’s not dangerous enough, consider the manual transmission driver. In a stick-shift vehicle, the driving wheels will lock up, causing the vehicle to skid uncontrollably.

While adding the above-mentioned oil treatments to your engine may mask the underlying problems, it won’t fix them. Driving a vehicle with a bad engine comes with some risks.

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