An oil cap is a small component that screws onto the oil filler neck to keep dust, dirt, and other contaminants from getting into the engine oil. It also prevents engine oil from splashing out as the engine runs. Over time, the oil cap can be damaged and fall off. Sometimes you can lose your oil cap under an unexplainable circumstance.
If you are reading this, you are likely in such a situation and need a temporary fix. You are lucky if you can access duct tape or a towel and a rubber band. You can use these items to seal the oil filler opening and prevent spilling oil when the engine is running.
Using a temporary oil cap seems far-fetched because of the conditions in the engine bay, but driving without it is not a good idea either. So, what do you do? Let’s dive in for details on what you can use as a temporary fix and how to use them.
Lost Your Oil Cap? Here is What You Can Use Until You Find a Replacement
I have been in this situation myself and understand how frustrating it is to have oil splashing everywhere in the engine bay. You risk ruining your engine if you drive the car without an oil cap. The debris and dust interfere with the lubrication system. That is why we recommend the following hacks as temporary fixes before you can buy a replacement part:
Using a Rubber Band and a Towel or Rug
You can easily find a rubber band and rug when you have lost your oil cap. These two items can be an effective temporary fix if used correctly. Proceed as follows once you have them:
- Clean the oil filler neck and threads on the opening to remove any debris and dirt.
- Place a clean towel or rag over the exposed oil fill hole and ensure it’s all covered.
- Use the rubber band to tightly hold the rug or towel in place.
- Cut the excess hanging towel or rug to prevent possible oil leaks
Remember, this is a temporary fix. This only allows you to drive to your destination or an auto parts shop to buy a replacement oil cap.
Using Duct Tape
Duct tape is one of the multifunctional items you should have in your car. Fortunately, it can be bought at any retail outlet near you. This makes it a viable temporary fix to the problem. Get your duct tape ready and proceed as follows:
- Clean the oil filler neck and around the filler hole
- Wrap the duct tape around the hole until the gap is entirely sealed
- Push the duct tape down using your hand and ensure a tight fit.
- Add more duct tape around the first one to firmly hold it around the oil filler neck.
- Once again, push it down with your finger and secure every edge. This ensures the duct tape does not fall off under oil pressure when you start the car.
Reminder: buy a replacement oil cap whenever possible instead of relying on temporary fixes. It is for your safety and to avoid damaging your engine.
Indications of a Loose Oil Cap
Oil caps cannot just fall off. It usually happens when you loosely screw it back after an oil change. Fortunately, you can tell when your oil cap is loose and about to fall off by observing the following indicators:
Illuminated Check Engine Oil
A loose oil cap causes oil pressure to drop. The pressure sensors detect this, and the engine control unit illuminates the check engine light. Don’t ignore it!
A loose oil cap can cause oil to be forced into the combustion chamber as the oil pressure increases. This will cause engine knocking, which should be inspected immediately to avoid severe damage to the engine components.
Reduced Engine Oil
The low oil level light can be illuminated on the dashboard if the oil cap is unfastened. That is because a loose oil cap causes a leak. At this point, you need to check the oil cap and possibly top up the oil before proceeding with your trip.
Burnt Oil Odor
The leaking oil spills on the hot engine parts and burns. This emits a terrible oil smell inside the cabin. Pull over when it is safe and inspect the engine compartment for leaks. Also, check the oil cap.
Reduced Fuel Economy
A loose oil cap causes a loss of oil. This interferes with the engine’s efficiency as it will need more power to overcome the increased friction forces between the moving components. The overall effect is low mileage per gallon.
Engine Oil Cap Replacement Cost
Regardless of how it happens, replacing the lost oil cap is the only permanent solution. So, how much should you budget for?
The cost of replacing an engine oil cap depends on the make and model of your car. Typically, the price ranges from $10 to $50.
You won’t incur labor costs if you can screw the cap onto the oil filler yourself. It does not require any skills!
Are all engine oil caps universal fitting?
No. Engine oil caps are not universal. The design and size vary from one engine to the next. If you lost your oil cap, look for an OEM or aftermarket part specific to your car’s make and model.
What happens when you drive without an oil cap?
Driving without an oil cap offers a pass ticket to dust, dirt, and other debris into the engine, inevitably causing damage. Even the best oil filter cannot save it from this number of contaminants. Engine oil will also leak through the open oil filler neck.
How long can you drive without an oil cap?
Your car can drive for a few miles without an oil cap but don’t think about it. Just find a replacement or a temporary fix before starting the engine to protect it from imminent damage.
Is it safe to drive without an oil cap?
No. It is unsafe to drive without an oil cap unless you are ready for costly repairs to your engine. Significant amounts of oil will splash out, and debris enter your engine.
Driving without an oil cap should never be attempted. But what should you do when you have lost it and are nowhere near an auto parts shop? You can use duct tape to cover the oil filler opening. Alternatively, a rubber band and a towel can do the work, as described in this post.
Always look out for signs of a loose oil cap and fasten it on time to avoid getting into this situation. Ensure you tightly screw the cap back whenever you replace the engine oil.