How To Remove A Stuck Oil Drain Plug

When it comes to removing a stubborn oil drain plug, it can feel hopeless. How will you ever change the oil if you can’t get it off?

Luckily, this is a fairly simple job. The stuck oil drain plug should still be holding oil in the sump, so drive to a local mechanic and ask them to do it.

If you’re intent on doing it yourself, that’s also possible. But if you’re unsure, be extremely cautious!

This guide will explain why you can’t get your oil drain plug off and what mechanics will attempt to loosen it.

What Is An Oil Drain Plug?

Motor oil gets pumped around the car via the oil pump. It lubricates the engine, ensuring everything works effectively and smoothly.

It’s stored in the oil sump – a relatively large metal container bolted onto the bottom of the engine. The sump’s a bit unique in some vehicles, such as racecars and motorbikes.

An oil drain plug sits in the bottom of the sump. It’s there to allow mechanics to drain the oil out. Gravity does the rest of the work.

Once the oil flow stops, the mechanic reinstalls/tightens the oil drain plug with a fresh washer. The ramp is then lowered, and oil is poured back into the engine from the summit.

Different Types Of Oil Drain Plugs

Some manufacturers place oil drain plugs on the lower surface of the sump. Others install them pointing outwards at the base of one of the sides (usually the front or back).

Various vehicles have diverse kinds as well.

Protruding oil drain plugs are typically common hex bolts. These can be removed using regular ratchets, sockets, and wrenches.

Some vehicles’ oil drain plugs require a Torx, square, or hexagonal bit for removal.

Finally, in most cars, the oil drain plug comes out entirely. However, some vehicles’ plugs only loosen to a particular extent. The oil is then allowed to drain without the need to remove it fully.

If you are unable to loosen the plug, ensure that it is not one of these! Examine your owner’s manual or watch a YouTube video for assistance.

Why Does An Oil Drain Plug Get Stuck?

Luckily, it’s uncommon for an oil drain plug to get stuck.

The oil drain plug shouldn’t get stuck if a car has regular maintenance. Well, under most circumstances, at least.

The most likely reason for a stuck oil drain plug is rounded-off edges. This will most likely have happened when it was last replaced.

Also, rust can find its way in from the outside, meaning the oil drain plug won’t come out.

Another (incredibly frustrating!) way oil drain plugs get stuck is when previous technicians/DIYers overtighten them. It should be tightened to the torque recommended in the owner’s manual. Any more is excessive.

Even worse, you sometimes see that someone’s applied Loctite Threadlocker. Why?!

Finally, sludge accumulation within the sump could cause a bolt to seize up. Old motor oil eventually turns into sludge, increasing oil pressure. This cakes everything in the engine and stops it from working. If the sludge gets into the oil drain plug’s thread, it might solidify and prevent it from turning.

Things To Avoid Doing

The most crucial tip is to ensure you have the right tools for the job. Avoid using the following:

• Impact wrench (or other power tools)
• Breaker bar
• Adjustable spanner/wrench

Contrary to what the ever-reliable army of armchair mechanics tells you, using excessive force rarely goes well.

If someone tells you to use a power tool, disregard them. You’ll put so much force through the bolt’s shaft that the head will break off.

This is known as shearing – more about it subsequently.

Likewise, breaker bars (also known as power bars) will probably apply too much torque. As a last-ditch option, you could try using it very carefully and gently!

You’ll have to be cautious to avoid stripping or shearing the bolt.

How To Remove A Stuck Oil Drain Plug – Rounded Off

Get yourself some bolt extractors, if you can get hold of some. You should find sets online for about $35.

If you can’t get bolt extractors, you’ll need to resort to old-fashioned, unsightly methods. You’ll need some old sockets and a mallet.

The only way to do this is to hammer this bolt extractor/old socket onto the oil drain plug. You’ll need an ancient Torx/square/Hex bit for bolts with non-protruding heads.

Once your extractor/socket/bit is hammered into place, use a standard ratchet to untighten it.

You might need to give it a bit of a gentle whack with the hammer or your hand to help it along but do so cautiously. If you apply too much “shock” force, it might slip off the rounded-off head.

Watch out for the oil spilling out onto you.

Throw the old oil drain plug away. It’s worthless. Buy a new one and fit it with the new washer. Tighten it up to the recommended torque. You’ll find this in your owner’s manual.

How To Remove An Oil Drain Plug Stuck At The Thread

If the oil drain plug’s stuck due to excessive tightening, Loctite, or dried sludge, proceed with care.

