Can You Drive With a Blown Spark Plug?


Spark plugs can blow out and cause a lot of problems such as lack of acceleration, bad gas mileage, rough idle, and weird noises. But many people ask ”can you drive with a blown spark plug?” Is it safe to get your vehicle to the repair shop or should you call a tow truck once you have a blown spark plug? I talked to several mechanics in my town and here is what I found out.

Can You Drive With a Blown Spark Plug?

Can You Drive With a Blown Spark Plug?

Can you drive with a blown spark plug? You shouldn’t drive with a blown spark plug and since you probably can’t get it out because the heat has welded the spark plug, you need to remove the coil and the inductor wires from the blown spark plug so that way that particular spark plug is disabled and won’t do damage to the engine.

Each cylinder has a spark plug that ignites the air and fuel mixture into the combustion chamber. A car with 8 cylinders (V8 engine) will have 8 spark plugs, one for each cylinder. What happens when a spark plug is blown, no sparks would be created to ignite the air and fuel mixture in that particular cylinder.

Basically, your engine now has to overwork the remaining 7 cylinders in order to compensate for the lost cylinder. When a spark plug is blown and your engine loses a cylinder, you will experience a lack of power, poor engine performance, bad gas mileage, rough idle, different engine noises, and smell of gasoline from the exhaust.

Now, the question is, can you drive a car with a blown spark plug? If you carefully read my article so far, you will know that you shouldn’t drive a car with a bad spark plug. The safest thing that you can do is disconnect the spark plug wires and thus disconnect that electrical current to that spark plug and drive your vehicle to the mechanic shop.

When a spark plug is blown, it can be hard for you to remove it at home. This is because when a spark plug blows, extra heat is generated and the spark plug can get welded. There is a great chance that you will destroy the spark plug wiring while trying to take out the blown spark plug.

But, if you want to change your spark plugs at home, here is how to do it.

Is your engine oil due for a change? Visit our Car Fluid Guide Website to learn the importance of changing your oil on time, which type of engine oil is best for your vehicle, and much more.

How To Fix Oily Spark Plugs

If you are changing the spark plugs on your engine, only to discover that your spark plugs are covered with oil, don’t freak out, it doesn’t mean that your engine is going to blow up. It just means that your spark plug tubes are leaking. You can fix that problem by yourself.

  1. Take out the spark plug wires and put them aside.
  2. Remove the clamps off the hoses that go to the valve cover and pull them off.
  3. Put aside or remove any wiring harness that is in the way of removing the valve cover.
  4. Remove the valve cover. The spark plug tubes are built into the valve cover. So, you have to remove the valve cover to change them.
  5. If the valve cover is stuck, get a screwdriver and pry under.
  6. Locate the leaking seals and take out the old spark tube gaskets.
  7. Put a sealer on the new spark tube gaskets and place them on top of the spark plug tubes.
  8. Put the bolts back on and tighten them up.
  9. Reinstall the hoses and the spark plug wires back in.
  10. If you spilled any oil on the engine, clean it with a brake cleaner so the car won’t smoke when you turn it on.

What Causes Spark Plugs To Get Wet?

Spark plugs can get wet from the oil, gas, or coolant. Changing out wet spark plugs will only temporarily fix the problem. But, you have to know what caused the wet spark plugs and how to fix the problem.

Each spark plug can tell a story of what’s going on inside your engine. This ”story” of what’s going on in the engine is written on the electrode and the porcelain of the spark plugs. There are three things that can cause a spark plug to get wet. Here is what causes spark plugs to get wet.

1. Rich fuel mixture

Can You Drive With a Blown Spark Plug?

Too rich of a fuel mixture on the electron on the spark plug will show up as a gray to matte black finish that will be evenly distributed over the spark plug electrode and the porcelain. This happens when there is too much fuel being sprayed in the cylinder.

A lot of that carbon residue glues up on the hot parts of the spark plug. If you see a spark plug like this, there are a couple of things you need to look into:

  • Look at the long term and short term fuel numbers to see what the engine is doing.
  • Inspect the state of the injectors. A clogged injector or an injector stuck in an open position might be causing this condition.

2. Engine oil leak

Can You Drive With a Blown Spark Plug?

A spark plug that was wet from engine oil will have a burnt black finish. But, in some cases, it’s going to be a shiny black finish and it’s not going to look the same as carbon deposits from fuel. It can be inconsistent and even build up on the other side of the spark plug where it’s colder.

Your spark plugs might be getting wet from oil because crankcase vapors and oil droplets are getting into the combustion chamber. This can be because of the positive crankcase ventilation system, outrings, or other things. So, make sure you diagnose this problem before you put the new spark plugs in.

3. Coolant

Can You Drive With a Blown Spark Plug?

Your spark plug could be getting wet because the coolant is finding its way into the combustion chamber. This usually happens when the head gasket is leaking or the intake manifold gasket is leaking.

A spark plug that has been wet from a coolant leak will have a gray ashy appearance. The appearance may change a little bit depending on the type of coolant that’s in the vehicle. Before you replace all of the affected spark plugs, you will have to check your cooling system for any potential leaks.

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