Lost Your Oil Cap? – Here’s What You Need to Do

Are you dealing with a lost oil cap and wondering what to do about it in the meantime?

We’re here to help!

Your vehicle’s oil cap plays an essential role in keeping your vehicle reliable and running. Pressure is affected when it’s gone, so you’ll definitely want to take measures to remedy the situation.

This quick guide will give you the info you need to solve this common issue.

How to adequately cover or seal until you acquire a replacement 

In a situation where you only have one vehicle you are able to drive and simply do not have an oil cap for it, you will need to cover that hole from debris and spillage as well as seal it to the best of your abilities before driving to the auto parts store.

In order to do this, you will need a towel, scissors or a knife, and some masking tape. 

  1. Take your towel and tightly twist it into a cone/tube shape that will fit the exposed gap where your oil cap should be. 
  2. Cut the excess towel as a fire could start due to oil contaminating the towel and catching fire under the hood.
  3. Wrap your makeshift oil cap in masking tape. This allows for the towel/masking tape combination to effectively but temporarily filter the air coming into the engine as well as blocking your engine’s oil from escaping and utterly soaking your engine. 

After you have successfully crafted your impromptu filter/cap, you are ready to drive your car to the nearest location that sales oil caps for your vehicle. However, try to keep your rpm’s down and deter yourself from having a lead foot until you have successfully replaced your vehicle’s oil cap.

What happens when you drive without an oil cap?

Driving without your oil cap allows for your vehicle’s engine to become contaminated with dust and debris that will inevitably disrupt and destroy your engine, even with your oil filter, costing thousands of dollars in repair.

Another issue you may have while driving without your oil cap is the nearly constant loss of oil from your car’s engine. Chances are when you are driving without your oil cap, oil is escaping through where you cap should be and is spraying all over your engine. This is a serious issue for two reasons.

First, is that the engine will eventually run out of oil, essentially weld itself together, and die. This, of course, is the worst-case scenario, but it should not be ruled out.

The second reason is the fact that you will have engine oil completely soaking everything under your hood. This raises another issue while driving as once the oil begins to spray onto the hot engine, it will begin to smoke and eventually disrupt your field of view while driving that may cause an easily avoidable accident. 

What to do if your oil cap falls somewhere in your engine bay and you can not find it. (Is it a big deal or unlikely to be a problem?)

Regardless of where the oil cap lands, whether it is in the engine bay or pieces of the cap has fallen into the engine itself, you should find a way to retrieve it. Losing an oil cap in the engine bay may not cause immediate problems or problems at all regarding the performance of your engine, however, you will want to find it and get it removed either by yourself or professionally depending on your experience and level of comfort.

With the oil cap in the engine bay, it could be trapped somewhere that may cause it to rattle and become extremely annoying or worse, cause a horrendously strong odor due to its melting, which can find its way into your cabin to you and your passengers. 

However, if the pieces of your oil cap fall into the engine itself, you may have a much more serious problem at hand. For instance, depending on the size of the pieces that has found its way into your engine, it could travel with your oil until it becomes lodged between two pieces of metal rubbing together in your engine which will cause a lot of issues if it is not identified and apprehended in a timely manner.

In short, regardless of if your oil cap as a whole is lost within your engine bay or if you have lost pieces of it in the actual engine itself, you should take it to your local shop and have them take a look into it for you. 

Best places to find a replacement cap

There are many sources and ways of getting your oil filler cap. The most convenient and most reliable way of acquiring your oil cap is through an auto parts store. However, if you have the time and want to go with the cheaper alternative, there are plenty of online options to take such as Amazon or eBay.

Sometimes though, you may find yourself far from home with no auto parts store in sight. In this case you do not have the luxury of shopping online or acquiring your oil cap through your local auto parts store. In this case, you may be able to stop by the closest gas station if you discover that you are in need of a new oil cap.

However, you really shouldn’t count a typical gas station carrying the oil cap you need. If you decide that you want to be precise and obtain the correct part with absolute peace of mind, you can always go to your vehicle’s dealership.

Are all oil caps the same?

When looking for your replacement oil filler cap there is the inevitable question of, “Are all oil caps the same?” The short answer to this extremely popular question is no.

Not all oil caps are universal, however some caps may interchange with two seperate vehicles. For instance, do not expect to be able to use an oil cap off of a Silverado and place it on your Mitsubishi Eclipse.

However, if you find that you can obtain an oil cap from a GMC Sierra 1500 for your Chevrolet Silverado 1500, there is a much higher chance of that working depending on what year the vehicle was made in.

If you were to get online or walk into your local auto parts store you will likely see a “universal” oil cap. Just make sure that before you decide to purchase your cap, you need to read the description provided and make sure your vehicle is listed as a correct match for the oil cap. 

Symptoms of a loose oil cap 

There are many signs and symptoms of a loose or bad oil cap. The most noticeable sign of a bad or loose oil cap is the loss of oil within your vehicle. The oil escapes from the oil cap and sprays onto the engine bay which will not only lower your oil pressure, but will also cause a vacuum leak and cause quite a mess on everything within reach.

There is also the chance of oil spraying onto your hot engine components which can cause smoke to form under your hood and surface infront of your windshield causing an unsafe driving situation. 

Tips on how to avoid losing oil caps in the future

After taking off the oil cap, always ensure that it has been put back on tightly. Even if the oil cap has been taken off at an establishment or place of business, double check that it is on correctly.

A trick to confirm the oil cap is never left off, is to put the oil cap on or near the hood latch to where the hood cannot be shut without putting the oil cap back on, this also makes sure the oil cap does not get dropped down into the car and becoming lost.

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