It’s not necessarily a wise idea to keep applying more torque with lengthier tools. You might shear the bolt.

Spray the area underneath the drain plug with anti-seize spray. Naturally, it’ll be too snug for much to get in there, but it might give you a slight extra boost.

You might also consider cleaning the area with brake cleaner. Removing as much grease as feasible again won’t make much difference. However, every small bit helps.

If you can loosen the bolt, even a fraction, it’s a positive sign. Squirt more anti-seize spray in there, wait a few minutes, and try again.

In theory, bit by bit, you’ll be able to remove the oil drain plug without stripping the thread.

Eventually, it should come out. Don’t get too excited and forget about all the oil about to pour on your head!

What To Do If You Can’t Get The Oil Drain Plug Out

Here are a couple of suggestions that might help.

Watch How Much Easier It Is On A Mechanic’s Ramp

It’s much easier to get enhanced leverage when the car’s on a two- or four-post ramp, like those you see in an automotive garage.

That’s partly why, when it comes to oil changes, you may as well just leave it to the professionals. They get oil much cheaper than you do, anyway.

Make Sure The Oil Is Warm Enough To Flow

Ensure the engine’s heated. As oil’s temperature increases, its viscosity decreases.

That is, it becomes “thinner.” This means it flows easier and might seep past the thread, making things less complicated for you.

Remove Rounded-Off Bolts By Switching Between Imperial (SAE) And Metric

When hammering old sockets onto rounded-off bolt heads, a useful tip is to switch from Imperial to Metric and vice versa. These sizes differ so marginally that using similar diameter sockets can do all the work for you.

For example, if a 7/16″ bolt head has rounded off, try using 11 mm. 14 mm sockets operate well for 9/16″, and so on.

Offset Spanners Are Easier Than Standard Ones

Try an offset spanner if you’re stuck using a conventional spanner and the bolt is on the bottom of the sump.

It offers you more space.

Jolting A Stuck Oil Drain Plug Free

Instead of using a larger tool, continue using your ratchet or spanner.

Use your feeble hand to hold the head/ring in place. With the base of your strong hand’s palm, hit the tool perpendicularly.

The sudden, abrupt force often breaks the bolt free from whatever’s holding it in place. You’re much less likely to shear the drain plug by this technique than by getting a longer tool.

Please bear in mind that if your hands aren’t accustomed to it, it might hurt and bruise. You could try using a hammer instead.

Don’t Forget About The Oil Flowing Out!

As alluded to, don’t forget that the oil will flow out once you remove the bolt. Don’t get it all over you or the ground! Have the oil pan in position, waiting, and ready.

What To Do If You Strip The Thread

If you strip the bolt’s thread, you’ll need to discard the outdated one and re-tap the screw hole (insert).

If you aren’t trained to do this, get some help now. It isn’t too tricky, but it’s easy to do it wrong.

The best way to learn the correct measurements is to order a replacement oil drain plug. Before proceeding, ensure it looks the same as the one you removed.

Use a thread pitch gauge and measuring tool to get the new plug’s dimensions. The diameter should match the hole precisely if it’s the correct part.

Re-tap the aperture using the correct tap and the T-handle.

The fresh oil drain plug should fit right in if you’ve done it correctly. If not, try again. Things might not work out for whatever reason, in which case you’ll need a clean sump.

What To Do If You Shear The Bolt

If you apply too much torque for the oil drain plug to handle, it’ll snap off. It’s not necessarily your fault – it might be so trapped it’s beyond expectation or perhaps deteriorated throughout.

Your only realistic option is now to extract the oil with an extractor. You’ll then need to remove the sump from the bottom of the engine and clean out any remaining oil.

Now, drill the sheared bolt out. Be careful because oil is combustible – make sure you clean it well. Re-tap it (as above) and install a new plug and washer.

Reattach the completed sump to the car and pour the oil in, sticking to the recommended grade and quantity. Run the engine and check for leaks, observing until the engine warms up.

If drilling and re-tapping don’t sound like a feasible option, you’ll need an entirely fresh sump.

Conclusion – Removing A Stuck Oil Drain Plug

If your oil drain plug won’t come out, all is not lost! In most situations, you’ll be able to remove it without resorting to final alternatives.

Even so, you have meager reason to be concerned.

The main lesson here is that if you’re unfamiliar with cars, leave it to the experts. They do this kind of thing every particular day.

In the meantime, you can help prevent a tight oil drain plug by replacing it every three or four oil changes.