Causes Of Oil Leak From Drain Plug (Symptoms, Preventions, & Fixes)

Changing motor oil regularly is essential for optimal engine performance and longevity. Fortunately, it is a simplified task that a regular car owner can accomplish in under 30 minutes with the right tools and know-how.

However, some issues may arise if you make any slight mistake. A good example is an oil leak from the drain plug after an oil change. Since oil removal is done through the drain plug, you must ensure to remove and install it back securely. 

Oil leaks can create catastrophic issues for the engine, especially if it runs out of oil. Here at Rx mechanic, we don’t want you to waste unnecessary money on repairs or cause damage to your car after repairs.

Therefore, we’ll outline the causes, symptoms, preventive measures, and how to fix oil leaks from drain plugs. So, grab a seat and a cup of coffee while you read every word in this article.

oil leak from drain plug

What Causes oil leak from the drain plug

Several factors can cause car oil leaks from the drain plug. First, let’s look at the various reasons this will occur after an oil change.

Improperly tightened drain plug.

The common reason for this problem is not correctly tightening the drain plugs. This is common with amateur mechanics and DIYers. If you do not tighten the plug properly, it’ll cause oil leaks.

If the drain plug is too loose, it may fall off on the highway, and all the engine oil will leak out. If this happens, it will cause catastrophic engine damage. Don’t freak; this scenario is rare unless you guide the plug by hand and forget to screw it with a socket.

Overtightening drain plug

We’ve stressed that you should tighten the drain plug properly. That doesn’t mean you should overtighten it. Reminder, over-tightening drain plugs can damage the threads, causing oil leaks.

Worn-out or dried seals

Depending on your car model, the drain plug may use a washer, a seal, or both to ensure the engine oil stays intact inside the crankcase. These seals, washers, or gaskets can dry up or wear out over time and cause small oil leaks from drain plugs. This is common with high-mileage vehicles.

These are the common causes of oil drain plugs leaking on motorcycles and vehicles. Let’s look at the preventive measures to stop this oil leak.

How do you prevent oil leaks from drain plugs?

You don’t want oil leaks from the drain plugs because this may lead to a catastrophic engine breakdown if the engine runs out of oil. In any case, prevention is better than cure. Therefore, it is better to prevent the oil leaks from the drain plug than to fix it.

All you have to do is to ensure you guide the drain plug and screw it properly by hand before using the sizeable spanner. This will prevent you from wearing off the thread on the crankcase. Also, use a sizeable socket to prevent stripping the drain plug.

Lastly, tighten the plug properly, but do not overtighten it. Let’s see how to tell if the oil drain plug is leaking in the subsequent section.

What are the Symptoms of an oil leak from a drain plug?

Oil drain plug leak symptoms are quite obvious, like headache symptoms. The common sign of an oil leak from the drain plug is oil puddles underneath the vehicle when packed. And a shortage of oil levels.

Oil puddles

Like any sign of an oil leak, a common sign of drain plug leaks is oil puddles underneath the vehicle. The puddles may be small or large, depending on how obvious the leak is.

Greasy oil drain plug

You may not see an oil puddle under the car if you have a small oil leak from the drain plug. Instead, you’ll notice a greasy substance on the drain plug. The greasy substance is a mixture of oil and dirt.

Loose oil drain plug

Oil puddles underneath the vehicle can emit from other places. And greasy substance on the drain plug can also result from oil leaks from other places. But a loose oil drain plug is a confirmation that something is wrong.

It could mean you have a loose drain plug or a worn crankcase thread. Whatever the leading cause is, you have to fix it ASAP. I know you’ll wonder, how do I stop my drain plug from leaking?

why does oil leak from my drain plug

How to fix oil leak from the drain plug

A damaged, leaky, and loose oil drain plug will not only mess up your garage, but you’ll also cause low oil levels. The leak should be fixed once you notice it. The last thing you want is the plug to fail off and dump out all the motor oil in the engine.

Here’s a simplified guide on how to fix oil leaks from the drain plug.

Step 1: Park the vehicle

Park the vehicle in your garage or under a leveled driveway. Slide under the vehicle and see if the drain plug is properly tightened.

Step 2: Try and Turn the drain plug

Try and turn the drain plug by hand and see if it turns. If it doesn’t turn, get a sizeable socket and turn the plug. If it moves freely, you have a loose plug that needs to be tightened.

Step 3: Tighten or remove the drain plug

Tighten the drain plug if it is loose. But if it’s tight and still leaking, you either have a dried-up seal, gasket, washer, or a worn thread. Grab a sizeable socket and remove the drain plug if the latter is the case.

Kindly note that the engine oil will start rushing out once you remove the drain plug. So, get a catch pan and place it directly under the drain plug. This will prevent you from messing up the area. And you can also reuse the oil.

Step 4: Examine the seals and thread

Examine the drain plug thread and seal to see if they are in good condition. If they’re worn, get a replacement and install it to fix the problem. If that’s not the issue, check the seals and replace them if needed. You can also get an oil pan drain plug repair kit for an easy fix.

FAQs

Q: How much does it cost to fix an oil leak from the drain plug?

Fixing an oil leak from the drain plug can cause around $35 to $45 if a leaking gasket is a culprit. Technically, it is difficult to say the exact repair cost since several parameters can be the leading cause.

If the culprit is a worn crankcase thread, you’ll need a new crankcase or rethread the hole. This will cause you around $75 to $100. And if the root cause is a loose plug, you won’t spend any money. You only have to retighten the plug.

Q: What can I use to seal the oil drain plug?

Oil drain plug sealant is recommended for sealing oil drain plugs and oil filter leaks. This prevents engine oil leaks and ensures it stays where it is designed to stay (in the crankcase).

Q: Can you over tighten oil drain plug?

Do not over-tighten the drain plug or the oil filter. Doing so will strip the thread. You can also damage the plug’s seal, washer, or gasket, causing oil leaks. Another reason you should not overtighten the drain plug is that it’ll make it harder for the next service technician to remove it. The process can even make him strip the thread if he’s not careful enough.

Q: Is it OK to use Teflon tape on the oil drain plug?

A Teflon tape is very effective and can prevent leaks on several components. But is it okay to use it on a drain plug? Using Teflon tape on your drain plug or anywhere in the transmission, power steering, or engine is not advisable. This is because some pieces of the Teflon tape will eventually enter where it’s not supposed to enter and cause damage over time.

You can disagree with me on this. It’s fine. I have colleagues who still use it and haven’t complained about it. But prevention is better than cure.

Q: Can I use silicone on the oil drain plug?

I understand that silicone is oil-resistant but don’t use it on the drain plug. If you use it, it will hold the drain plug, but it’ll eventually fail. And when that happens, the drain plug will fall out. Imagine if this happens when you’re driving on the highway. It’s a “goodbye to the engine.”

Q: Does an oil drain plug need a washer?

Most drain plugs have seals or washers. If you forget to install them or they are damaged, and you fail to replace them, it’ll cause oil leaks. So, if you don’t mind having some oil leak from the drain plugs, ensure the washers are in good condition.

Q: Are oil drain plug gaskets universal?

Oil drain plugs and gaskets come in different qualities. However, there are some universal drain plugs in the market that will fit in any vehicle. In any case, when shopping for a drain plug gasket, tell the auto store seller the vehicle you want to use it on.

Q: How often should an oil drain plug be replaced?

There’s no replacement interval for a drain plug. The drain plug can last the life of the engine without stripping out or wearing off. However, some drain plug can damage over time and needs replacement.

Ideally, you should only replace the drain plug when it starts stripping off or leaking. However, if it’s leaking due to a lousy gasket or seal, replace the seal, and you’re good to go.

Final Words

Several factors can cause oil leaks from the drain plug. Whenever you notice any of the outlined symptoms above, track the leading cause and proffer a solution. The process can be extremely easy and sometimes hard for a regular car owner.

Follow the instructions above to fix the problem and prevent it from occurring again. However, if the leading culprit is beyond what you can handle, have an experienced mechanic track and fix the problem.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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